UNCLASSIFIED

AMC PAMPHLET AMCP706-240

ENGINEERING DESIGN HANDBOOK

GRENADES (u)

HEADQUARTERS, U.S. ARMY MATERIEL COMMAND DECEMBER 1967

UNCLASSIFIED UNCLASSIFIED £ ^ Niyrinayzui LI! AMC PAMPHLET AMCP 706-240

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ENGINEERING DESIGN HANDBOOK

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Thia material contains information affecting GROUP 3 the national defense of the United States within the meaning of the Espionage Laws, Title 18, Downgraded at 12 year U.S.C., Sec. 793 and 794, the transmission or intervals; not automati­ revelation of which in any manner to an cally declassified. unauthorized person is prohibited by law.

HEADQUARTERS, U.S. ARMY MATERIEL COMMAND DECEMBER 1967

Ai«infipyTm

UNCLASSIFIED UNCLASSIFIED

HEADQUARTERS UNITED STATES ARMY MATERIEL COMMAND WASHINGTON, D.C. 20315

AMC PAMPHLET 13 December 1967 No. 706-240

ENGINEERING DESIGN HANDBOOK

GRENADES (U)

This pamphlet is published for the information and guidance of all concern ed.

(AMCRD-R)

FOR THE COMMANDER:

OFFICIAL: CLARENCE J. LANG Major General, USA Chief of Staff

DISTRIBUTION: S p e c ia 1

UNCLASSIFIED AM CP 706-240

PREFACE

The Engineering Design Handbook Series of the Army Materiel Command is a coordinated series of handbooks containing basic information and fundamental data useful in the design and develop­ ment of Army materiel and systems. The handbooks are authorita­ tive reference books of practical information and quantitative facts helpful in the design and development of Army materiel so that it will meet the tactical and the technical needs of the Armed Forces. This handbook on Grenades has been prepared as an aid to scientists and engineers engaged in military research and develop­ ment programs, and as a guide and ready reference for military and civilian personnel who have responsibility for the planning and interpretation of experiments and tests relating to the performance of military materiel during design, development and production. The text and illustrations were prepared by Lino-Tech, Incorpo­ rated, for the Engineering Handbook Office of Duke University, prime contractor to the Army Research Office-Durham. Many valu­ able suggestions were made by personnel from Picatinny Arsenal, Edge wood Arsenal, and the U. S. Army Harry Diamond Labora­ tories. Comments and suggestions on this handbook are welcome and should be addressed to Army Research Office-Durham, Box CM, Duke Station, Durham, North Carolina 27706.

UNCLASSIFIED AM CP 706-240 UNCLASSIFIED

TABLE OF CONTENTS

Paragraph Page P R E F A C E ...... i LIST OF ILLUSTRATIONS...... vi LIST OF T A B L E S ...... viii

CHAPTER 1(U) INTRODUCTION I— 1 (U ) Purpose of Handbook...... 1—1 1—2(U) General...... I— 1 1—2.1(U) Grenade Payloads...... 1—1 1—2.1.1 ( U ) Explosive Grenades...... 1—1 1—2.1.2 (U ) Chemical Grenades...... 1—1 1—2.2 (U) Grenade Projection...... 1—2 1—3(U) History...... 1—2 1—4 (U ) 40 mm Grenade Systems...... 1—3 1—4.1 (U ) Materiel and Purpose of System ...... 1—3 1—4.2 (U) Grenade Launcher, M79...... 1—3 1—4.3(U) Grenade Launcher, XM148...... 1—4 1—4.4 (U ) Cartridge, Grenade, 40 mm, HE, M406...... 1—4 1— 4.5 (U) Cartridge, Grenade, 40 mm, Practice, M 407...... 1—5/1—6 (U ) REFERENCES...... 1—5/1—6

CHAPTER 2(C) HAND GRENADES Section I (U ) General 2— 1 (U) Purpose...... 2— 1 2—2 (U ) Typical Hand Grenade Requirements...... 2— 1 2—3 (U ) General Test Specifications...... 2—2

Section II (C ) Fragmentation Hand Grenades 2—4(U) General...... 2—2 2—5(U) Requirements...... 2—2 2—5.1 (U) Fragmentation Pattern...... 2—2 2—5.2 (U ) Lethality...... 2—2 2—5.2.1 ( U ) Incapacitation Tim e...... 2—2 2—5.2.2(U ) Effective A re a ...... 2—3 2—5.2.3(U) Effectiveness Criterion...... 2—3 2—5 .3 (U ) Size, Weight, and Shape...... 2—3 2— 5.4 (U ) Safety...... 2—3 2—5.5 (U ) Fuzing...... 2-^4 2—6(C) Design Considerations...... 2— 4 2—6.1 (C ) Lethality...... 2— 4 2—6.1.1(C) Lethality Criterion...... 2— 4 2—6.1.2(C) Number of Incapacitating Fragm ents...... 2— 4 2—6.1.3(C) Lethal Area ...... 2—5 2—6.2(C ) Fragmentation Considerations...... 2—5 2—6.2.1 (C) Mass Distribution of Fragments...... 2—7 ii UNCLASSIFIED UNCLASSIFIED AMCP 706-240

TABLE OF CONTENTS (Conl'd)

Paragraph Page 2—6.2.2 (C ) Fragmentation Efficiency p ...... 2—7 2—6.2.2.1(C) Scaling Formulas for |i...... 2—7 2—6.2.2.2(C) Mott Scaling Formula ...... 2—7 2—6.2.2.3(C) Gumey-Sarmousakis Scaling Formula...... 2— 7 2—6.2.2.4(C) Effective of Explosives on p ...... 2—8 2—6.2.3 ( C ) Velocity of Fragments...... 2—8 2—6.2.3.1 ( C ) Striking Velocity...... 2— 9 2—6.2.3.2(C) Initial Velocity...... 2—9 2—7 (C ) Design Approach...... 2—9 2—7 .1(C ) General...... 2—9 2—7 .2 (U ) Design Procedure...... 2— 11 2—8(U) Physical Design Factors...... 2— 12 2—8.1 (U ) Size...... 2— 12 2—8.2 (U ) Weight...... 2— 12 2—8.3 (U ) S h ap e...... 2— 12 2—8.4 (U) Controlled Fragmentation...... 2— 15 2—8.4.1 (U) Notched Casing...... 2— 15 2—8.4.2 (U ) Notched Wire or Notched Rings...... 2— 15 2—8.4.3(U ) Fragmentation Losses...... 2— 17 2—8.4.3.1 (U ) Fuze Volume...... 2— 17 2—8.4.3.2(U) Packing Losses...... 2— 17 2—8.4.3.3 (U ) Breaking and Chipping of Fragments...... 2— 17 2—8.4.3.4(U) Closing Cap Losses...... 2— 17 2—8.5(U) Effectiveness of Various Grenade Designs 2—17 2—8.5.1(U) Overall Probability of Incapacitation...... 2— 18 2—8.5.2(U) Spherical Versus Barrel-shaped Grenades.. 2—18 2—9 (U ) Fuzing...... 2— 19 2—9.1 ( U ) Proximity Fuzing...... 2— 19 2—9.2 (U ) Pyrotechnic Time Delay Fuzing...... 2— 19 2—9.2.1 (U ) Safety and Arm ing...... 2—20 2—9.2.2(U ) Striker Assem bly...... 2—21 2—9.3 (U ) Impact Fuzing...... 2—22 2—9.3.1 (U ) Impact Switches...... 2—24 2—9.3.2(U) Thermal Switches...... 2—24 2—9.3.3(U ) Thermal Batteries...... 2—25 2—9.3.4 (U ) Electric Detonators...... 2—26 2— 1 0 (U ) Explosive Trains...... 2—26 2— 10.1 (U ) Explosives...... 2—27 2—10.2(U) Explosive Train Components...... 2—27 2— 10.2.1 (U ) Primers...... 2—27 2—10.2.1.1 (U ) Percussion Primers...... 2—30 2— 10.2.1.2 (U ) Percussion Primer Construction...... 2—30 2— 10.2.1.3 (U ) Priming Compositions...... 2—30 2— 10.2.2 (U ) Detonators...... 2—30 2—10.2.2.1(U) Flash Detonators...... 2—31 2—10.2.2.2 (U) Explosives for Detonators...... 2—32 2—10.2.2.3 (U ) General Design Considerations...... 2—32 2—10.2.3 (U) Delay Elements...... 2—33

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TABLE OF CONTENTS (Conf'd)

Paragraph Page

2— 10.2.3.1 (U ) Delay Compositions...... 2—34 2— 10.2.3.2 (U ) Gas-producing Delay C harges...... 2—34 2—10.2.3.3(U) Gasless Delay Charges...... 2—34 2—10.2.4(U) Relays...... 2 -3 4 2— 10.2.5(U) Main Charges...... 2—35

Section III (U ) Chemical Hand Grenades 2— 11 (U ) General...... 2—35 2— 12 (U ) Irritant Grenades ...... 2—35 2— 12.1 (U ) General Requirements...... 2—35 2— 12.2 (U ) Agents...... 2—35 2— 12.2.1 (U ) Dispersal...... 2—35 2— 12.2.2 (U ) Types of A gen ts...... 2—36 2— 12,3 (U ) Design Considerations...... 2—36 2— 12.3.1 (U ) G en eral...... 2—36 2— 12.3.2 (U ) Burning-type Irritant Grenade...... 2—36 2—12.3.3 (U) Bursting-type Irritant Grenade...... 2—38 2— 12.3.4 (U ) Fuzing...... 2—39 2— 1 3 (U ) Incendiary G renades...... 2— 40 2— 13.1(U) G en eral...... 2— 40 2— 13.2 (U ) Pyrotechnic Composition...... 2— 41 2— 13.3(U) Design Considerations...... 2— 41 2— 14 (U ) Smoke Grenades...... 2—41 2— 14.1 (U ) G en eral...... 2— 41 2— 14.2(U) Smoke Compositions...... 2— 43 2— 14.2.1 (U ) Dispersal...... 2— 43 2— 14.2.2 (U ) Types of Compositions...... 2—43 2— 14.3(U) Design Considerations...... 2— 44 2— 14.3.1 (U ) Burning-type Smoke Grenades...... 2— 44 2—14.3.2 (U ) Bursting-type Smoke (WP) Grenades...... 2— 46 2— 14.3.3(U) Fuzing...... 2— 46 (U) REFERENCES...... 2 -^ 8

CHAPTER 3 (U ) RIFLE GRENADES 3— 1 (U ) General...... 3— 1 3—2 (U ) Types of Rifle Grenades...... 3— 1 3—3 (U ) General Requirements...... 3— 1 3—4 (U) Terminal Effects...... 3— 1 3—5 (U ) Operation and Accuracy...... 3— 4 3—6 (U) High Explosive Antitank Rifle Grenade...... 3—5 3—6 .1 (U ) General...... 3—5 3—6.2 (U ) Shaped Charges...... 3—5 3—6.2.1 (U ) Shaped Charge Principles...... 3—6 3—6.2.2 ( U ) Shaped Charge Design...... 3—7 3— 6.2.2.1 ( U ) Charge Characteristics...... 3—8 3—6.2.2.2(U) Liner Characteristics...... 3—9 3—6.2.2.3 (U ) Standoff...... 3—9 3—6.3 (U ) Stability...... 3—9

IV AM CP 706-240

TABLE OF CONTENTS (Conf'd)

Paragraph Page 3—6.4 (U ) Fuzing...... 3— 10 3—6.4.1 (U ) Mechanical Fuzing Methods...... 3— 10 3—6.4.2 (U ) Electrical Fuzing Methods...... 3— 11 3—6.4.2.1 ( U ) Piezoelectric Fuzing...... 3— 11 3—6.4.2.2 (U) Inertia Generator-type Fuzing...... 3— 12 3—6.4.2.3 (U ) Proximity Fuzes...... 3— 12 3—6.4.3(U) Safety and Arming...... 3— 12 3—7 (U ) Chemical Rifle Grenades...... 3— 13 3—7 .1 (U ) Smoke Compositions...... 3— 14 3—7.2(U) Design Considerations...... 3— 14 3—7.2.1 (U ) Stability...... 3— 14 3—7.2.2 (U ) Fuzing...... 3— 14 3— 7.2.2.1 (U ) Streamer-type Smoke G ren ad e...... 3— 14 3—7.2.2.2(U) Impact-type Smoke Grenade...... 3— 16 3— 8(U) Propellant Charges...... 3— 16 (U) REFERENCES...... 3— 19/3— 20

CHAPTER 4 (U) TRAINING AND PRACTICE GRENADES 4— 1 (U ) General...... 4— 1 4—2 (U ) Training Grenades...... 4— 1 4—3 (U ) Practice Grenades...... 4— 1 4—3.1 (U ) Practice Hand Grenade...... 4— 1 4—3.2 (U ) Practice Rifle Grenade...... 4—2 (U ) R E FE R E N CE S...... 4—3/4— 4 (U ) IN D E X ...... I— 1

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LIST OF ILLUSTRATIONS

Fig. No. Title Page

1—1 (U) Grenade Launcher, 40 mm, M79...... 1—3 1—2(U) XM16E1 Rifle With Grenade Launcher, 40 mm, X M 148...... 1—4 1— 3 (U ) Cartridge, Grenade, 40 mm, HE, M406...... 1—5/1—6 2— 1 (U ) Fragmentation Pattern for a Typical Fragmentation Hand Grenade...... 2—6 2—2 (U ) Graph for Determining C / W ...... 2— 10 2—3(U) Graph for Determining vQ ...... 2— 11 2—4(U) Possible Shapes for Hand Grenades...... 2— 14 2—5 (U ) Effect of Shape on Grenade Effectiveness. 2— 15 2—6(U) Notched Casing for Controlled Fragmentation.. 2—16 2—7 (U ) Grooved Wire and Grooved Rings for Controlled Fragmentation...... 2— 16 2—8 (U ) Notched Wire for the M26 Fragmentation Hand Grenade...... 2— 17 2—9(U) Approximate Fragmentation Pattern for a Barrel-shaped Grenade...... 2— 18 2— 10 (U ) Typical Pyrotechnic Time Delay Fuze...... 2— 19 2— 11 (U ) Safety Lever and Pull Ring Assem bly...... 2—21 2— 12 (U ) One Cause of Premature Function in Hand Grenade...... 2—22 2— 13(U ) M217 Electric Fuze...... 2—23 2— 1 4 (U ) Electrical Circuit of the M217 Fuze...... 2—24 2— 1 5 (U ) Trembler-type Impact Switch...... 2—25 2— 1 6 (U ) Fusible-link Thermal Switch...... 2—25 2— 17 (U ) Spring-loaded Fusible-link Thermal Switch...... 2—26 2— 18 (U ) Elements of a Typical Fragmentation Hand Grenade Explosive Train...... 2—27 2— 1 9 (U ) Typical Percussion Primer...... 2—30 2—20(U ) Typical Flash Detonators...... 2—31 2—21 (U ) Loading Pressure Versus Density Nomograph...... 2—33 2—22 (U ) Typical R elay...... 2—34 2—23(U ) Relay Used as Last Charge Increment in a Delay Column...... 2—35 2—24(U ) Typical Burning-type Irritant Grenade...... 2—38 2—25(U ) Irritant Grenade Loaded With CN and DM Agents...... 2—39 2—26(U ) Irritant Grenade With CS Agent Loaded into Gelatin Capsules...... 2—40 2—27 (U ) Typical Burst-type Irritant Grenade...... 2— 41 2—2 8 (U ) Delay-type Detonator...... 2—41 2—2 9 (U ) M 14 Incendiary Grenade...... 2—42 2—30(U ) M18 Colored Smoke Hand Grenade...... 2—45 2—31 (U ) White Smoke (H C ) Grenade...... 2—46

VI AMCP 706-240

LIST OF ILLUSTRATIONS (Cont'd)

Fig. No. Title Page

2—32(U) WP Smoke Hand Grenade...... 2—47 2— 33 (U ) WP Smoke Hand Grenade With Scored Fragmenting Casing...... 2— 47 3— 1 (U ) Typical Rifle Grenades...... 3—2 3—2 (U ) Hand Grenade Adapted for Rifle Firing...... 3—3 3—3 (U ) Methods of Firing Grenades from Rifles...... 3—4 3—4 (U ) Rifle Grenade Launcher...... 3— 4 3—5 (U ) Rifle Grenade Sight...... 3—5 3—6(U ) Penetrations Produced by Explosive Charges With and Without Cavities...... 3—6 3—7 (U ) Collapse of a Shaped Charge Cavity Liner...... 3—7 3—8 (U ) Hydrodynamic Deformation of Jet and Target...... 3—7 3—9 (U ) Major Components of a H E AT Rifle G ren ade...... 3—8 3—10(U) Typical Charge Shapes...... 3— 8 3— 11 (U ) Basic Principle of Spit-back Fuze...... 3— 10 3— L 2 (U ) Basic Principle of Inertia-type Fuze ...... 3— 11 3— 13 (U ) Basic Piezoelectric-type Fuze...... 3— 12 3— 1 4 (U ) Simple Out-of-line Detonator...... 3— 13 3—15(U) Streamer-type Smoke Grenade...... 3— 15 3—16(U) Burning-type Impact Smoke Grenade...... 3— 17 3—17(U) Bursting-type Impact Smoke Grenade...... 3— 18 3— 1 8 (U ) Cartridges for Rifle Grenades...... 3— 19/3— 20 4— 1 (U ) Training Hand Grenade...... 4— 1 4—2 (U ) Practice Hand G renade...... 4—2 4—3 ( U ) Practice Rifle Grenade...... 4—3/ 4— 4 AMCP 706-240

LIST OF TABLES

Table No. Title Page 2— 1 (C ) Effect of Explosives on p ...... 2—8 2—2(C) Values of Gurney Constant yj2E for Commonly Used Explosives...... 2—9 2—3 (U ) Probability of Grenade Impact Within x Feet of T a rg e t...... 2— 13 2—4(C) Characteristics of Military Explosives...... 2—28 2—5 (U ) Compatibility of High Explosives With Metals and Other Materials...... 2—29 2—6 ( U ) Common Priming Compositions...... 2—31 2—7 (U ) Gasless Delay Compositions in Current U s e . 2—34 2—8(U) CN Irritant Grenade Composition...... 2—37 2—9(U) DM Irritant Grenade Composition...... 2—37 2— 10 (U) CS (Encapsulated) Irritant Grenade Composition...... 2—37 2— 11 (U ) Compositions for Bursting-type Irritant Grenades...... 2—38 2— 12 (U ) Incendiary Grenade Composition (Thermate) .. 2—42 2— 1 3 (U ) Colored Smoke Hand Grenade Compositions.... 2— 43 2— 14 ( U ) White Burning Smoke ( HC ) Composition.... 2— 44 2— 15 ( U ) Burning Temperature of Colored Smoke Hand Grenades...... 2— 44 2—16 (U ) Burning Time of Colored Smoke Hand Grenades...... 2— 45 2— 17 (U ) Internal Pressure of Colored Smoke Hand Grenades...... 2— 45 3— 1 (U ) Streamer-type Smoke Grenade Compositions ...... 3— 14 AMCP 706-240

CHAPTER 1 (U)

INTRODUCTION

1—1 (U) PURPOSE OF HANDBOOK 1—2.1.1 (U) Explosive Grenades

This handbook provides data that the Explosive grenades are either of the grenade designer can use to develop a fragmentation-type, the blast-(offensive) munition that will meet the general require­ type, or the shaped-charge type. Fragmen­ ments prescribed by the Army. Design data tation grenades are used primarily to in­ are presented for both hand grenades and flict personnel casualties, and, therefore, rifle grenades. Rifle grenades are now are designated as antipersonnel (APERS) obsolete, however, the data are presented grenades. Fragmentation grenades can for historical reasons, completeness, and, also be used against materiel, but their perhaps, use at some later time. The de­ effectiveness is limited in this application. sign of self-propelled grenade-type projec­ A blast, or offensive, grenade produces tiles, such as rocket grenades and their no fragments (except the metal parts of associated launching devices, are beyond the fuze) when it detonates. Its antiperson­ the scope of this handbook because these nel effects result exclusively from blast and self-propelled "grenades” are generally are significantly less than those of fragmen­ considered to be in the rocket or missile category. tation grenades. Blast grenades have been used in the past for very close combat in the open and for attacking enemy person­ nel in lightly structured buildings or similar 1—2(U) GENERAL structures. Blast grenades were developed A grenade is a small munition for close- prim arily to protect the thrower from range infantry combat within the range of fragments in these close combat situations. mortar fire. Among ail of the weapons used However, control of fragmentation pattern in infantry combat, grenades have a unique of present-day fragmentation grenades and position because they are the individual appropriate training of the users minimize infantryman’s area-fire weapon of oppor­ the danger to the thrower. Therefore, blast tunity. All other forms of area-fire weap­ grenades are obsolete. onry are normally controlled by unit lead­ Shaped charge explosive grenades are ers or others higher in the chain of com­ used primarily to defeat armored vehicles. mand than the individual infantrym an The antipersonnel effects of this type of Hence, grenades provide an area-fire capa­ grenade are limited by specified military bility at the very lowest level, and they can requirements- However, antipersonnel be brought to bear on an enemy much more effectiveness can be provided if required. quickly than any other area-fire weapon. 1

1—2.1.2(U) Chemical Grenades

1— 2.1 (U) GRENADE PAYLOADS The three basic types of chemical gre­ nades in use are: (1 ) irritant, (2 ) incendi­ The payload of a grenade may be ary, and (3 ) smoke. broadly classified as either explosive or chemical. Each of these classifications may Irritant grenades are used to harass or be broken down further, as described in the incapacitate enemy personnel. They axe paragraphs which follow. also used for riot control.

28S-6SJ O - 63 - l 1-1 AAACP 706-240

Incendiary grenades contain chemicals World War I, however, that well-designed that bum with a very high temperature. grenades, capable of being mass-produced, They are used primarily for destroying were developed. During World War I, both equipment. sides used grenades in large quantities to support their trenchline raids against one Smoke grenades are used for screening another. Also, it was during this war that and for signaling. The payload may be a the rifle grenade evolved into a practical chemical that produces white smoke, which and useful infantry weapon. is normally used for screening, or it may be a chemical that produces colored smoke, Grenades were used extensively during which is normally used for signaling. World War II, particularly in actions such as the hedgerow fighting in Normandy. A 1—2.2(U) GRENADE PROJECTION weapons evaluation of the Korean Conflict indicates that the grenade was one of the The methods of projecting grenades pro­ major weapons, and that almost all "in­ vide the means for classifying the two main fighting” against Communist forces was types of grenades; namely, hand grenades attended by hand-grenade action 3V and rifle grenades. A hand grenade, as its name implies, is thrown by hand, without Grenades have been a particularly use­ the use of any auxiliary equipment. Sim­ ful weapon in guerrilla-type wars, such as ilarly, a rifle grenade is fired from an infan­ the Indo-China War and the Viet-Nam War. try rifle. To fire a rifle grenade, however, Guerrilla warfare is often fought at dis­ an adapter, or auxiliary barrel, must be tances within the minimum range of artil­ attached to the rifle. Furthermore, a special lery and mortars, and fragmentation gre­ blank cartridge must be used to propel the nades become the main source of area-fire. grenade. The use of ball or AP ammunition There is still a marked physical resem­ is likely to detonate the grenade, killing blance between World War I grenades and the grenadier. present-day grenades. However, over the Any hand grenade can be converted to a years, there have been great advances in rifle grenade by the use of a special gre­ grenade safety, reliability, and effective­ nade adapter. Conversely, some rifle gre­ ness, For example, the fragmentation pat­ nades may be used as hand grenades, tern, and the size of fragments, can now particularly those with chemical payloads. be predicted and controlled to a reasonable degree. Electrical fuzing is used in some Hand grenades, while normally pro­ types of rifle and hand grenades. Further­ jected by throwing, must be capable of more, some rifle grenade fuzes employ an being rigged as a booby trap. Strictly out-of-line, or interrupted, explosive train speaking, booby trapping is not a method for safety; these fuzes rotate the explosive of projection; nevertheless, the ability of a train into alignment by sensing, or recog­ hand grenade to be used as a booby-trap nizing, the firing environment device is a major design requirement for many hand grenades. Rifle grenades, although they have been improved greatly over the years, still 1—3 (U) HISTORY possess certain inherent tactical limita­ tions. Their effective range is limited to, Grenades have been part of the weapons at most, 200 yards, and they are relatively mix in infantry forces for centuries They inaccurate. Furthermore, they require the were developed in the 15th Century, and use of special adapters and sights that were used in many wars down through the must be attached to the rifle before the years, including the Civil War and Russo- grenade is fired. Because of these limita­ Japanese War (1904). It was not until tions, rifle grenades are now being replaced by weapons such as the antitank M72 •Superscript numbers refer to References at the end o f each HEAT rocket and the antipersonnel M79 chapter. 40 mm grenade launcher. Both of these

1—2 AMCP 706-240 weapons, while not actually rifle grenades, of 30 meters to 350 meters. This is the perform the same functions, and are more area between the maximum throwing range effective and reliable. Since the 40 mm is for the hand grenade and the minimum essentially a grenade-type weapon system, range for mortar fire. They are suitable a brief description is given below. for direct firing against vertical targets such as openings in buildings, cave en­ 1—4(U) 40 mm GRENADE SYSTEMS3 trances and bunker apertures at ranges 1—4.1 (U) MATERIEL AND PURPOSE OF SYSTEM. of 30 meters to 150 meters. For area fire they can be used at ranges of from 30 The 40 mm Grenade Systems include meters to 400 meters maximum range. the following items: Each of the system components is described (a ) 40 mm Grenade Launcher, M79 in the paragraphs which follow.

(b ) 40 mm Grenade Launcher, XM148 1—4.2(U) GRENADE LAUNCHER. M79.

(c ) Cartridge, Grenade, 40 mm, HE, The M79 Launcher as shown in Fig. 1—1 M406 is simple in design and construction. Basi­ cally, it is a single-shot, shoulder-fired, (d ) Cartridge, Grenade, 40 mm, Prac­ shotgun type of weapon, with break-open tice, M407 action Its nominal caliber is 40 mm. The The systems axe provided for defensive weight of the projector, without cartridge, and offensive use by small units or individ­ is 6 lb; loaded, its weight is 6.5 lb. The ual combatants. They provide effective overall length is 28.625 in The length of area target fire coverage in the range zone the barrel is 14.71 in. The forward 12 in.

FIGURE I — 1 (U) — GRENADE LAUNCHER. dO MM. M79

1-0 AMCP 706-240 of the barrel are rifled, with 6 rifling oz, and the overall length is 3.9 in. Its com­ grooves 0.01 in. deep, of uniform twist, ponents are an aluminum cartridge case right hand; one turn in 48 inches. M l 18, with percussion primer M42 and propellant charge, and projectile (M406) 1—4.3(U) GRENADE LAUNCHER, XM146 with explosive filler and point-detonating fuze M551. The projectile also includes a The XM148 Launcher shown in Fig. 1—2 windshield of ogival shape covering the has the same capability as the M79 fuze. The weight of the projectile assembly Launcher, but is designed for use on the as it leaves the muzzle is 6 oz (0.375 lb) M16 Rifle. It is attached to the rifle by and the length is 3.1 in. means of a special handguard. The stand­ ard rifle handguard is removed from the The propelling charge of approximately rifle and replaced with the spiral hand- 365 mg of M9 propellant is contained in a guard to which the launcher has been fixed. brass cup, which in turn is held in a retain­ It is expected that the launcher, when er which surrounds the cup and is provided once attached, will remain as a fixed part with holes in the forward portion. The of the rifle. cartridge employs the high-low propulsion system in which the gas output of the pro­ The length of the barrel in this configura­ pellant is confined, temporarily, at high tion is 10 in., 4.71 in. shorter than the bar­ pressure in the brass propellant cup and rel length of the M79 Launcher. The rifling retainer. The pressure, approxim ately has the same characteristics as that of the 35000 psi, ruptures the brass cup through M79 Launcher, but the rifled length is cor­ the holes in the retainer, and the propellant respondingly shorter. The shorter length gas then expands into the free space of the barrel results in a reduction of the stand­ cartridge case, creating a chamber pres­ ard muzzle velocity from 250 ft per sec sure of about 3000 psi. The pressure acting to 245 ft per sec, and spin from 3750 rpm on the grenade to accelerate it through the to 3675 rpm, but the maximum range is launcher bore is the lower pressure. Since maintained at 400 meters. The weight of the force exerted by the projector against the rifle and launcher assembly-,-loaded the man firing it is proportional to the force with a magazine of ball ammunition and acting on the grenade, the advantage of one grenade--is approximately 11 lb. the high-low system is evident.

1—4.4(U) CARTRIDGE, GRENADE, 40 mm, HE, M406 The projectile for the M406 Cartridge is a 40 mm caliber antipersonnel, high explo­ The M406 Cartridge shown in Fig. 1—3 sive, fragmentation grenade. Its overall is a complete round assembly weighing 8 length, including the ogival windshield, is

FIG U R E 1 — 2(U) — XAUSHI R IF L E WITH GRENADE LAUNCHER, 40 MM, XM146 AMCP 706-240

FIGURE ) — 3(U) — CARTRIDGE, GRENADE, 40 MM, HE, M406

3.1 in., and the weight is 6 02. The bursting of the grenade. Arming is assured after 27 charge is 1.25 oz of Composition B. The meters of flight. grenade body is formed of notched, rectan­ gular 9teel wire. Upon detonation, the 1—4.5 (U) CARTRIDGE, GRENADE,40mm, PRACTICE, notched wire of the grenade body breaks M407 into highly lethal fragments. The grenade The M407 Cartridge is a complete round has an effective casualty radius (the radius assembly designed to be safe to fire for of a circle about the point of detonation in practice purposes which yields spotting which normally we may expect 50% of the signature of the point of impact of the gre­ exposed personnel to become casualties) nade. Essentially the same components are of 5 meters. used as for the M406 Cartridge, except The M551 Point-Detonating Fuze is that the grenade is inert loaded to weight armed by the combined action of setback and is provided with a spotting charge of and centrifugal forces. With this fuzing, the about 2 g of yellow smoke powder. The grenade will remain unarmed for about 0-25 smoke cloud can be detected from the firing sec after firing. Thus accidental impacts position at maximum range. The ballistic or short flights--under 18 meters from the performance and fuze action exactly dupli­ launcher--should not result in functioning cate those for the M406 Cartridge.

(U) REFERENCES

2. S. L. Marshall, Infantry Operation and Weapon Usage in Korea, Report ORU- 1. G. G. Barnes, Analysis of Fragmenta­ 0-13, Operations Research Office, tion Grenades and Grenade Launchers Johns Hopkins University, Silver in Counterinsurgency Operations, Spring, Md., 27 October 1951. NOTS TP 3526, U. S. Naval Ordnance Test Station, China Lake, Cal., Sep­ 3. TM 9-1330-200, Grenades, Hand and tember 1964 (SECRET). Rifle.

1—5 / 1 —6 AMCP 706-240

CHAPTER 2 (C) HAND GRENADES

SECTION I (U) GENERAL

2—1 (U) PURPOSE hit with an injurious fragment shall be less than 1 in 100,000” and description of the A hand grenade is a small, relatively position of the thrower; for example, "prone lightweight weapon used for close combat, man in winter clothing with average terrain generally within a maximum range of about cover”. Also, to the extent possible, physi­ 40 meters. The most common use of hand cal characteristics should be general with grenades is to inflict personnel casualties only the maximum specified; that is, maxi­ on the enemy. For this purpose, high ex­ mum weight, maximum size, etc. However, plosive fragmentation-type hand grenades all hand grenades must meet the following are used almost exclusively. general requirements: Hand grenades are also used for harass­ a. Be operable over a temperature ing the enemy, for signaling and screen­ range o f -40° to +■ 125° F a t any humidity ing, and for incendiary use. For these pur­ level. poses, chemical hand grenades are used. b. Be operable after prolonged storage 2—2(U) TYPICAL HAND GRENADE REQUIRE­ in a packaged state at temperatures be­ MENTS tween -65° and + 160°F at any humidity level. However, the low-temperature stor­ Each type of hand grenade is designed age limit for some types of chemical-type to meet certain specific requirements with grenades may be -40° F. respect to lethality, size, weight, etc. It is desirable that military requirements and c. Be operable after being subjected in characteristics be so specified as to give a packaged state to the atmospheric pres­ the designer-developer maximum flexibility sure variations, shock, and vibration en­ in achieving a most nearly optimum design. countered during air transport­ Historically, military requirements, in the ed Be operable after being subjected to effectiveness area, have been specified in the shock and vibration encountered during terms of effects against a specific test truck and rail transport, whether trans­ arena which is not necessarily representa­ ported in an unpacked or packed state. tive of combat usage of the item and may not be conducive to the optimum design. e. Be waterproof. Military effectiveness requirements should /. Be operable after being dropped by be specified in terms of specific targets, parachute. Should the parachute fail to with description of such targets; the fre­ open, they must remain safe for disposal. quency of engagement of each specified target; and the distribution of ranges at g. Be simple to operate under all com­ which each specified target is engaged. bat conditions by personnel having mini­ Relative to safety of the thrower, the mili­ mum instructiorL tary requirement should specify the level h. Be safe. of risk which is acceptable; for example, "the probability that the thrower will be i. Meet requirements of MIL-STD-331.

2-1 AM CP 706-240

2—3(U) GENERAL TEST SPECIFICATIONS to tem perature and humidity extremes, while Test No. 115, "Static Detonator There are many standard military speci­ Safety”, provides methods of testing for fications that prescribe test procedures for detonator safety. determining if a hand grenade meets the The design specification for a grenade general requirements of par. 2—2. For ex­ will usually specify the test specifications ample, specifications for immersion testing that must be used in the design of a par­ may be used to determine if the grenade is ticular grenade. In some cases, only the waterproof. Or, specifications for transpor­ requirements will be specified, and the de­ tation vibration testing may be used to signer will have to determine which speci­ determine if the grenade can withstand the fications must be used to determine if the rigors of truck transport. requirements are met. In either case, the There are also standard military specifi­ designer must keep the requirements in cations for testing grenade components. mind from the very beginning of a project For example, MIL-STD-331, Test No. 105, to the end, and should continually consult "Temperature and Humidity”, provides the test specifications to insure that his methods of testing a fuze for its resistance design can meet the test requirements.

SECTION II (C) FRAGMENTATION HAND GRENADES

2—4(11} GENERAL spatial distribution of fragments. However, because of certain practical factors, which This section describes the military re­ are discussed later, a uniform spatial dis­ quirements specified for a fragmentation tribution is impossible to attain. Therefore, hand grenade. Following this, the design for all present-day fragmentation grenades, considerations involved in meeting these a nearly uniform spatial distribution is re­ requirements are discussed, and a typical quired, and can be attained. A nearly uni­ design approach is illustrated. form spatial distribution provides reasona­ ble assurance that a target within the frag­ 2 -5 (U) REQUIREMENTS mentation range of the grenade will be hit In addition to the requirements speci­ by fragments. fied in par. 2—2 for all hand grenades, a fragmentation hand grenade must meet 2—5.2(U) LETHALITY certain operational requirements. These re­ quirements, which are normally given in The lethality of a grenade is a measure the design specifications for the grenade, of the grenade’s ability to incapacitate an are discussed briefly in the paragraphs enemy. In this sense, incapacitation means which follow. either to kill him or to severely wound him so that he cannot fire a weapon or offer 2—5.1 (U) FRAGMENTATION PATTERN effective resistance. The required spatial distribution of frag­ 2—5.2.1 |U) Incapacitation Tims ments will be given in the design specifica­ tion. Since it is impossible to predict a hand A requirement for fragmentation gre­ grenade’s orientation with respect to the nades is that they incapacitate an enemy target at the time of detonation, ideally, within a certain time. Since hand grenades the grenade should produce a uniform are used for close combat, this time must

2 - 2 AMCP 706-240 be very short; for present-day grenades, it the desired distance or thrown very accu­ is usually immediate or at most 5 sec, rately. The same is true if the grenade is too light, in which case, distance and accu­ 2—5.2.2 (U) Effective Ar*a racy are affected by wind forces. The design specification will contain a The size, weight, and shape require­ requirement that the hand grenade frag­ ments for a hand grenade are usually given ments must be lethal to specified damage in the design specification, and are speci­ level out to a certain distance and safe to fied in a manner that provides some leeway the thrower beyond a second specified dis­ for the grenade designer. For example, a tance. The effective area is normally ex­ maximum weight for the grenade is nor­ pressed as a circular area about the point mally specified rather than a precise of buret within which a specified average weight. A typical design specification may probability of incapacitation of a specific state that the grenade should be as light target is attained. The safe distance is as practical, but shall not exceed 16 oz. generally associated with the throwing Similarly, maximum dimensions are usually range of the grenade by a typical soldier. specified. For example, if the grenade is to Sound training techniques assist in assur­ be spherical, its maximum diameter will ing that the thrower will not be incapaci­ be specified, which, typically, is about 3 in. tated by his own Item. If the grenade is to be barrel-shaped, the length of its longest axis will be specified, 2—5.2.3 (U) EH*ctivan«si Criterion which, typically, is about 4-1/2 to 5 in. The effectiveness criterion of a fragmen­ tation hand grenade is a measure of the 2—5.4 |U) SAFETY grenade’s capability for incapacitating an enemy within the effective area of the gre­ Safety requirements for the grenade will nade and within the specified incapacitation be given in the design specification. Typical time. The effectiveness requirement is nor­ requirements are: mally expressed as the probability that the (1 ) The thrower must perform some target will be incapacitated within a speci­ type of positive action to cause the grenade fied time period. to arm after it is released. For example, Since the study of wound ballistics is a for a fragmentation grenade to become specialized field in itself, the grenade de­ armed, two separate actions must occur, signer will normally require pertinent data namely: the thrower must first pull a safety relating to fragment lethality. The U.S. pin out of the grenade and then release a Army Ballistic Research Laboratories safety lever when he throws the grenade. possess the latest information in this re­ (2 ) A time delay must be incorporated gard. into the fuze so that the fuze will not ini­ tiate detonation until about 4 or 5 sec after 2—5.3 (U) SIZE, WEIGHT, AND SHAPE the grenade is thrown. The shape of a hand grenade whether (3 ) To protect the thrower, the number it is spherical, cylindrical, or barrel-shaped of incapacitating fragments must be mini­ has little effect on the distance a grenade mum beyond a specified distance from the can be thrown or on how accurately it can point of detonation. For a typical fragmen­ be thrown. However, the size and weight tation hand grenade, this distance is about of the grenade greatly affect these two 60 ft. parameters. If the grenade is too large, or too small, it cannot be gripped properly by (4 ) If the hand grenade is designed for the thrower, and therefore, both distance impact function, it must not detonate im­ and accuracy will be degraded. If a grenade mediately if dropped by the grenadier in Is too heavy, obviously it cannot be thrown the act of throwing. Immediate detonation

2—3 AM CP 706-240 CONFIDENTIAL can be avoided by incorporating a delay- Precise wound ballistic data and cover after-arming feature into the fuze. Typi­ function data are needed to design a gre­ cally, this delay time is 1 sec, since a nade with fragments having a particular grenade dropped from raised-arm height probability of incapacitation as a function will impact the ground in less than this of time and mission. These data are avail­ time. able at the U.S. Army Ballistic Research Laboratories (BRL), Aberdeen Proving 2-5.5 (U) FUZING Ground, Md., and are being updated con­ tinually. Reports BRL R 1269 and The design specification for a fragmen­ BRL MR 1203 provide the most recent tation grenade will specify the manner in wound ballistic data and cover function which detonation should be initiated, i.e., data, respectively. However, because the after expiration of a fixed time after final data Eire being updated continually, the arming or upon impact with the ground. grenade designer should contact BRL for Practically all present-day grenades use the most recent data at the start of a time fuzes, i.e., nonimpact, and these fuzes project. are required to detonate the grenade ap­ proximately 4.5 sec after the grenade is Probabilities of incapacitation of single thrown. fragments conditioned on a hit ( P ^ ) are given in BRL MR 1209 as a function of If the specification specifies an impact- mass and striking velocity. The form of type fuze, it most likely will also call for the relation is: an overriding time-function feature. This ensures that the grenade will detonate after 3/2 a certain specified time should it fail to -a( m v -b)' hk = 1-e ( 2- 1) detonate on impact.

2—6(C) DESIGN CONSIDERATIONS where m = mass of fragment, grains To meet the requirements specified for vs = striking velocity of fragment, a proposed fragmentation grenade, various fps design parameters must be determined and a,b,n = experimentally derived con­ controlled. During the initial design stages, stants these parameters may be determined analytically using the design formulas The constants — a. b and n — for var­ given in the paragraphs which follow. These ious stress levels and wounding times are formulas are generally accurate enough for given in BRL MR 1269. preliminary design; however, the optimum design parameters can only be determined empirically, based on the results of frag­ 2—6.1.2(C) Number of Incapacitating Fragments mentation tests of developmental gre­ nades2. For a small target located at a certain distance from the point of burst, the ex­ pected number of incapacitating fragments 2—6.1(C) LETHALITY Nk(r) of a given mass is given by the 2—6.1.1(C) Lethality Criterion expression:

The lethality criterion for a fragmenta­ ( 2- 2 ) tion grenade is based on the probability Nm ^hk Nw(0 that a random hit on a man will completely f i r 2 incapacitate that man within a specified time period. This time period is usually immediate or at most 5 sec. where

2—4 CONFIDENTIAL CONFIDENTIAL AMCP 706-240

At = target area exposed to burst, produces a higher lethal area than the sq ft horizontal burst (long axis horizontal), but Nm = total number of fragments of the grenade will most likely settle in a a given mass horizontal position on level terrain. It can P hk = conditioned probability that a be seen that, in the horizontal burst posi­ random hit on the target tion, there are a number of blind spots in will incapacitate the tar­ the fragmentation pattern. While a prelim­ get inary design may be based on achieving a Q = solid angle throughout which uniform fragmentation pattern, fragmenta­ the fragments are pro­ tion tests must be performed to determine jected. (For a spherical the actual fragmentation pattern. Once the grenade, Q would have actual number, mass, spatial distribution, a value of 4 n .) and initial velocity of individual fragments r = distance from point of burst are determined by experimental firings, the to target, ft actual lethal area of the grenade can be calculated. The probability Pk(r) that the target at range r from ground zero will be incapaci­ tated is: Lethal area is often used as a criterion for evaluating the overall effectiveness of a fragmentation grenade. Lethal area is gen­ P J O = 1-e ( 2 - 3 ) erally computed using a high speed digital computer. BRL T N 1510 describes lethal area in detail. Lethal area AL is defined In Eqs. 2—2 and 2—3 it is assumed that as: all fragments travel in a straight line, which is usually an acceptable assumption over the range that the fragments are effective.

A dx dy 2—6.1.3 (C) Lethal Area L (2—4) Because hand grenades are unstabilized in flight and are usually time fuzed, their orientation with respect to the target at time of burst cannot be predicted. Ideally, where P k(x, y) is the probability of incapac­ then, the fragments should be uniformly itation of a target located at x and y rela­ distributed in every direction about the tive to munition ground zero. Lethal area grenade. A spherical grenade would pro­ is not a physical area but rather a weighted vide the most uniform distribution pattern; area where each differential area is but, for purposes of gripping and throwing, weighted by the probability of incapacita­ fragmentation hand grenades are usually tion. Lethal area is proportional to the ex­ barrel-shaped (par. 2—5.3). pected number of casualties produced by a munition. The ideal fragmentation pattern — i. e., fragments distributed uniformly in every direction about the grenade — is impracti­ cal to achieve in a barrel-shaped grenade. In fact, it is impossible to achieve this in a 2—6.2lC) FRAGMENTATION CONSIDERATIONS4 grenade of any shape, even spherical, be­ cause space taken by the fuze and the load From Eq. 2— 1, it can be seen that the opening will interfere with fragment distri­ lethality of a fragmentation grenade P hk bution. A typical fragmentation pattern for depends upon the mass and presented area a barrel-shaped grenade is shown in Fig. of any fragment, and the velocity at which 2— 1. The vertical burst (long axis vertical) the fragment strikes the target. The values

CONFIDENTIAL 2 -5 AMCP 706-240 CONFIDENTIAL

AXIS VERTICAL RESTING ON GROUND

FIG U R E 2 — ) (U) — FRAGMENTATION PATTERN FOR A TYPICAL FRAGMENTATION HAND GRENADE of these parameters are, in turn, deter­ natural fragmentation characteristics. To­ mined by the mass distribution of frag­ day’s grenades are based on techniques ments, the dimensions of the grenade that permit controlled fragmentation (par. casing and the material from which it is 2— 8.4). However, although a fragmenta­ made, the type and weight of the grenade tion casing can be constructed to give a explosive, and the initial velocity of the probable fragment mass, quantity, and fragments at the time of burst. distribution, the controlled fragment characteristics of the casing should be By the use of the mathematical rela­ reasonably close to its natural fragmenta­ tionships between these criteria, the prop­ tion characteristics in regard to average er fragmentation casing can be designed to fragm ent mass so that there will be a give the required number of lethal frag­ higher degree of reliable performance. As ments. Early grenades were made with a method, the grenade can be designed by solid fragmentation casings that relied on considering its natural fragmentation

2 - 6 CONFIDENTIAL CONFIDENTIAL AMCP 706-240 probabilities, and then applying controlled 2—6.2.2.1 (C) Sealing Formulas lor p fragmentation methods to assure reliable performance. The paragraphs which follow Either of two formulas may be used to account for the dependency of p upon the give the design criteria as related to natural fragmentation. Their relationship physical dimensions of the grenade casing to controlled fragmentation is covered in and upon the explosive used. The formulas, par. 2—8.4. given in the paragraphs which follow, are in good agreement for small values of the explosive charge-to-casing mass ratio. 2—6.2.1 1C) Mass Distribution of Fragments 2—6.2.2.2(C) Mott Sealing Formula ® Fragmentation grenades are considered as having thin-walled casings. If it is as­ The following formula relates the value sumed that fragmentation from a thin- of p to the inside diameter and thickness walled casing is the result of two-dimen­ of the casing: sional breakup7, the total number of frag­ ments Nm having a mass greater than m , i / ^ B 5/6d. 1/3 2 8 can be expressed as ( - )

where Nm (2 - 5 ) B = a scaling constant depending upon the explosive and the phy­ where sical characteristics of the M = total mass of grenade casing casing material d; = inside diameter of casing, in. P = fragmentation efficiency of the grenade (par. 2—6.2.2) t = thickness of casing, in.

M The term — represents the total number 2p 2—6.2.2.3 (C) Gurnoy-Sarmousakis Sealing Formula 9 of fragments NT (par. 2—6.2.2); therefore, Eq. 2—5 may be written as The following formula relates the value of p to the inside diameter of the casing, I /2 to the thickness of the casing, and to the ( — ) explosive charge-to-casing mass ratio: Nm = NTe o 2 6 rt(d; + 1) 3/2 - f*1/2 = D y/l * 1/2 (C/W) 2—6.2.2(C) Fragmentation Efficiency p - For a given fragmentation grenade, the (2 - 9 ) quantity p is dependent upon the charac­ teristics of the explosive, the characteris- where D a scaling factor depending tics of the grenade casing, and the physi­ upon the explosive and the cal dimensions of the casing. The term p physical characteristics of can be used as an efficiency factor because the casing material 2 p is actually the arithmetic average frag­ thickness of casing, in. ment mass. Since 2 p represents the arith­ metic average fragment mass, it can be d; inside diameter of casing, in. used to determine the total number of frag- ^ weight of explosive charge, ments NT as follows: grains

N W = weight of fragmenting T 2g ( 2 - 7 ) metal, grains CONFIDENTIAL AMCP 706-240 CONFIDENTIAL

2—6.2.2.4(C) Effect of Explosives on p '° 2—6.2.3(C) Velocity of Fragments

From Eqs. 2—8 and 2—9, it can be seen The probability of incapacitation P hk is that the value of p l/f2 is dependent upon dependent upon the velocity at which the the explosive used in the grenade. The re­ fragment strikes the target (Eq. 2— 1). The sults of a series of test firings to determine striking velocity vs is, in turn, dependent the fragmentation efficiency of various upon the distance from the point of burst, explosives are given in Table 2— 1. While air density, and various fragment param­ the test specimens were not fragmenta­ eters. tion grenades, the test results clearly indi­ cate the variation in the value of p for various types of explosives.

TABLE 2— 1 (C). EFFECT OF EXPLOSIVES ON p 10

Gurney- Cylinder Inside Mott Sarmousakis Thickness, Diameter, scaling scaling t constant constant p l/ 2 Explosive (in .) (in .) c / w (B) (D)

Cast explosives

Baratol 0.254 2.000 0.562 1.237 2.73 2.55 Comp B 0.253 1.999 0.377 0.532 1.18 2.14 C yclotol 0.253 1.999 0.380 0.471 1.05 1.01 (75/25) H-6 0.254 1.999 0.395 0.666 1.47 1.34 HBX-I 0.255 1.999 0.384 0.615 1.36 1.30 HBX-3 0.255 1.999 0.403 0.781 1.72 1.65 Pentolite 0.254 1.999 0.366 0.596 1.32 1.27 (50/50) PTX-1 0.254 1.999 0.367 0.534 1.18 1.14 PTX -2 0.254 1.999 0.373 0.546 1.21 1.17 TNT 0.254 2.000 0.355 0.751 1.66 1.61

Pressed explosives ^

BTNEN/Wax 0.251 2.009 0.379 0.427 0.95 0.92 (90/10) BTNEU/Wax 0.251 2.012 0.367 0.507 1-13 1.10 (90/10) Comp A - 3 0.252 2.012 0.367 0.474 1.17 1.13 MOX-2B 0.248 2.008 0.461 1.289 2.91 2.79 Pentolite 0.252 2.011 0.363 0.638 1.41 1.27 (50/50) RDX-Wax 0.253 2.010 0.370 0.509 1.13 1.09 (95/5) RDX/Wax 0.251 2.014 0.350 0.566 1.26 1.23 (85/15) Tetryl 0.254 2.011 0.371 0.660 1.45 1.41 TNT 0.253 2.012 0.348 0.972 2.15 2.10

* Test specimens — cylinders of AISI 1045 cold-draw-n, seam less-stee 1 tubing; stress relief annealed; hardness approx. 100 Rockwell B t Pressed E xplosives — 2-in. diameter p ellets; 1-in. high; pressed at pressure of 16,000 psi

2-8 CONFIDENTIAL CONFIDENTIAL AMCP 706-240

2—6.2.3. I (Cj Striking Velocity TABLE 2-2(C). VALUES OF GURNEY CONSTANT JW FOR COMMONLY The striking velocity of a fragment vs USED EXPLOSIVES can be expressed by

Expfosi v e ^/2E (fi/ s e c )

* FP r HMX 9500 * ( 2- 10) RDX 9200 Octol 9200 where Composition B 8800 TNT 8000 VQ = initial velocity of fragment, fps (see Eq. 2— 11) • ESTIMATED cD = average drag coefficient of the ratio of explosive density to casing fragment (see Refs. 11, 12) density PJ Pm , and V ^ E are known. The a f = average presented area of procedure for determining vo is as follows: fragment, sq in. (1) Knowing the value of t/d0, deter­ P = density of air, slug/ftJ mine the value of — from Fig. 2—2. P P m = mass of fragment, grains c m (2 ) Multiply Pc/ Pm by this value to r = range from point of burst to obtain C/W. target, ft (3) Knowing the value of C/W, deter­ 2—6.23.21C) Initial Velocity'* mine vQ / y 2E from Fig. 2—3.

For cylinders, the initial velocity vo of a (4 ) Multiply V2E by this value to ob­ fragment can be predicted by: tain v O .

2—7(C) DESIGN APPROACH (»-») 2—7.11Cl GENERAL where A hand grenade designer will be faced with one of two different design problems: y2E = a constant (Gurney constant) (1) he may be required to design a com­ for each type of explosive, ft/ pletely new grenade to conform with a list sec of requirements prepared by the Army; or (2 ) he may be required to redesign an C = weight of explosive, grains existing grenade to improve its perform­ W = weight of fragmenting metal, ance. Obviously, the solution to the sec­ grains ond problem is simpler than that to the first. Much actual test data on lethality, Eq. 2— 11 may be used to calculate vq for fragmentation patterns, fragmentation spheres by changing 0.5(C/W) in the velocity, etc., will be available for the exists denominator to 0.6(C/W ). ing grenade. Therefore, the effects of de­ sign changes on these param eters are Table 2—2 lists values of V ieT for com­ usually relatively easy to predict. On the monly used explosives. For further data on other hand, when designing a new grenade, these explosives, see par. 2— 10. the designer does not have these data Figs. 2—2 and 2—3 may be used to available and, therefore, he must compute determine the value of v O when , the outside such grenade parameters as lethality, frag­ diameter do and thickness t of the casing, mentation pattern , and fragmentation

CONFIDENTIAL 2 -9 AMCP 706-240 CONFIDENTIAL

velocity analytically using the design be used to continue the calculations. In formulas given in the preceding para­ any event, before the calculations are graphs. started, a preliminary physical design of the grenade should be sketched within the Because of the interrelationships among specified size and weight limits, and cer­ the various design parameters, there is no tain values must be chosen as a start. strict procedure for designing a new gre­ These values, of course, should be related nade. Calculations can be started for any to some typical documented data derived one parameter, and the data derived can from experience. Then, the mathematical 2—10 CONFIDENTIAL

2-11 AMCP 706-240 * q Initial action in designprocedure should exceedingly complex and beyond the scope attempted; this will minimize the number nade is covered in the paragraphs which nade before a preliminary design is 2—7.2(D) DESIGN PROCEDURE ing design parameters consistent with mili­ tary requirements. Theanalyst, using weapon high niques speed system and computer tech­ considering will various make parametric concepts, unit studies effectiveness, to evaluate throweroffs, cost safety, effectiveness, trade­ etc., to determine fragmentweight, number fragments, of gre­ nade weight, grenade configuration, etc. handbook.this of of modifications modifications that will of be required during the calculations. This information is later given in this chapter. to the A design of typicala new approach fragmentation gre­ follow. be a system tem analysis analyst by with a the weapon view towardsys­ establish­ optimumparameters as such fragmentsize, The specific procedure for this analysis is c/w

—GRAPH FOR DETERMINING V CONFIDENTIAL CONFIDENTIAL FIG U RE— 3(U)2 68-4 - 0

285-611 It It can be seen from the above that a Experimental models should then be grenade. The equations can then be used made to test the actual performance the of to analyze the performance test to data, improve and the grenade until a sign reliableattained.is de­ considerable amount is of required empirical in design grenadecause of the development interrelated characteristics the of grenade be­ elements. Because of this, a mathematically to see that various param­ sults in certain modifications so that beingthe mathematical madecalculations must calculations can be made to complete the knowledge is needed of the characteristicsof all of the elements that comprise a gre­ design. However, since the calculations are based on some empirically the chosen values, final design musteters are compatible, be and that characteristics the proved desired are attained. out This re­ often be repeated. Sometimes, this must be done a number of paper times appears before feasible. the design-on- 3Z// AMCP 706-240

2—8(U) PHYSICAL DESIGN FACTORS 2—8.3(11) SHAPE'5

The shape of a grenade has little effect 2-8.1 (U) SIZE on the distance that the grenade can be The physical size of a hand grenade thrown. However, grenade shape is one of affects both the distance that the grenade the primary factors controlling the pro­ can be thrown and the accuracy with which jected pattern of the fragments. it can be thrown. To an extent, the size of The three basic shapes usually con­ a grenade is affected by the required frag­ sidered for hand grenades are shown in mentation characteristics. For a given-size Fig. 2— 4. FYom the theoretical patterns preformed fragment (par. 2—8.4), a larger shown, it can be seen that the spherical grenade can produce more fragments than grenade produces the most uniform cover­ a smaller one. Similarly, the C/W ratio of age. The barrel-shaped grenade produces a grenade (par. 2—6.2.3.2) could be in­ nearly uniform coverage, but has some creased by making the grenade larger so voids. The cylindrically shaped grenade that it could hold a greater quantity of produces a relatively nonuniform coverage; explosive. However, the size of a hand gre­ therefore, this shape is generally not con­ nade must be such that it can be comfort­ sidered for fragmentation grenades. It ably gripped and easily thrown. Based on would be considered only if lowest possible past experience, special grenades having unit cost was the overriding design require­ a diameter in the range of 3 to 3-1/2 in., ment. The body of a cylindrically shaped and barrel-shaped grenades having a diam­ grenade can be made essentially as a tin eter of about 2-1/2 to 3 in. and a length can, with notched sheet steel wrapped of about 4 to 5 in., meet these require­ around its inside to produce fragments. The ments. Because of the relatively small Soviet Model RG-42 fragmentation hand lethal area required for a fragmentation grenade is designed this way, making it grenade as compared to other types of much cheaper to produce than the U. S. fragmenting projectiles, the required frag­ M26 fragmentation hand grenade3. How­ mentation pattern can be obtained within ever, tests indicate that the lethal area of the size limitations given above. the U. S. M26 grenade is 1-1/2 to 3-1/2 times that of the Soviet RG-42 grenade.

2—8.2(11) WEIGHT To a certain extent, it is possible to choose the angle over which fragments are The weight of a hand grenade deter­ projected independently of other initial mines, to a great extent, the distance that fragment parameters. Thus, the total un­ the grenade can be thrown and the accu­ fuzed weight W of the grenade, the explo­ racy with which it can be thrown (par. sive charge-to-weight ratio C/W, the weight 2—5.3). Table 2—3 shows the accuracy of each fragment, and the initial fragment with which various weight grenades can velocity may be specified, and any direc­ be thrown from standing, prone, and kneel­ tion of projection of the fragments in space ing positions. The data are based on tests can be realized. For example, for the bar­ conducted with 22 trained soldiers who rel-shaped grenade shown in Fig. 2— 4, the used whatever throwing style they felt was angle 0, which determines the range of most convenient and most accurate. directions from & to ( tt — 8) over which Throws were made with and without gloves, fragments are projected, may be arbitrarily and test results indicate that the gloves chosen. Then, the casing radius R, diam­ had essentially no effect on the throwing eter D, and length L can be set to obtain accuracy. Table 2—3 indicates that accu­ the desired value of C. Since w increases racy decreases as the weight of a grenade continuously with wall thickness T, the increases, although the decrease in accu­ value of T can be set to give the desired racy doe 8 not appear significant for gre­ value of W and, consequently, the desired nades thrown from 20 yd. values of C/W and initial fragment velocity.

2 -1 2 AMCP 706-240

TABLE 2—3(U). PROBABILITY OF GRENADE IMPACT WITHIN X FEET OF TARGET 15

Weight of Grenade

t , ft 12 oz 1 15 oz 2 18 oz 1 22 oz 1

Thrown from 20 yd, prone

0 0 0 0 0 2.5 .10 .10 .09 .02 5.0 .32 .28 .23 .17 7.5 .55 .48 .40 .55 10.0 .77 .68 .60 .72 12.5 .88 .82 .76 .81 15.0 .94 .90 .87 .89 17.5 ■ 97 .95 .93 .94 20.0 ■ 99 .97 .95 ■ 97

Thrown from 30 yd, kneeling

0 0 0 0 0

2.5 .13 .11 .09 .07 5.0 ■ 34 ■ 30 .26 .18

7.5 GO .52 .45 ■ 36

10.0 .76 .68 .61 .51 12.5 .86 .80 .73 -63 15.0 .93 .86 .80 .75 17.5 ■ 95 .90 .86 .85

20.0 ■ 96 .93 .90 .90

Thrown from 40 yd, Standing

0 0 0 0 0 2.5 .06 .06 .06 .04 5.0 .18 .16 .13 .12 7.5 ■ 32 .28 .23 .22 10.0 .47 .41 .35 .32 12.5 ■ 58 .52 .47 .42 15.0 .70 .64 .58 .51 17.5 .8 2 .74 .67 20.0 ■90 .82 .75 .66

Observed values

Interpolated between 12 and IB oz

Although the desired 6 was chosen ini­ the maximum dimension of a fragment de­ tially, certain practical limitations make 6 pends on D, (2) the initial velocity of a only approximately attainable. While the fragment depends, to a slight extent, on values of L and D were set to produce the the shape of the grenade, and (3) low desired 6, L and D also affect other gre­ values of length-to-diameter ratios L/D nade parameters in the following ways: (1) may accentuate end-effect (par. 2—8.4.3.4),

2-13 AMCP 706-240

x l i i /

( a ) s p h e r e (c) CYLINDER R = f R = co

0 = 0 L = D ( b )BARREL SHAPE

FIGURE 2 — 4(U) — PO SSIBLE SHAPES FOR HAND GRENADES 15

which is undesirable. Furthermore, the where maximum diameter and maximum length of the grenade will probably be restricted = solid angle throughout which by the design specification. fragments are projected To determine the optimum shape of a K = a constant = hand grenade casing, consider a set of gre­ nades of equal total weight, and equal C/W ratio. Thus, the explosive weight and the casing weight are fixed, and, to a first approximation, so is the initial fragment At = target area exposed to burst, velocity. Assume that each grenade em­ sq ft ploys con trolled fragm en tatio n (par. Nm = total number of fragments of 2—8.4) and that the number of fragments given mass and the fragment mass are the same for each grenade. Under these conditions and r = distance from point of burst to assumptions, then, only the range of direc­ target, ft tions over which the fragments are pro­ Phk = probability of incapacitation jected will be permitted to vary, while the other initial conditions remain fixed. In this case, the quantity k / Q. is the ex­ From Eqs. 2—2 and 2—3, the probabil­ pected number of incapacitating fragments that will strike the target. Now, assume ity Phk(r) °f obtaining 5-second incapacita­ further that each grenade in the set under tion at distance r can be expressed as consideration is used in the same tactical K situation so that AT and r are fixed, and k is a constant. Based on these and the Phk(D = _ e f t ) ( 2- 12) previous assumptions, Phk(r) will depend

2— 14 AMCP 706-240

K

F ig u r e 2 ~s(u ) — e f f e c t o f s h a p e oh g r e n a d e E ffectiveness 15 only on £2 . Eq. 2— 12 is illustrated in Fig. 2—8.4.1 (U) Notched Coting 2—5 which shows that the probability Older-type fragmentation grenades used Phk(r) of obtaining 5-second incapacitation a cast-iron notched casing to provide frag­ multiplied by the constant ^5 increases with mentation control (Fig. 2—6). This tech­ nique is only partially effective because the the solid angle over which the fragments casing will not reliably break up at the are projected. Therefore, a higher average grooves. Furthermore, it is difficult to effectiveness is obtained by spreading the manufacture a casing of this type that is fragments in space rather than by con­ capable of breaking up into a large number fining them and relying on the chance of of small, high velocity fragments, which is the target being caught in the spray. The a desirable characteristic of fragmentation curve in Figure 2—5 indicates that the grenades. Since this characteristic can be optimum shape for a fragmentation hand more easily produced using other controlled grenade is spherical. The slope indicates fragmentation methods, the notched casing that when k is large, so that £2 / k is small, method is not considered for present-day any increase in £2 is very advantageous. fragmentation grenades. On the other hand, when k is small, so that £2 / k. is large, a small change in £2 is 2—8.4.2(U) Notched Wire or Notched Rings not too important. A notched wire spirally wrapped around a liner, or notched rings fitted over a liner, 2—8.4(U) CONTROLLED FRAGMENTATION provides a reliable method of controlling fragmentation (Fig. 2—7). Whether the Controlled fragmentation provides a notched wire or the notched rings are used, means for controlling the number, size, the liner must be of plastic or thin metal shape, and velocity of grenade fragments. so that it contributes essentially no frag­ Three basic methods for controlling hand ments. It should be as thin as possible, grenade fragmentation are: (1 ) rotated consistent with manufacturing and strength casings, (2 ) notched wire, and (3 ) notched considerations. For laminated phenolic ring. Each type is described in the para­ plastic tubing, a thickness of 5 percent of graphs which follow. its radius has proven satisfactory4.

2-15 AMCP 706-240

can be broken. However, glass tends to pulverize when exposed to the forces of normally acceptable grenade explosives.

At present, steel appears to be the best material for fragmentation. Metals of higher densities than steel are more difficult to form into fragments of the desired mass and shape. Furthermore, for a given weight of explosive, fragments made from these metals cannot be projected as far as steel fragments. Fragments made from metals with lower densities than steel are gen­ erally unsatisfactory because of their rela­ tively low kinetic energy. The steel used to manufacture the notched wire or ring should have a tensile strength of 100,000 to 120,000 psi and should be free from sur­ face cracks and inclusions.

In fragmentation grenade design, notched wire is preferred over notched rings. A fragmentation grenade would re­ quire rings that are too thin for economi­ cal manufacture. Furthermore, it is easier to manufacture the grenade with notched wire than with notched rings.

FIGURE 2 — i(U) — NOTCHED CASING FOR CONTROLLED The dimensions of the wire and the dis­ FRAGMENTATION tance between notches are determined by When selecting the material for frag­ the number of fragments required and the mentation, the ability of the material to desired fragment characteristics. Wire withstand the force of detonation must be dimensions for the M26 fragmentation hand considered. For example, at first glance, grenade, which is the present-day standard glass might appear to be a good material U. S. fragmentation grenade, are shown in because of the sharp pieces into which it Fig. 2—8.

FIGURE 2 — 7(U) — GROOVED WIRE AND GROOVED RINGS FOR CONTROLLED FRAGMENTATI0N 24

2-16 AMCP 706-240

in the theoretical number of fragments should be made to account for these losses.

2—8.4.3.3 IU) Breaking and Chipping of Fragments

No matter what method is used to con­ trol fragment mass, some fragments will FIGURE 2 — 8(U) — NOTCHED WIRE FOR THE M26 break when the grenade detonates. This fragmentation h a n d g r e n a d e 5 breakage reduces the number of incapacita­ ting fragments projected by the grenade. 2—8.4.3(U| Fragmentation Lostoi15 To allow for this breakage, the theoretical number of incapacitating fragments should To compute the probability of incapacita­ tion for any type of fragmentation grenade, be reduced by about 10 to 15 percent to various fragmentation losses must be con­ determine the actual number of incapacita­ sidered. These losses reduce the actual ting fragments. effectiveness of the grenade to a level less than its theoretical "optimum” effective­ The corners and edges of some of the ness. Optimum effectiveness means the projected incapacitating fragments will chip effectiveness that could be obtained if the when the grenade detonates. Chipping re­ grenade had no fuze, if the casing were duces the weight of a projected fragment perfectly packed with fragments, and if the to a value below the value before projec­ projected fragments retained their original tion, thereby slightly reducing the proba­ mass and shape. The losses that result bility of incapacitation. However, this from each of these factors are discussed weight loss for rectangular parallelepiped in the paragraphs which follow. steel fragments is of the order of 5 to 10 percent, and can usually be ignored.

2—8.4.3.1 (U) Fuze Volume 2—8.4.3.4(11) Closing Cap Losses A fuze occupies space that could other­ On barrel-shaped and spherical frag­ wise be occupied by explosives or frag­ ments. A typical fragmentation hand gre­ mentation grenades, the end opposite the fuze has a hole through which the explo­ nade fuze has a volume of 1.5 to 2.0 in. sive charge is cast. To prevent a blind This volume must be deducted from the spot in the fragment spray for this end of maximum explosive volume to allow for the the grenade, the closing cap should be de­ presence of the fuze. The initial fragment signed so that it projects fragments when velocity, therefore, must also be reduced the grenade bursts. The cap should be because of the reduction in explosive vol­ ume. made from a tough steel, and notched on the inside surface (explosive side). The Another deduction must be made for the notches should be spaced so that the frag­ fragments displaced by the fuze. On the ments projected by the cap are of the same assumption that the fuze contributes no weight as those projected from the gre­ effective fragments, the void in the frag­ nade casing. ment spray is 5 to 15 percent, depending upon the particular type of casing and fuze. 2—8.5(U) EFFECTIVENESS OF VARIOUS GRENADE D E S IG N S 15 2—8.4.3.2 (U) Pocking lasses The paragraphs which follow compare The actual number of fragments ob­ the relative effectiveness of various theo­ tained from a notched wire wrapping (par. retical grenade designs. The probability of 2—8.4.2) will be less than the optimum incapacitation quoted are based on older theoretical number. The loss in fragments wound ballistic data, which have been is caused by imperfect packing or wrap­ superseded by more precise data (see par. ping. Typically, a reduction of 10 percent 2—6.1.1). While the individual values of AMCP 706-240

Pk are not precise, they permit a compari­ has essentially no effect on Pk(r). For ex­ son of the effectiveness of different size ample, at zero burst distance, P k(r) would grenades employing various values of equal 1 for any shape grenade. For this charge-to-weight ratio C/W, and fragment discussion, then, only burst distances of 5 weights. ft or more are considered. The higher the value of Pk(r) for a 2—8.5.1 (U) Overall Probability of Incapacitation spherical grenade, the greater will be the loss in Pk(r) by changing to a b a rrel­ The probability that a hand grenade will shaped grenade. This is so because the incapacitate a point target depends upon slope of the P k(0 curve in Figure 2—5 is the probability of incapacitation at a cer­ greatest for low values of Cl / K and, con­ tain burst distance from the target and the sequently, for large values of K. Now, as­ probability of achieving that burst distance. sume that this grenade is changed to the If Pk(r) is the probability of 5-sec incapac­ barrel shape shown in Fig. 2— 9 and that itation at burst distance r, and if P(r) is there is no contribution of fragments from the probability that a thrown grenade will the fuze end or the end opposite the fuze. burst within distance r of the target, then Then, the probability Pk that a thrown hand gre­ nade will incapacitate a point target within ^ = -707 x 4tt „ o 4 4 4 5 sec is: K 20 ' ’

n oa and the value of 4tt Pk(r) will be 0.40. Pk = Pk(r) J J llll dr (2— 13) T Jo dr Therefore, the change from a spherical to a barrel-shaped grenade has resulted in a Values of r greater than 15 ft do not con­ 20 percent reduction in Pk(r) at the 5-ft tribute appreciably to the integral for the burst position. following reasons: (1 ) Pk(r) is nearly zero Evaluating the above results in a more at 15 ft or more; (2 ) the vast majority of practical sense, however, indicates that the bursts are within 15 ft, so that at 15 ft difference in Pk(r) will be less them 20 per­ P(r) is nearly at its maximum and limiting cent. This is because a spherical grenade value of unity. must also employ a fuze and because frag­ ments projected from the end opposite the 2—8.5.2(11) Spherical Versus Barrel-shaped Grenades f PIGMENT SpRAy^

Barrel-shaped grenades, particularly the wire-wrapped type, are generally easier ’ j J - t - U / to make than a spherical grenade. How­ ever, a barrel-shaped grenade has the dis­ advantage of leaving voids in the fragmen­ tation pattern. The difference in Pk(r) between a barrel­ shaped grenade for which 6 equals about 45° or less and a spherical grenade of equal weight C/W and fragment weight is greater for heavier grenades and for . ! I shorter burst distances. However, this is SPR^ not true for very short burst distances, FIGURE 2- -9(U) — APPROXIMATE FRAGMENTATION such as those up to a few feet, because at PATTERN FOR A BARREL-SHAPED these distances the shape of the grenade GRENADE 15

2 - 1 8 AMCP 706-240 fuze (par. 2—8.4.4.4) will contribute to the PULL RING ASSEMBLY PRIMES Pk(r) of the barrel-shaped grenade. For PRIMER HOLDER the 18-oz (fuzed) spherical grenade, it is ASSEMBLY estimated that a change to barrel shape will result in about an 8 percent reduction in P k(r) at 5 ft; for the 15-oz and 9-oz gre­ nades, the estimated reduction is about 4 percent and 2 percent, respectively. At the 10- and 15-ft burst positions, the reductions are considerably less. The barrel-shaped grenade, then, may be considered slightly less effective than the spherical grenade at the 5-ft burst distances, and about as effec­ tive at the 10- and 15-ft burst distances.

2—9 (U) FUZING

Generally, three basic types of fuzing have been considered for fragmentation grenades: (1) proximity fuzing, (2) pyro­ technic time delay fuzing, and (3 ) impact fuzing. Each is discussed in the paragraphs which follow.

2—9.1 (U) PROXIMITY FUZING

The most effective fragmentation hand grenade is one that detonates above the ground and projects its fragments in all F ig u r e 2 — io(W — T y p i c a l pyrotechnic T im e directions below the horizontal. A grenade d e l a y f u z e of this type requires some type of proximity of fuze employs a delay column of slow- fuze to sense the proper burst height and burning powder that is ignited when the detonate the grenade at that height. grenade is released by the thrower. The Furthermore, a suitable grenade configura­ column requires a fixed time to burn tion and some method of orienting the gre­ through, which is typically about 4.5 to 5 nade in a particular direction at the time sec, and at the expiration of this delay time of burst are required. Both of these require­ it fires the detonator. ments increase the cost, weight, and com­ plexity of the grenade. These factors off­ Fragmentation grenades employing set the greater effectiveness of proximity pyrotechnic time delay fuzes have proven fuzing when compared to other grenade acceptable to the military, and their cost fuzing methods. Therefore, a proximity fuze is low compared to the cost of grenades has never been used in any past or pres­ employing other fuzing techniques. How­ ent-day fragmentation hand grenades, and ever, grenades of this type have a number there is little, if any, current effort to of tactical limitations due to the time delay develop one. element, the most important of which are: (1) an enemy might be able to take cover 2—9.2(U) PYROTECHNIC TIME DELAY FUZING before the grenade detonates, (2 ) the gre­ nade might roll back downhill and detonate The pyrotechnic time delay fuze (Fig. near friendly personnel, and (3 ) the gre­ 2— 10) is, by far, the type used most often nade might be picked up and thrown back for fragmentation hand grenades. This type by an enemy.

zes-sn O - 6s - 5 2 - 1 9 AMCP 706-240

Mechanical, electrical, and chemical de­ functions accidentally, it cannot initiate the vices might be incorporated into a grenade next explosive train component. This can fuze to provide the required time delay. be accomplished by using an out-of-line However, these devices all possess the detonator that rotates into place when the same tactical disadvantages listed above fuze undergoes a high setback force. Or, and, in addition, are more expensive to an interrupter, which forms a physical bar­ produce than the pyrotechnic time delay rier between the detonator and the next fuze. explosive train component, can be moved out of the way when the fuze undergoes Although present-day fragmentation setback or some other force associated with hand grenades employ pyrotechnic time launch or flight. delay fuzes almost exclusively, there are many military applications in which impact Since hand grenades experience no fuzing techniques are desirable (par. unique forces that can be used to perform 2—9.3). the functions described above, the detona­ tor safe requirement has been waived for Broadly, the pyrotechnic time delay fuze past and present-day hand grenade fuzes. consists of an explosive train, safety and arming devices, and a striker assembly. Actually, hand grenades can be designed The explosive train is discussed in par. so that they are detonator safe. An out-of­ 2— 10. Actually, the fuze does not contain line detonator can be moved into place or the complete explosive train; the main an interrupter moved out of the way by the charge is contained in the grenade casing. thrower just prior to throwing the grenade. Or, a small electric motor can be used to 2—9.2.1 (U) Safety and Arming accomplish either of these functions after the grenade is thrown. These approaches Ideally, an ammunition item should arm are difficult, however, because of the size only when it experiences forces unique to and weight limitations imposed on hand the launch environment. At all other times grenades. — i. e., during storage, transportation, and While the detonator safe requirement handling— the fuze should remain safe (un­ has been waived for existing hand gre­ armed). Most ammunition items do experi­ nades, it is desirable that a practical deU ence unique forces at the time of launch. onator safe device be incorporated into For example, a projectile experiences a future fuze designs. Some type of device very high setback force when it is fired requiring both automatic and manual oper­ from a gun. It may also experience a very ation during the arming-throwing cycle is high rate of spin. The forces resulting from preferred, provided the device is practical, both setback and spin can be used to cause inexpensive, and does not detract from the fuze to arm. Similarly, missiles and the tactical use or effectiveness of a hand rockets experience high acceleration forces grenade. after they are launched, which may be used to cause the fuze to arm. Since there are no unique forces asso­ ciated with the launch or flight of a hand Unfortunately, a hand grenade does not grenade that may be used for arming, arm­ experience any unique forces at the time it ing must occur as the result of some action is thrown, or launched, or while it is in or event prior to the time the grenade is flight. Therefore, arming must occur as a thrown. To date, the best method of accom­ result of some action or event prior to the plishing this is to have the thrower perform time the grenade is thrown. some positive action that will cause the Certain other problems arise in the de­ fuze to arm. In Fig. 2— 10, the firing pin is sign of safety and arming devices for hand restrained by the safety lever. The safety grenades. A mandatory requirement for lever, in turn, is restrained at one end by fuzes is that they must be "detonator safe.” the pull ring assembly, which is simply a Detonator safe means that if the detonator cotter pin attached to a metal ring, and

2 - 2 0 AM CP 706-240 by a T-lug at the other end (Fig. 2— 11). purposes. To ensure this low probability, The faze becomes armed when the thrower, the reliability of the delay column must be while holding the lever in place, pulls the such that short burning times are very safety pin out of the fuze body. Only the improbable. A reliable delay column, by pressure of the thrower’s hand holding the itself, will not ensure a low probability of safety lever on the fuze prevents the fuze premature function. The reliability is also from functioning. When the grenade is dependent upon the design and construc­ thrown, the lever is released and is forced tion of other fuze components, and the de­ out and away from the grenade body by sign and construction of the fuze housing the striker. The striker continues moving itself. For example, a combination of exces­ In an arc and hits the primer, thereby sively porous fuze castings and cracked or initiating the fuze. leaky detonator cups in M26 fragmenta­ tion grenades was believed to have been The use of a lever and a pull ring assem­ the cause of a number of premature func­ bly to provide safety is typical of almost all tions ,8. The primer output flash broke U. S. and foreign hand grenades. However, through the porous casting, bypassed the at least one foreign grenade uses a third delay column, and initiated the cracked device, a wire ring around the head of the detonator (Fig. 2— 12). Thus, grenade det­ fuze and the lever, to prevent the lever onation occurred after essentially zero time from moving17. While this device provides delay. additional safety, removing the ring creates an additional operation that the thrower must perform before throwing the grenade. 2—9.2.2(U) Striker Assembly 19 Another major safety requirement for a The striker assembly used in almost all hand grenade is that the probability of a present-day hand grenades consists basi­ premature function after the grenade is cally of a firing pin attached to a torsion- thrown must be ideally zero for all practical type wire coil spring (Fig. 2— 10). When a grenade is assem bled, the firing pin is cocked, which winds the spring. The spring force F is equal to

FUZE F = EIa SAFETY corns PIN 2: where

E = Young’s modulus of elasticity, SAFETY PIN psi PULL RING 2 = length of spring, in. r - lever arm of force F, in. 0 = angular displacement of coil, rad IA = second moment of cross-sec- tiongil area, in.4, which can be expressed as s a f e t y l e v e r nd*4 "ST"

FIGURE 2 — I HU)— SAFETY LEVER AND PULL RING ASSEMBLY where d - diameter of wire, in.

2-21 AMCP 706-240

Typical spring dimensions might be: i - 0.50 in.; r = 0.50 in.; dw = 0.035 in.; E = 30 x 106 psi; and 0 = rr rad. There­ fore,

IA = n(Q' = 0.073 x 10'6 in.4 64 and

f _ (30 x 10^) (0.073 x 10-^) r =2glb (0.5) (0.5)

Fragmentation hand grenades almost always use percussion-type primers (par. 2— 10.2.1.1). The energy needed to initiate the percussion primer is obtained from the potential energy Hs stored in the spring and released when the striker swings. This potential energy can be expressed as:

FIGURE 2— l2(U) — ONE CAUSE OF PREIAATURE FUNCTION IN HAND CREN AO E18

2-9.3 (U) IMPACT FUZING where The primary disadvantages of the pyro­ technic time delay fuze (par. 2—9.2) can G = the torque that is proportional be overcome by using an impact fuze. How­ to deflection ( = k 6) ever, impact fuzes are more complex and k = spring constant, lb/rad more expensive, and, therefore, have not replaced pyrotechnic time delay fuzes for r = radius arm of the striker that general use. swings through rr radians The only current U. S. fragmentation Since r = 0.5 in. and k = -^lb/rad, hand grenade fuze employing impact func­ then tion is the M217 electric fuze which is de­ signed for use with the M26 grenade. The Hs = 7 it lb-in. = 352 in.-oz M217 fuze includes both an impact function and an overriding time delay function. The If we assume that the striker assembly is time delay function in the M217 fuze, like only 50 percent efficient because of friction, that in the pyrotechnic time delay fuze, is the energy available as the striker hits the produced by initiating incendiary material. primer is 176 in.-oz. However, in the M217, the delay function occurs due to heat transfer through solid Since obturated fuzes are preferred for thermal barriers; incendiary flash transfer fragmentation hand grenades (par. 2— 10), does not occur. the firing pin must not puncture or rupture the primer cup at the time of striker im­ The M217 fuze is shown in Fig. 2— 13. pact. Therefore, a blunt firing pin must be It consists essentially of a power supply used. A typical firing pin radius is about (thermal battery), an omnidirectional im­ 0.050 in. However, tests on flat firing pins pact switch, an electric detonator, a fusible- and pins with a radius up to 0.023 in. indi­ link arming delay switch, and a fusible-link cate that the radius has little effect on self-destruction switch. The arming se­ firing pin sensitivity 20. quence is as follows:

2 - 2 2 AMCP 706-240

M26 HAND GRENADE

SELF-DESTRUCTION SWITCH IMPACT SWITCH

T44 ELECTRIC DETONATOR TETRYL BOOSTER

0OUCHON ASSEMBLY POWER SUPPLY

FIGURE 2 — 13(U)— M2J7 ELECTRIC FUZE 2)

(a ) When the grenade is thrown, the sec to complete the circuit from the power striker assembly (par. 2—9.2.2) initiates supply to the detonator. The self-destruc­ the percussion primer. tion switch, like the arming switch, is (b ) The percussion primer, in turn, thermally activated by the heat from the thermal power supply. ignites a fast-burning pyrotechnic mixture of metal and oxidizer which raises the tem­ The purpose of the 1.5-sec arming delay perature of the thermal power supply to its is to assure that the grenade is a safe dis­ actuation point within about 0.5 sec. tance from the thrower (about 60 ft) be­ fore detonation can occur. This arming de­ (c ) Heat generated by the power sup­ lay also prevents immediate impact func­ ply then actuates the thermal arming tion if the thrower accidentally drops the switch about 1.5 sec after the grenade is grenade after withdrawing the safety pin. thrown. This completes the arming process. A dropped grenade will strike the ground After arming is completed, any impact in about 0.5 sec, which is less than the of the grenade that is equivaient to the arming delay time, so that impact function impact resulting from a 6-in. drop on a cannot occur. Since the self-destruction hard surface will close the impact switch switch does not close for about 4.5 sec, the and complete the circuit from the power thrower will usually have time to take supply to the electric detonator, thereby cover, or to pick up and throw the armed causing the grenade to function. If no im­ grenade. However, if a dropped grenade pact occurs, or if the impact is too weak should roll and strike a hard object, impact to close the impact switch, the self-destruc­ function can occur at any time after the tion switch (Fig. 2— 14), which bypasses arming delay period and before self­ the impact switch, closes after about 4.5 destruction occurs.

2— 23 AMCP 706-240

FIG U RE 2 — 14(U) — E L E C T R IC A L CIRCUIT OF THE M217 F U Z E 2'

2—9.3.1 (U) Impact Switches arranged that no matter what the orienta­ tion of the grenade at impact, at least two Since the orientation of a hand grenade or three of the balls will be accelerated at the time of impact cannot be predicted, toward the axis of the switch. The ball an omnidirectional impact switch must be forces the end of the adjacent leaf spring used. Ideally, the sensitivity of the switch through a small air gap so that the leaf should be such that the grenade will det­ spring contacts the center contact. Because onate upon impact with even the very soft­ of flexure of the spring after contact, the est type of terrain, such as very soft snow. duration of closure is extended beyond the However, the maximum sensitivity of the period of deceleration. This characteristic switch is limited by the following factors: of switch operation is very important be­ (1) the sensitivity must be low enough to cause it reduces contact chatter, and ex­ permit the grenade to fly through light tends closure time for impacts of very short foliage without switch closure occurring, duration. (2) the switch must not close should it be­ come necessary to throw an armed gre­ nade, and (3) the switch must not close when subjected to centrifugal forces devel­ 2—9.3.2(U) Thermal Switches23 oped by spinning the grenade about any Thermal switches close (or open) elec­ axis when the grenade is thrown. Based on trical circuits when the switch reaches a these factors, the M217 fuze uses an impact certain temperature. Of the various types switch having a maximum sensitivity of 35 of thermal switches, the fusible-link type g. This provides sufficient sensitivity to appears to be the most suitable for pro­ cause impact function on almost any ter­ viding electrical time delays in grenades. rain, except very soft snow, following a Fusible-link thermal switches are small, flight of the grenade that is long enough to rugged, reliable, and relatively inexpen­ assure that the fuze has armed. sive. There is little switch-to-switch vari­ The M217 fuze uses a trembler switch ation in the tem perature at which the of the type shown in Fig. 2— 15 to provide switch closes. Furthermore, unlike many impact capability. In its simplest form, a bimetallic-type thermal switches, fusible- trembler switch is a mass-spring combina­ link type thermal switches do not require tion enclosed in a case. Upon impact with individual calibration and adjustment. the ground, deceleration forces cause the Fig. 2— 16 shows the fusible-link thermal mass to deflect the spring so that the switch used to provide the arming delay spring makes contact with the case or in the M217 impact fuze. It is activated by other switch element to close an electrical the heat from the thermal battery, and circuit. closes in about 1.5 sec after the thermal The switch shown in Fig. 2— 15 uses battery is initiated. A cadmium-lead-zinc steel balls (g-weights) which, upon deceler­ alloy disk with a melting point of about ation of the grenade at impact, deflect leaf 280 °F and a perforated Fiberglas disk are springs that serve as contacts. Eight mass­ sandwiched between the two switch con­ spring combinations in the switch are so tacts. When the alloy disk melts, molten

2 - 2 4 AMCP 706-240

SLEEVE

MASHER

-.065 MAX.

/ / / / STOP RING / / / L— BALL WEIGHT / / 1— CONNECTOR

' ^-CONTACT SPRING

SWITCH HOUSING

FIGURE 2 — 1S(U) — TftE/HflLER-TVP£ IMPACT SWITCH 22

HEAT SOURCE AND CONTACT More uniform and more reliable switch loading can be obtained by spring loading one of the switch contacts. The spring- loaded switch shown in Fig. 2— 17 provides the 4.5-sec self-destruction delay for the M217 impact fuze. The thermally activated element of this switch Is a pressed pellet of mercuric iodide which melts at about 500 °F. When the pellet melts, the spring- loaded contact firmly presses against the other contact, thereby reducing the con- tact resistance of the closed switch to a few hundredths of an ohm. OPEN POSITION CLOSED POSITION

FIG U RE 2 — 1MU) — FUSIBLE-LISIK THERMAL SWITCH 23 2—9 .3 .3 (U) Thermol BalM ries

A thermal battery is basically a primary voltaic cell (or combination of cells) having metal flows through the holes in the Fiber- a positive electrode, a negative electrode, glas disk, thereby bridging the gap between a solid electrolyte, and a heat source. When the contacts and closing the switch. the electrolyte is heated to about 275° F

2 - 2 5 AMCP 706-240

CONTACT TEMPERATURE SENSITIVE ELEM ENT

i T

OPEN POSITION

FIGURE 1 — n (U ) — SPRING-LOADED FUSI&LE-LIHK THERMAL SWITCH^

or higher, it melts and becomes a liquid 2—9.3.4(11) Electric Detonator! ionic conductor. The most common way to The designer is referred to Reference 1 provide heat is to surround the cell (or for a detailed discussion of various types cells) with a pyrotechnic material. of electrical detonators. However, the de­ A thermal battery for hand gTenades signer must keep in mind the need for need only provide sufficient energy to fire proper shielding to prevent accidental initi­ an electric detonator. Therefore, a battery ation of the detonator by stray electro­ with a low output voltage and relatively magnetic fields. For example, in the M217 low current, and having a short active life, fuze, all electrical components, including can be used. For example, in the M217 the electric detonator, are contained in a fuze, the electric detonator is initiated by hermetically solder-sealed metal can. This a single cell (1.5 volts) having an active can provides shielding against electromag­ life of about 15 to 20 sec. The battery is netic and electrostatic discharge, as well only about 0.5 in. long and 0.5 in. in diam­ as protection against moisture. eter. It is simply, and reliably, initiated by a percussion primer. Thermal batteries will perform satisfac­ 2—10 (U) EXPLOSIVE TRAINS torily over the temperature range normally Explosive trains are covered in detail specified for grenades, and can meet the in Reference 1. The reader is referred to shock and vibration requirements specified that reference for a detailed discussion of for grenades. explosive train design techniques. Addi­ The minimum shelf life of a thermal bat­ tional information is given in Reference 20 tery is about 15 yr. Since the action of the and References 24 through 28. The para­ heat source is irreversible, thermal bat­ graphs which follow briefly discuss some teries cannot be tested during storage, of the important characteristics of explo­ which is probably their main disadvantage. sive trains, explosives, and components.

2-26 AMCP 706-240

An explosive train is an assembly of explosives. A primary high explosive is explosive elements arranged in order of characterized by its extreme sensitivity to decreasing sensitivity. Its purpose is to heat and shock. It is capable of building amplify a low-level impulse to a level high up from a deflagration to detonation in a enough to detonate the main charge of a short distance and time; it can also propa­ munition. A typical explosive train for a gate a detonation wave in a very small pyrotechnic delay (par. 2— 9.2) fragmenta­ diameter column. Typical materials classi­ tion hand grenade consists of a primer, fied as primary high explosives sire lead delay element, relay, detonator, and the azide, lead styphnate, and diazodinitro- main charge (Fig. 2— 18). When the primer phenol (D D N P). Primary high explosives is struck by the grenade firing pin, it initi­ are normally used to detonate secondary ates, and, in turn, ignites the delay ele­ high explosives. ment. The delay element provides the time A secondary high explosive is not needed for the grenade to reach the target. readily initiated by heat and shock. Nor­ The delay element, after burning through, mally, a secondary high explosive must be fires the relay. (In most fragmentation initiated by a primary high explosive. Typi­ grenade explosive trains, the relay is sim­ cal materials classified as secondary high ply the last charge increment in the delay explosives are PETN, RDX, and Composi­ element.) The relay amplifies the relatively tion B. weak impulse from the delay element to a level high enough to fire the detonator The most important characteristics of a which sets off the main charge. high explosive are: (1 ) sensitivity, (2 ) sta­ bility, (3 ) brisance, (4) detonation rate, 2— 10.1 (U) EXPLOSIVES and (5) compatibility with other materials. Values of (1 ) through (4 ) for typical ex­ High explosives may be classified as plosives now in use or being developed are primary high explosives and secondary high given in Table 2—4. The compatibility of these explosives with various materials is given in Table 2— 5. The compatibility of the explosives with metals, unless other­ wise noted, represents the effect of the explosive in contact with the metals after being tested at ambient temperature for two years.

2— 10.2(LI) EXPLOSIVE TRAIN COM PONENTS

Design considerations for explosive train components are discussed in detail in Ref­ erence 1. These considerations are re­ viewed briefly here with respect to frag­ mentation hand grenades.

2—10.2.1 (U) Primorj A primer is a relatively small, sensitive explosive component used as the first ele­ ment of an explosive train. As such, it con­ verts mechanical (or electrical) energy into explosive energy. Primers may be classified according to FIGURE 2 — 78(l/J— ELEMENTS OF A TYPICAL fragmentation h a n d g r e n a d e the way they are initiated — i.e., percus­ e x p l o s i v e t r a in sion primers, stab primers, and electric iviiNaaidNOD V - 20 E t a l a v a C 5 8000 6000 9200 O- 9200 00 • '3 19

.K 1.06 1 3 * * c c 0 J? “ Ife

2 - 10 Bl»*t tij|hu 1 (B*»c ul . . Ch*fjjcl 4 u i « V — v > s. n 0 6 u 1,13 1.00 E^ui v alenr alenr v E^ui 0 0 17 _1 c * * a* r - L ■0 "® Jc I P rr**rd P Pressed Pttijfrf Pressed Pressed C«ii C*»t sed Pres Cast C»*t 16 .94 a C L L 1-73 1-63 1.77 1,81 u ji y ji 1 71 37 Den Den IS 6 a

Z "3 1.81 1.65 1 1,54 1 1.51 1.62 1.61 14 § c 0 V "a Z A 7000 7680 7375 7342 8400 8190 6790 a a 0 I

) « !0 s 3 ocol 1 « c 0 3 a 7040 7310 8300 6180 6240 7300 6970 , 5 2

.5 IU - ~ 0 2 12 a is - a a c S 0 t j ■ g-U | J I £ £ K *!., *!., 5 - v a ­ 1 25 11 100 130 157 L 121 173 a > a 21 - <=i 1 Power >0 10 45 34 l £

1 L 150 l 100 116 d X d z 120 P> ^i­ F- CO m 3 n 0 9 -0 -0

v ; 9 ?-g *Q V 3 54.0 54.2 53-2 59.3 0 “ <5 iX) 62.7 60.2 583 48,0 62,1 16 16 2 8 .B s-c 1.40 1.68 g | 2.33 2,01 0 7 £ 1,55 1-69 1.58 1.60 I 1.34 [nit iatioo by iatioo [nit Sensitivity Sensitivity Tettyl Boosier Tettyl a * 1 0 1 -0 6 D F D D D 7

. B, . B, . , SJ 0 * oV 278 320 32 330 223 260 273 237 475 l i * HJH w HJH 3 ______U U u u u u u | UL u

'Z U. jr jr

. s s c l c 0 6 C ■0 T ,£ T 4 J> t» U U u u E u E c c 1 U> Sensitivity - 3 « « e So a h —. h —. X : » £ 30 26 17 75 33 28 17 100 Teat 2 6 8 8 N * Impact 14 17 v „ L- 11 11 14 LO > 1 i- J i £5 0 0

O O O 2

43 43.2 60,8 42,3 44.6 Was N. N. N. N. N. N. N, N, N. N. \ 6

7.7 18.3 37 24.4 37.9 1 TNT TNT RDX. RDX. H. H. 30 H. H. K, L K, H. H. H. H. 23 3 60 1.7 2-2 2.7 2,3 2.7 Composition, % Composition, C, C, C. C. C. C. C. C. 0 J C. J C.

TetryK TetryK KMX. TNT. TNT. RDX, RDX, TABLE 2-4(0. CHARACTERISTICS OF MILITARY EXPLOSIVES33 6.3 L 39 19 16.2 70 73 29 37.0 97 B B A 39 3742

87 3 21723 21723 13738 401 00398 -248 -45444 -043443 Go*«»inj L-R- 1 SpcciHciiiDn J A N ■ T ■ ■ T ■ N A J MIL-R MIL-R MIL-R-L MIL-R JAN-T MILH MIL Ml L-C- Ml MIL-P-J M NOTES t ' Tti«»tro- a m i rve i m a 6 (• , , 4 Chemical Name Chemical , , Ti i (\i (\i i Ti 2 Phenylrarlhyl ettanutamtoe T Pcntaerythtitol Trinitrotoluene C ycloft imeihylefie T(dlAll'kl imeihylefie ycloft C amohylenc Cyclotett ' IgflltCS NiinmiAr * ' Tamped, Crystalline TNT TNT Crystalline * ' Tamped, Decompose* ■ D 1 97/3

70/30 »cklc* »cklc* - Unaffected U m 75/25 0 Eiplalivf E ■ Eiplodci Eiplodci ■ E f!*n«l ■ F erratically C ■ ■ C HHX

TABLE 2~5(U). COMPATIBILITY OF HIGH EXPLOSIVES WITH METALS AND OTHER MATERIALS 1

Brass Steel N. Material O O -O C l a 0 "O ^ c cu Li •A N w O E = V d a 2 Explosive cC

£ Shellac coated Magnesium

< fXi Copper plated z Cadmium plated CL Sd CL (Z -O P 5 % u a

\ w W w W W w W W w w w V w V

Amatol 50/50 Sm vsm Fm Hmt VHm C„3 Hm Cm Hm Fm Fm

Mercury fulminate Fm F m Fm Fm Fm Fmt Fm Fm Fm Fm

Pentolite Fm v sm Sm* F m Fm VSm Fm Fm Fm Picric acid Fm Fm Sm Fm Fm Fmt Sm Fm v sm Fm Fm Tetrytol 65/35 Fra

Tetrytol 75/25 Fm VSm Js m * VSm vsm VSm Sm Fm Fm

Black powder Hra Hm Fm Fm Fm* Hm F mt VHm Sm F m Fm F m

Composition A~3 Fm Sm Sm* Sm Fm Sm Sm Fm Fm

Composition B Fm Sm Sm vsm VSm Sm Sm Fm Fm M@100<’ F m Uel20“ — U,012O» M^fJO*

Explosive D Fm Fm Fm Fm Cm Fmt VSm Fm Sm Fm Fm Lead azide Fmt Pm Pm Pm rF m * P VSm

PETN VSm vsm Sm* VSm vsm Fm VSm Fm Fm

Picratol 52/48

RDX F m Fm Fm F id Fm Fmt v sm Fm Fm Fm Fm

Tetryl F m Fm F m Fm Cm F mt F m Fm Fm Fm Fm

Tet/ytol 70/30 Fm

TNT Fm Fm Fm F m Hro* Fm v smr v s m Fm Fm Fm Fm M

Tritonal 80/20 M

t 10 months t 12 months *18 months

Legend

F = favorable, no visible 11 = heavy corrosion M = moderate reaction evidence of corrosion VH = very heavy corrosion U rc undesirable reaction VS = very slight corrosion, C - considerable corrosion, W = wet sample indicaied by light tarnishing indicated by pitting or rusting Subscript m - explosive rC' S = slight corrosion, indicated by P = prohibited action on metal heavy tarnishing

2 - 2 9 AMCP 706-240 primers. Of the three, the percussion The output end of a percussion primer primer is the only type used in a fragmen­ is not sealed. The explosive is retained in tation hand grenade. the cup by a thin paper or metal cover. The physical construction of a percus­ 2— 10.2. U fU) Percussion Primers sion primer can affect primer sensitivity in the following ways: To ensure reliable delay element burn­ ing time, a grenade fuze must be obturated a. Cup Thickness. Primer sensitivity de­ (sealed) to prevent the escape of gases creases as the thickness of the cup during burning (par. 2— 10.2.3). To main­ increases. tain this gas-tight seal, the firing pin must b. Cover Thickness. Primer sensitivity not puncture or rupture the primer con­ decreases as the thickness of the tainer when it strikes the container. A cover increases. percussion primer, initiated by the impact of a blunt firing pin, provides a simple and c. Anvil Movement. The anvil must be reliable method of meeting this require­ firmly attached. Any movement of ment. the anvil can drastically reduce the sensitivity to the firing pin action, 2— 1 0 .2 .1.2 IU) Percussion Primer Construction yet increase the sensitivity to shock and vibration. A typical percussion primer consists of a cup, a thin layer of priming mix, a dos­ d. Excentric Firing Pin Impact. Sensi­ ing disk (cover), and an anvil (Fig. 2— 19). tivity is reduced for this type of im­ Initiation occurs when the blunt firing pin pact. pinches the priming mix between the cup Firing pin requirements are discussed in and anvil. The output of a percussion par. 2—9.2.2. primer is usually a flash or spit of flame, and is seldom a detonation. Loading pressure does not appreciably affect the input requirements of percussion The primer cup should be constructed primers. There is, of course, a direct rela­ of a ductile metal so that it will not rup­ tionship between the amount of explosive ture when it is struck by the firing pin. charge and the primer output. Brass is a common metal used for cups. Reference 28 describes design practices 2— 10.2.1.3 fU) Priming Compositions and specifies the standard dimensions, tol­ erances, materials, and finishes for primer Table 2—6 lists the composition of com­ cups. In general, all designs and construc­ mon priming mixtures used by the military. tion should conform with Reference 28. The ingredients are given for seven stand­ However, it is not the intent of this refer­ ard primer compositions. ence to inhibit the development of new concepts; occasional departures from the 2— 10.2.2(11) Detonators prescribed practices may be necessary under special circumstances. A detonator is a small, sensitive compo­ nent that can initiate a high-order detona­ tion in the next high explosive component of the train. In the case of the fragmenta­ tion grenade, the detonator fires the main charge (or the booster charge if one is used). A detonator is similar to a primer, except that its output is a detonation wave instead of a flame. Detonators are classified according to FIGURE 2~ I9(U I — TYPICAL PERCUSSION PRIMER 19 the way they are initiated — i.e., flash

2—30 AMCP 706-240

TABLE 2-6(U). COMMON PRIMING COMPOSITIONS1

Composition (pereent by weight) Ingredient s 'FA70 'FA90 ^AlO O 2PA101 795 3NOL60 JNOL 130

Lead Styphnate, Basic — — 53 39 60 40 Lead Siyphnaie, Normal - - 38 - - - - Barium Nitrate - - 39 22 44 25 20 Lead Azide - - - - - — 20 Tetracene - 2 5 2 5 5 Lead Dioxide - - 5 — — — — Calcium Siliclde - - 11 - 14 — — Aluminum Powder - — — 10 - — — Antimony Sulfide 17 12 5 10 - 10 15 Lead Sulphoeyanate 25 25 - - - - - PETN - 10 - — - - - TNT 5 - - — - - - Potassium Chlorace 52 53 — - - - -

l FA - Frankford Arsenal

3PA = Picatinny Arsenal

3NOL - Naval Ordnance Laboratory

detonators, stab detonators, and electric detonators. Of the three, flash detonators are used the most in fragmentation hand grenade design. O u t p u t 2— 10.2.2.1 (U) Flash Detonators End

Flash detonators are sensitive to heat. When they are initiated, a detonation wave is created at the output. Detonators for fragmentation grenades are initiated by heat from the delay element (par. 2— 10.2.2). Output End A typical detonator consists of a cup; primary, intermediate, and base charges; and closing disks (Fig. 2—2 0 (A )). The pri­ mary charge is located at the input of the detonator, and the base charge is located (B) Ml7 at the output. Usually, in a flash detona­ tor, the primary and intermediate charges f i g u r e 2 — 2o( u) — t y p i c a l f l a s h d eto n ato r s 19 are combined so that, in effect, the detona­ tor contains only two charges (Fig. 2—2 0 (B )). Aluminum and stainless steel are good cup materials for flash detonators. Gilding The closing disks may be of metal or of metal is also satisfactory, though it is not paper. Both the material and the thickness used for flash detonator cups as often as of the material used to seal the input end aluminum and stainless steel. of the cup affect primer sensitivity. AM CP 706-240

2— 10.2.2.2 (U) Explosives for Detonators tive output. In general, this includes the base charge and part of the primary Most flash detonators contain only a pri­ charge. Where the primary charge is mary charge and a base charge, although dextrinated lead azide, the portion that in the past most also contained an inter­ detonates high-order can vary appreciably mediate charge (Fig. 2—20). Since the with loading density, confinement, and lot­ trend is toward detonators containing two to-lot variations in the lead azide. The azide charges, only those types are discussed that actually detonates must be sufficient here. to initiate the base charge. A rule of thumb a. Primary Charge. Primary high ex­ calls for a 0.10-in. minimum column height. plosives (par. 2— 10.1) are used as the The growth of detonation is most rapid primary charge. The properties that pro­ in explosives loaded at densities well below mote the growth of detonation have not those usually used in military applications. been quantitatively defined. However, lead But, the effective output of stable det­ azide appears to be so superior to other onating explosives increases sharply with explosives that it is the only one used in density. Therefore, a given quantity of ex­ current fuze detonators (excluding bridge- plosive charge has a maximum effective wire applications). At first glance, certain output at a particular optimum density. other explosives might appear to be as This optimum density is affected by the suitable as, or even superior to, lead azide; composition and particle size of the explo­ but on close analysis, lead azide has better sive, the energy with which it is initiated, overall characteristics in this application. and the dimensions and confinement of the The fact that flash detonators are ignited explosive. For conditions usually encoun­ by rather diffusely distributed heat might tered in designing detonators for fuzes, the lead to the conclusion that such explosives optimum density for dextrinated lead azide as tetryl and PETN, which have relatively and normally used base charge explosives low ignition temperatures, would be effec­ is obtained by loading at between 10,000 tive at the input end of a flash detonator. and 20,000 psi. For other lead azides — However, these explosives are much less such as PVA, colloidal, and RD1333 — load­ sensitive to heat pulses of short duration ing pressures are much higher. These are than is lead azide. given in Fig. 2—21. Lead styphnate is more sensitive than lead azide, however it cannot be used to Confinement of the explosives is an detonate tetryl, TNT, PETN, or RDX. Sil­ important factor in both the growth of det­ ver azide appears superior to lead azide in onation and the effective output resulting some respects, but it may never be avail­ from a stable detonation. In the early able in sufficient quantities. stages of detonation, the detonator case, closure, and the surrounding structure b. Base Charge. A secondary high ex­ should be considered as a container of high- plosive (par. 2— 10.1) is usually used as pressure gases. During these early stages, the base charge of a flash detonator. Both tightness — i. e., the absence of leaks — is tetryl and RDX have proven to be good the most important factor. As the growth base charges for flash detonators, and in of detonation progresses, the strength of most cases are the only explosives con­ the container becomes more important, sidered for this purpose. while the importance of leaks diminishes. As the detonation approaches its stable 2— 10.2.2.3 fU) General Design Considerations rate, the pressure exceeds the bursting strength of any practical container and con­ The total energy released by a flash det­ finement becomes a matter of inertia. In onator is the sum of the heat of detonation relatively thin-walled containers, the con­ and the quantity of the various explosives finement afforded by the inertia of the con­ used. Of this total energy, only the energy tainer is related to the weight ratio of the from the high-order detonation is the effec­ charge to case C/W .

2—32 AMCP 706-240

i.O - 30.000 40.000 30.000 25.000

20.000 TNT I 5 — TETRYL' " v 15.000 ■ PETN /■ ROX 10.000

2.0 iii a. (Azi LEAO STYPHNATE 3.000 (A UJ o 4.000 £ z o 3.000 O 2 5 LEAO AZIDE 2,500

2.000

— 1,500

3.0

- 1,000

A STRAIGHT LINE THROUGH THE POINT SHOWN FOR A PARTICULAR EXPLOSIVE WILL INTERSECT THE TWO SCALES TO SHOW THE LOADING DENSITY RESULTING FROM ANY GIVEN LOADING PRESSURE. - 300 EXAMPLE! THE DENSITY OF LEAD AZIDE PRESSED AT lOpOOpsi IS ABOUT 2.9

USE WITH CAUTION AT HIGH PRESSURES

FIGURE 2 — 2UU) — LOADING PRESSURE VERSUS DENSITY NOMOGRAPH

2— 10.2.3(11) D elay Elements Delay elements Eire classified as either Delay elements are incorporated into vented or obturated. Vented delays allow hand grenade fuzes to provide time for the the gases generated by the initiator and grenade to reach the target before det­ delay element to escape. Obturated delays onating. The most typical delay time re­ are inherently independent of the effects quired for fragmentation hand grenades is of ambient pressure and humidity. Obtura­ about 4.5 sec. tion also helps in the design of shorter de­ The delay element can be a mechanical lay times because the resulting rise in pres­ or electrical device, but simple and inex­ sure increases the burning rate. Further, pensive delay columns of explosive mate­ because the delay is protected from the rials are the ones used in current frag­ ambient atmosphere, more reliable and mentation hand grenades. Generally, these consistent delay times can be achieved. delay columns burn like a cigarette, i. e., For these reasons, modern U. S. fragmenta­ they are ignited at one end and burn lin­ tion hand grenades use obturated delays early. exclusively.

2—33 AMCP 706-240

2— 10.2.3.) IU} Delay Compositions TABLE 2-7(U). GASLESS DELAY COMPOSITIONS’ IN CURRENT USE ' Explosives for delay elements are classi­ fied as either gas-producing delay charges Fuel Oxid ant Inert or gasless delay charges. Each type is dis­ Boron Barium Chromic None cussed briefly in the paragraphs which fol­ Chromate Oxide 4 to 11 89 to 96 - low. 13 to 15 40 to 44 41 to 46 Manganese Bar ium Lead None Chromate Chromate 2— 10.2.3.2(U) Gas-producing Delay Charges 45 io 30 0 to 40 15 to 70 20 to 50 70 to 40 10 None Molybdenum Barium P o o s sium Black powder is the largest class of gas- Chromate Perchlorate producing delays. Black powder is easily 20 to 30 70 to 60 10 loaded and ignited. It is relatively inex­ Ni-Zr Barium Potassium None pensive and is available in a variety of Alloy Chromate Perchlorate 60 14 granulations. Black powder is affected by Ni-Zr Mix Barium Potassium None moisture and atmospheric pressure, but Chromate Perc hlorate 5/31 22 42 this is not a problem in the design of 5/17 70 8 obturated delay elements. However, black Seleni um Barium _ Talc powders do produce considerable quantities Peroxide 0.5 (added) 84 16 of gas, and an expansion chamber must Selenium BaO, — Tio/Iead Alloy be provided between the top of the delay 20 80 Powder (15/85) column and the primer (Fig. 2— 10). 20

Silicon Red Lead — Cel lie 20 80 max. 8 parts 2— 10.2.3.3 (U) Gasless Delay Charges by weighc Tungsten Bari um Potassium Diatomaceous Gasless delay mixtures are basically Chromat e Perchlorate Earth thermit-type mixtures of a metallic fuel 27 to 39 59 to 46 9.6 5 to 12 and an oxidizing agent. The term gasless 39 to 87 46 to 5 4.8 3 to 10 Zirconium Lead - None must not be taken literally; gasless delay Dioxide compositions do produce some gas, but 28 72 chiefly as the result of impurities. • Percentage by weight Table 2—7 lists gasless delay composi­ tions in current use. The ranges listed for the compositions allow for adjustment of IN P u T END burning rates over wide ranges.

2—10.2.4 (U) Rolays

A relay (Fig. 2—22) is a small explosive component that amplifies a relatively weak explosive impulse and applies it to the next Component in the explosive train. In most fragmentation grenades, the relay is usually the last charge increment in the delay column (Fig. 2—23). Nearly all relays are loaded with lead azide. The relay cups are almost always made from aluminum. Since a relay is -<------0 160 usually the last charge increment in a gre­ nade delay column, its diameter is deter­ O U T P U T END

mined by the diameter of the column. FIGURE 2 — 22(U) — TYPICAL RELAY 19

2—34 AMCP 706-240

2—10.2.5 (U) Main Charges

The purpose of the explosive train of a fragmentation hand grenade is achieved by the effective detonation of the main charge. The initiation of a main charge is not always a matter of simple "fire-mis­ fire” reliability. All main charge explosives are capable of a low-order detonation even though the probability of complete failure is low. Thus, the problem of main charge initiation is that of reliably initiating high- order detonation. The characteristics of various high ex­ plosives used for main charges are given earlier in par. 2— 10.1. Explosives consid­ erations involved in the design of frag­ mentation hand grenades are discussed in par. 2—6.2.

FIGURE 2 — 23IU) — RELAY USED AS LAST CHARCE INCREMENT IN A D ELA Y COLUMN 19

SECTION III (U)

CHEMICAL HAND GRENADES

2-11(U) GENERAL and their ability to ignite flammable mate­ rials must be minimized. Furthermore, an The three types of chemical grenades in irritant grenade must meet the environ­ general use are: (1) irritant grenades, mental requirements listed in par. 2—2. (2) incendiary grenades, and (3 ) smoke grenades. Irritant grenades are used al­ most exclusively for riot control. Occasion­ 2—12.2(U) AGENTS ally, they might be used to harass an 2-12.2.1 (U) Dispersal enemy. Incendiary grenades burn at a very high temperature and are used primarily Agents used in irritant grenades must be to destroy equipment. Smoke grenades are of a type that can be easily dispersed into used for screening or signaling. the air. The grenade should be designed so that the maximum concentration of agent per unit weight of grenade is generated and 2—12(U) IRRITANT GRENADES dispersed. To date, the two most effective methods of dispersing the agent are: 2— 12.1 (U) GENERAL REQUIREMENTS (1 ) the agent is mixed with combustible An irritant grenade must temporarily composition that is ignited when the gre­ incapacitate a rioter to prevent him from nade is thrown. The heat of combustion continuing his activity. Irritant grenades causes the agent to disperse into the air must be safe to handle and throw by troops by sublimation. The grenade casing re­ wearing gas masks; they must not flame, mains intact; the gases are dispersed spark, or explode when they are thrown, through small orifices in the casing.

2— 35 AMCP 706-240

(2 ) the agent, in micropulverized form, Generally, the agent and the fuel-oxidizer is dispersed instantaneously by the explo­ mixture are pressed to the desired shape, sion of a detonator. The explosion bursts which is usually cylindrical, and then coated the grenade casing, and the agent is dis­ with the starter mixture. However, in cases persed as a heavy concentration of small where the agent and the fuel-oxidizer mix­ particles. ture used tend to react with one smother, the two must be physically separated. This No matter which method is used, the dis­ can be accomplished by encapsulating the persed agent is nonpersistent, i.e., it is agent and embedding it in the fuel-oxidizer quickly dissipated by the wind. For a given mixture before pressing (Fig. 2— 26). amount of agent, the burning-type grenade has a longer dispersal time; dispersal times Tables 2—8, 2—9, and 2— 10 list the up to one minute are typical. However, the compositions generally used in buming- bursting-type produces a higher concentra­ type irritant grenades. Compositions for tion of the agent. Furthermore, the burst­ bur sting-type irritant grenades are given ing-type grenade cannot be kicked aside in Table 2-11. or picked up and thrown back at the thrower, which is possible with the burning- type if its dispersal period is too long. 2—I2.3(U) DESIGN CONSIDERATIONS

2—12.2.2(11) Typai of Agants 2— 12.3.1 |U) General

The three major types of agents used Irritant grenade compositions and in irritant grenades are: methods of dispersal are described in par. 2— 12.2. Considerations in designing (1 ) chloroacetophenone (C N ) the grenade itself, and in packaging the (2) diphenyl amine chloroarsine (D M ) composition are discussed in the p a ra ­ graphs which follow. (3 ) orthochlorobenzylidenemalo nitrile (CS) 2—12.3.2(li) Burning-type Irritont Grenode CN is a lachrymator, which causes eye irritation and tearing ("tear gas” ). It is Designing the canister, or casing, for a also an irritant to the upper respiratory burning-type irritant grenade is relatively tract. The effects of CN are relatively mild, simple. A canister constructed of thin rolled and wear off soon after exposure. steel is satisfactory. All present-day bum- ing-type irritant grenades use 28 gage DM is a stemutator, which causes vio­ steel. The dimensions of the canister must lent sneezing, intense headaches, nausea, be such that it can be easily held and and temporary debility. thrown. Past experience Indicates that a CS is a lachrymator that produces canister having a diameter between 2-1/2 severe burning sensations in the nose, and 3 in. and a length between 4 and 5 in. throat, and lungs. It is much more quick­ is satisfactory. Emission holes must be acting than both CN and DM. provided to allow the agent to disperse. These holes must be seeded to protect the Both CN and DM agents are sometimes fill from the effects of moisture. Adhesive used in the same grenade (par. 2— 12.3.2). tape, coated with lacquer, is satisfactory for this purpose. In addition to the agent, the filler or main charge of a burning-type irritant Fig. 2—24 shows a typical buming-type grenade requires a fuel-oxidizer mixture irritant grenade. The agent is dispersed and a starter mixture. The fuel provides through an emission hole in the bottom of the combustion necessary to disperse the the canister. The axial hole in the fill in­ agent. Oxygen for combustion is provided creases the burning surface of the compo­ by the oxidizer. The starter mixture ignites sition and provides venting. The area of the fuel-oxidizer mixture. the axial hole is a function of the mix

2-36 AMCP 706-240

TABLE 2-8(U). CN IRRITANT GRENADE COMPOSITION

AGENT/IGNITER CN Mixture * IGNITER COMPOSITION • PROPORTION

Chloroacetophenone 29 Potassium Nitrate 70.5 Igniter is poured into grenade as a slurry and then poured out in Diatomaceous Earth 5 Charcoal 29.5 the manner of a ceramic slip cast- Sucrose 17 mg. Approximately 5 grams (dry basis) is retained. Potassium Chlorate 24 Potassium Bicarbonate 25 Miit with: Press at: 5000-7500 lb Nitrocellulose 4 parts dead load Acetone 96 parts

* Parts by weight

TABLE 2-9(11). DM IRRITANT GRENADE COMPOSITION

AGENT/IGNITER DM Mixture • IGNITER COMPOSITION • PROPORTION

Diphenylamineehloroarsine 52.5 Potassium Nitrate 70.5 Igniter is poured into grenade in a slurry and poured out in the Potassium Chlorate 25.5 Charcoal 29-5 manner of a ceramic slip casting. Approximately 5 grams (dry basis) Sucrose 17 is retained.

Magnesium Oxide 5

Press at: 5000-7500 lb Mix with:

dead load Nitrocellulose 4 parts

Acetone 96 parts

•Parts by weight

TABLE 2-10(U). CS (ENCAPSULATED) IRRITANT GRENADE COMPOSITION

2 - 3 7 AMCP 706-240

TABLE 2-11(11). COMPOSITIONS FOR If the agent tends to react with the fuel- BURSTING-TYPE IRRITANT GRENADES oxidizer mix, the agent can be loaded into gelatin capsules which are then embedded MIXTURE % in the mix. Fig. 2—26 shows a CS irritant CS 95 grenade loaded in this manner.

Aerogel 5

DM 95 2—1 2.3.3 (U) Bursting-type Irritant Grenade Aerogel 5 The agent in the bursting-type grenade CN 92.0 i 0.5 is dispersed as a cloud of micropulverized Magnesium oxide 8.0 ± 0.5 particles. The casing of the grenade is made in two halves which are blown apart by the detonator. This releases the micro- being used and must be determined in each pulverized particles, essentially as an aero­ case. i sol, and the force of the detonation dis­ In some cases, a single grenade may be perses them. Since the principal purpose required to contain more than one type of of the detonator is to open the casing, no agent. If the agents are incompatible, they additional bursting charge is used. The must be kept physically separated within most uniform agent distribution is obtained the grenade. This can be accomplished by by using a special casing. The casing must loading the agents into separate containers be designed so that: (1) it readily breaks that are ignited simultaneously when the apart when the detonator explodes and grenade is fired. Fig. 2—25 shows a gre­ (2 ) it will not fragment when the grenade nade loaded with CN and DM agents which detonates. This last requirement is very tend to react with one another when in con­ important because irritant grenades are tact. used primarily for riot control, and the

2—38 AMCP 706-240

FIG U RE 2 — 25(U) — IRRITANT GRENADE LOADED WITH CH AND DM AGENTS probability of injuring a rioter must be enough to minimize the possibility of a kept to a minimum. Pig. 2—27 illustrates rioter picking up the grenade and tossing the most common method of meeting these it back. Time delays in the range of 1-1/2 requirements. A spherical plastic casing, to 3 sec meet this requirement. consisting of hemispherical sections, breaks in half at detonation. Since the casing Although the bursting-type irritant gre­ breaks up along the junction of the two nade uses a pyrotechnic time delay fuze sections, essentially no fragments are pro­ also, its fuze and explosive train differ from duced. those used in the burning-type grenade. A spherical casing does not readily lend it­ 2— 12.3.4(11) Foiing self to the use of a striker assembly or a safety lever of the types used with spheri­ Pyrotechnic time delay fuzes, because cal and barrel-shaped hand grenades. From of their low cost and acceptable perform­ a design and construction standpoint, a ance, are used in all present-day irritant plunger-type fuze (Fig. 2— 27) is more hand gTenades. Design considerations for adaptable to a spherical grenade. This type striker assembly and safety devices for a of fuze employs a spring-driven arm ing burning-type irritant grenade are the same sleeve which is held down by the thrower’s as those for the fragmentation hand gren­ thumb. The arming sleeve is released when ade, and are covered in pars. 2—9.2.1 the grenade is thrown, thereby allowing the and 2—9.2.2, respectively. The explosive arming pin to fly free. The spring then train for a burning-type irritant grenade is drives the detonator, which is contained in relatively simple, requiring only a percus­ the lower half sleeve, down onto the firing sion primer, a pyrotechnic delay column, pin to initiate grenade detonation. and a flash base charge. The delay column must be designed so that the delay is long The bursting charge of a bursting-type enough to protect the thrower, yet short grenade need only be great enough to

2-39 AMCP 706-240

FIGURE 2 — 2i(U) — IRRITANT GRENADE WlTHCS AGENT LOADED INTO GELATIN CAPSULES burst the casing and disseminate the agent. ploying a gasless delay composition, will A main explosive charge is not needed to greatly improve the storage characteristics burst the casing and disseminate the agent; of delay detonators. Reference 29 gives the explosive output of a detonator can be design details for a non vented-type delay used for this purpose. A delay-type detona­ detonator. tor — consisting of a primer, delay column, and the detonator explosive charges (Fig. 2—28) — is ideally suited to burst-type irritant grenades. Although vented delay 2— 13 (U) INCENDIARY GRENADES detonators have been used in the past, the 2— 13.1 (U) GENERAL use, or design, of a nonvented delay detona­ tor is desirable. Surveillance tests of M25 Incendiary hand grenades provide con­ irritant grenades with vented detonators centrated heat for destroying enemy equip­ uncovered a large quantity of duds, which ment or for destroying friendly equipment were believed to have been caused by per­ in danger of falling into enemy hands. An meation of the delay composition during incendiary hand grenade may also be used storage29. Nonvented delay detonators, em­ as a booby trapping device.

2—40 AMCP 706-240

ARMING SLEEVE

ARMING PIN

FIRING SPRING

UPPER HALF SLEEVE

GRENADE BODY FILLING M25AI

S l o w e r h a l f s l e e v e

FILLING PLUG SLIDER

FIRIN G PIN c l o s u r e p l u g

FIGURE 2 — 27(U) — TYPICAL BURST-TYPE IRRITANT GRENADE

sec at 4300°F3'. The thermate charge is capable of burning through a 1/4-in. thick steel plate.

2—13.3(U) DESIGN CONSIDERATIONS Except for the type of composition (par. 2— 13.2) and the manner in which the EXPLOSIVE composition is loaded, the design of an CHARGES incendiary grenade is the same as that for a burning-type irritant grenade. The same FIGURE 2 — 28(U) — DELAY-TYPE DETONATOR type of canister (par. 2— 12.3.2) and the same method of fuzing (par. 2— 12.3.4) are used in both grenades. However, while the 2—13.2[U) PYROTECHNIC COMPOSITION starter mixture is coated on the surfaces of an irritant grenade fill, it is pressed into A complete description of incendiary a separate cavity in the incendiary gre­ mixtures is given in Reference 30. In nade. Unlike the fill of an irritant grenade, present-day incendiary grenades, thermate the pyrotechnic fill of an incendiary gre­ is used as the pyrotechnic composition. nade, once ignited, will burn through until Besides starting fires, thermate, because the supply is depleted. of its high burning temperature, is capable of melting and/or distorting metals such as iron and steel. The thermate composi­ 2—14(U) SMOKE GRENADES tion used for present-day incendiary gre­ 2— 14.1 (U) GENERAL nades is listed in Table 2— 12. The M14 incendiary grenade (Fig. 2—29) contains Smoke hand grenades are used primarily 26 oz of thermate, and burns for about 40 for signaling and screening. White and

2— 41 AMCP 706-240

TABLE 2—12{U). INCENDIARY GRENADE COMPOSITION

THERMATE (THJ) INGREDIENT AND SPECIFICATION PARTS BY WEIGHT

Aluminum, Type 11, Mil-A-512, Grade D, Class 5 16 Aluminum, Type 11, Mil-A-512, Grade C, Class 4 9 Iron Oxide, MiI-I-275, Black, Class B 44

Barium Nitrate, MjI-B-162, Class 5 29 Sulfur, Mi -00487, Grade E 2

Castor oil (binder) not to exceed 0.2% by weight

STARTER MIXTURE * INGREDIENT PARTS BY WEIGHT

Red Lead 54.2 Manganese 34.2 Si l icon 11.6

Nitrocellulose ) „ . , , 8.0 k (binder) Acetone ; 92.00

• 25 grams of starter mixture are added to grenade

2— 42 AMCP 706-240 colored smokes are used for signaling, friendly forces providing artillery and air usually to identify friendly troops. For support. This support would normally not screening, white smoke is used exclusively. be provided within 40 to 50 yd of friendly troops, which is the maximum distance that a hand grenade can be thrown. 2— 14.2 (U) SMOKE COM POSITIONS For screening purposes, a smoke hand 2—14.2.1 (U) Dispersal grenade must produce a low-lying, dense smoke cloud instantly. Therefore, a burst­ All present-day smoke hand grenades ing-type grenade is required. used for signaling are of the burning type; depending upon the particular design, they 2—14.2.2 (U) Typai of Competition* disperse smoke for about 50 to 120 sec. There is no requirement for a bursting- Smoke compositions for green, red, yel­ type smoke hand grenade for signaling low, and violet smoke hand grenades are purposes. Bursting-type smoke munitions given in Table 2— 13. The composition for are used primarily as target indicators for white smoke is given In Table 2— 14.

TABL E 2-13(11). COLORED SMOKE HAND GRENADE COMPOSITIONS

SMOKE MIXTURE

PARTS BY WEIGHT INGREDIENT AND VIOLET RED YELLOW GREEN SPECIFICATION

42 40 14 4 Dye (MIL-D-3691) (MIL-D-37I8) (MIL-D-50029) (MIL-D-50029) Sodium Bicarbooate 24 25 33 22.6 O-S-00576 Potassium Chlorate 25 26 20 27 Mil-P-150, Grade B, Class 7

Sulfur. Mil-S-00487 9 9 8.5 10.4 Grade E

Benzanthrone, MiI-D-50074 — — 24.5 8

Dye, Solvent, Green Mil-D-3277 - - - 28 Press at 5000 — 5500 psi

IMPREGNATING MIXTURE INGREDIENT PARTS BY WEIGHT

Potassium Nitrate 152 Charcoal 65

Gum Arabic (dissolved in water 8:92) 9

STARTER MIXTURE INGREDIENTS PARTS BY WEIGHT

Potassium Nitrate 417 Silicon 309 Charcoal 46

Nitrocellulose 1 (binde0 13 Acetone j 317

2— 43 AMCP 706-240

TABLE 2-14(U). WHITE BURNING SMOKE (HC) COMPOSITION

Agent/l gniter Smoke Mixture e Starter Mixture e Proportion

He xachlofoe thane 4-1.53 Si licon 26

Zinc Oxide 46.47 Potassium Nitrate 35 25 grams of starter mixture are used Charcoal 4 Aluminum Powder _ _ _ Iron Oxide 22 (Amount required to obtain burning Aluminum Powder 13 lime) Nitrocellulose \ 6 > (binder) Acetone ) 94

• Pares by weight

Three parameters of a colored smoke grenade are given in Table 2— 17. The nor­ grenade that are of primary concern to the mal burning pressure for all of the gre­ designer are: (1) burning time, (2) burn­ nades is 1 psi. However, during tests, the ing temperature, and (3 ) burning pressure. orifices of the green and the violet grenade Tests on the M18 colored smoke hand gre­ sometimes became plugged, which caused nade32, which is the standard U. S. colored the internal pressure of these grenades to smoke grenade, indicate that these param­ rise to about 20 psi. The plugging resulted eters sometimes vary considerably for from thick liquid reaction products flowing different colors and even for any one through the orifices during combustion. particular color. The most noticeable differ­ When the internal pressure reached about ence among the grenades was in burning 20 psi, these reaction products were blown temperature (Table 2— 15). Red and yel­ through the orifices to distances up to 10 low grenades burn cooler than green and ft. The pressure then dropped to normal violet grenades. Furthermore, visual obser­ until the orifice became blocked again. vation indicates that green and violet gre­ Reference 32 gives methods for directly nades sometimes burn erratically, whereas measuring burning temperature, burning red and yellow grenades burn more uni­ pressure, and weight loss during burning. formly. Burning time can be calculated from either Average grenade burning times, and the pressure or weighbloss data. range of burning times for each color of The only standard bursting-type smoke smoke are given in Table 2— 16. Normal hand grenade in use contains 15 oz white burning pressures for each colored smoke phosphorous (WP). White phosphorous ignites on contact with the air and produces TABLE 2-V5(U). BURNING TEMPERATURE OF a dense white cloud when dispersed from a COLORED SMOKE HAND GRENADES32 grenade by a high explosive. Because WP ignites and bums on contact with the air, No. of Burning-Temperature Color Samples Range (°C) i WP grenades may also be used for incen­ diary and antipersonnel purposes. Green 4 580-750

Red 5 440-610 2^14.3(U) DESIGN CONSIDERATIONS Ycl low 4 420-510

Violet 5 630-780 2— 14.3.1 (U) Burning-type Smoke Grenades

1 The burning temper a turc variation for Design of the canister, or casing, for a individual grenades was abour 50°C- burning-type colored smoke grenade is the

2— 44 AMCP 706-240

TA8LE 2— 16(U). BURNING TIME OF COLORED SMOKE HAND GRENADES32

No. of Range of Burning Average Burning Color Samples Times {Sec) Time (Sec)

Green 7 45-57 52

Red 8 52-83 66

Yellow 8 5 1-60 55

Violei 7 47-71 59

TABLE 2-17(U). INTERNAL PRESSURE OF satisfactory casing material. Like burning- COLORED SMOKE HAND GRENADES32 type irritant grenades, burning-type colored smoke grenades require that the No. of Pressure Range During filler composition be drilled out and the Color Samples Normal Burning (psi) surface coated with the starter mixture to Green 4 0.05 - 1.0 provide sufficient burning surface and vent­ Red 6 0.04 - 0.41 ing. Y e 1 low 6 0.03 - 0.6 The standard U. S. colored smoke hand Violet 4 0.03 - 1.0 grenade, the M l8, is shown in Fig. 2—30. This grenade may be loaded with a red, green, yellow, or violet smoke composi­ same as that for the buming-type irritant tion. Burning times, and other data, for grenade (par. 2— 12.3.2). For present-day each of these compositions are given in applications, 28 gage steel has proven a par. 2— 14.2.2.

2—45 AMCP 706-240

The canister for the white smoke (H C ) Crimped joints do not provide adequate hand grenade is the same as that for the sealing for WP grenades. The top cover burning-type irritant grenade. However, for should be designed for a force fit. Particular the HC smoke composition, it is not neces­ care must be taken to design the fuze and sary to drill out the center of the filler. the fuze well so that no leakage can occur. Instead, the starter mixture can be loaded Fig. 2—32 shows the construction of into a separate cavity, as shown in older-type WP grenades. The most recent Fig. 2—31. type, shown in Fig. 2—33, employs a scored steel casing. A scored casing breaks up 2— 14.3.2(11) Bursfing-lypo Smoke (WP) Grenades more uniformly and more quickly, and re­ sults in a better dissemination of the WP White phosphorous ignites on contact filler. Furthermore, the resulting case frag­ with air. Therefore, the grenade must be ments enhance the antipersonnel effects of designed so that it is leakproof to prevent the grenade. air from entering the casing and filler from leaking out of it. Since leaks occur at joints, 2—14.3.3(U) Fuzing joints should be eliminated wherever possi­ Pyrotechnic time delay fuzes have ble. A "tin can” type of casing, such as proven satisfactory for use with both the that used for all present-day buming-type burning-type and the bursting-type smoke grenades, does not provide adequate seal­ grenade. Design considerations for fuzes ing for a WP grenade. Better sealing can used with buming-type smoke grenades be obtained by designing the casing so are the same as those for buming-type that its sides and bottom are of one piece irritant grenades (par. 2— 12.3.4). construction (Fig. 2—32). This avoids having to use a separate bottom cover and, The fuze and explosive train for a burst­ consequently, eliminates a major joint ing-type smoke (W P) grenade are the same through which leakage might occur. as for a fragmentation hand grenade, and

f i g u r e 2 — 3 U U ) — W h i t e S m o k e (H e ) grenad e

2—46 AMCP 706-240

FIGURE 2 — 32(U) — WP SMOKE HAND GRENADE

FIGURE 2 — 33(U)— WP SMOKE HAND GRENADE WITH SCORED FRAGMENTING CASING

2 - 4 7 AMCP 706-240 are covered in pars. 2—9.2.1 and 2—9.2.2, fragmentation grenade, a premature func­ respectively. The WP grenade requires a tion can cause serious injury to the thrower time delay of 4 to 5 sec because, like the or to friendly troops.

(U) REFERENCES

1. AMCP 706-179, Engineering Design 9. Gurney and Sarmousakis, The Mass Handbook, Explosives Series, Explo­ Distribution of Fragments from sive Trains. Bombs, Shells, and Grenades, Report No. 448, Ballistic Research Labora­ 2. TECP 700-700, Interim Pamphlet No. tories, Aberdeen Proving Ground, Md., 70-90, Arena Tests of High Explosive February 1944. Fragmentation Munitions, U.S. Army Test and Evaluation Command Mate­ 10. Solem, Shapero, and Singleton, Explo­ riel Test Procedure, 20 August 1963. sives Comparison for Fragmentation 3. T. E. Sterne, A Provisional Casualty Effectiveness, Report NAVORD 2933, Criterion, Technical Note No. 370, Naval Ordnance Laboratory, Aug­ Ballistic Research Laboratories, Aber­ ust 1953. deen Proving Ground, Md., March 1951. 11. J. E. Shaw, A Measurement of Drag Coefficient of High Velocity Frag­ 4. AMCP 706-245, Engineering Design ments, Report No. 744, Ballistic Re­ Handbook, Ammunition Series, Sec­ search Laboratories, Aberdeen Prov­ tion 2, Design for Terminal Effects ing Ground, Md. (CONFIDENTIAL). 12. D. J. Dunn and W. R. Porter, Air Drag 5. M. M. Hillyard, Fragmentation Char­ Measurements of Fragments, Memo acteristics of the Soviet Hand Grenade, Report No. 915, Ballistic Research Model RG-42, As Compared to the Laboratories, Aberdeen Proving U.S. M26 Hand Grenade. Memoran­ Ground, Md., A ugust 1955 (C O N F I­ dum Report No. 764, Ballistic Re­ DENTIAL). search Laboratories, Aberdeen Prov­ ing Groujid, Md., February 1954 13. R. W. Gurney, The Initial Velocities (CONFIDENTIAL) — AD 34752. of Fragments from Bombs, Shells, and Grenades, Report No. 405, Ballistic 6. A. R. Vincent and M. Pedicini, An Research Laboratories, Aberdeen Effectiveness Evaluation of the M-16 Proving Ground, Md., September 1943. Antipersonnel Mine, Memorandum Re­ port No. 835, Ballistic Research Lab­ 14. D. J. Dunn, A Fragmentation Study of oratories, Aberdeen Proving Ground, Hand Grenades, Memo Report No. Md., October 1964 (C O N F ID E N T IA L ) 558, Ballistic Research Laboratories, — AD 58898. Aberdeen Proving Ground, Md., July 1961 (CONFIDENTIAL). 7. Mott and Linfoot, AC 3642 (Great 15. D. J. Dunn and T. E. Sterne, Hand Britain). Grenades for Rapid Incapacitation, 8. Mott, Fragmentation of H. E. Shells, Report No. 806, Ballistic Research A Theoretical Formula for the Distri­ Laboratories, Aberdeen Proving bution of Weights of Fragments, AC Ground, Md., April 1952 — AD 87752, 3642 (Great Britain), March 1943. (CONFIDENTIAL).

2—48 AMCP 706-240

(U) REFERENCES (Cont'd)

16. AMCP 706-107, Engineering Design 24. AMCP 706-106, Engineering Design Handbook, Elements of Armament Handbook, Elements of Armament Engineering, Part Two, Ballistics. Engineering, Part One, Sources of Energy. 17. R. Schofield, Examination and Evalua­ 25. AMCP 706-177, Engineering Design tion of: (A ) Grenade, Hand, Offensive, Handbook, Explosives Series, Prop­ Type 54S, W/Fuze Type 54S and (B) erties of Explosives of Military Inter­ Detonator for Grenade, Hand, Offen­ est. sive, Type 54S, Swedish, Memo Report No. 107, Samuel Feltman Ammunition 26. AMCP 706-178, Engineering Design Laboratories, Picatinny Arsenal, Handbook, Explosives Series, Prop­ Dover, N. J. (CONFIDENTIAL) — AD erties of Explosives of Military In­ 366568. terest, Section 2 (CONFIDENTIAL). 27. A. J. Clear, Standard Laboratory Pro­ 18. B. Kroll, Malfunction Investigation of cedures for Determining Sensitivity, Prematures, Grenade, Hand, Frag­ Brisance, and Stability of Explosives, mentation, M26, MK2, and MK3 with Technical Report 3278, Picatinny Fuzes M 204A l and M206A1, Techni­ Arsenal, Dover, N.J., December 1965 cal Report 3199, Picatinny Arsenal, — AD 476513. Dover, N. J., October 1964 — AD 454058. 28. MIL-STD-320, Terminology, Dimen­ sions, and Materials of Explosive 19. AMCP 706-210, Engineering Design Components Used in Fuzes. Handbook, Ammunition Series, Fuzes, 29. R. Snook and E. Demberg, Develop­ General and Mechanical. ment of a Non-Vented Delay Detona­ 20. Ordnance Explosive Train Designers tor for the M25A2 Riot Hand Grenade, Handbook, Report NO LR 1111, U. S. Technical Memo. 1642, Picatinny Naval Ordnance Laboratory, April Arsenal, Dover, N. J., July 1965 — AD 1952 (CONFIDENTIAL). 468157. 30. AMCP 706-185, Engineering Design 21. F. Gaines, Arctic Winter Environmen­ Handbook, Military Pyrotechnics tal Test of Fuze, Grenade, Hand, Series, Military Pyrotechnics, Part TI012, Report No. OTA/TB5/1401/ One, Theory and Application. 528, Ordnance Test Activity, Yuma, Arizona, September 1959 (CONFI­ 31. FM 23-30 Grenades and Pyrotechnics. DENTIAL) — AD 312696. 32. G. Haynes, Burning Temperatures and 22. AMCP 706-214, Engineering Design Pressures of M l 8 Colored-Smoke Gre­ Handbook, Ammunition Series, Fuzes, nades, CRDL Special Publication 1-54, Proximity, Electrical, Part Four Edgewood Arsenal, Md., October 1965 (SECRET). — AD 474437. 23. AMCP 706-215, Engineering Design 33. AMCP 706-294, Engineering Design Handbook, Ammunition Series, Fuzes, Handbook, Surface-to-Air Missile Proximity, Electrical, Part Five Series, Part Four, Missile Armament (CONFIDENTIAL). (SECRET).

2— if) 1 2 -5 0 AMCP 706-240

CHAPTER 3 (U)

RIFLE GRENADES

3—1 (U) GENERAL enemy tanks and armored vehicles, al­ though it may also be used against other For the purposes of this handbook, a types of enemy vehicles and against enemy rifle grenade is a grenade that can be fired structures. The chemical smoke grenade is from a standard infantry rifle. This includes used for signaling and screening. There is grenades designed specifically for rifle fir­ no requirement for an antipersonnel ing (Fig. 3— 1) and grenades that can be (APEFtS) rifle grenade or for an irritant- fired from a rifle by use of a special gre­ type chemical grenade. However, both nade adapter (Fig. 3—2). Both types are antipersonnel-type and irritant-type hand launched by a special auxiliary propellent grenades can be adapted to firing from the charge that is loaded into the rifle. Gre­ M l rifle. Furthermore, some foreign nations nades fired from special grenade launchers, have developed antipersonnel rifle gre­ and self-propelled grenade-type projectiles nades. For example, the French T32XO are not covered. Furthermore, smoke and rifle grenade2 is an antipersonnel fragmen­ illuminating ground signal devices, which tation-type grenade designed specifically resemble rifle grenades very closely and for rifle firing. are often fired from rifle grenade launchers, are not covered. These devices, because of 3—3 (U) GENERAL REQUIREMENTS their use, are classified as pyrotechnic items 1 . The general requirements for a rifle gre­ nade are the same as those for a hand There is at present no requirement for grenade (par. 2—2). Specific requirements rifle grenades that can be launched from a for each type of rifle grenade are discussed standard infantryman's rifle M14; however, later in this chapter. some of these grenades are still in inven­ tory and can be fired from the M l rifle. The antitank rifle grenade has been re­ 3—4(U) TERMINAL EFFECTS placed by the 66 mm rocket launcher M72 The required terminal effects for a rifle and the antipersonnel rifle grenade by the grenade are strictly defined for the particu­ 40 mm grenade launcher M79 (see par. lar type of grenade. Terminal effects, such 1—4.2). Both of these new weapons are as the defeat of armor, smoke signals, superior to rifle grenades in range accuracy screening, etc., are discussed later in this and effectiveness. However, the informa­ chapter. Generally, however, the maximum tion given in this chapter is to preserve range of all rifle grenades is limited by technical knowledge on the subject, and to the recoil that the soldier and rifle can be prepared if a unique fighting situation withstand. If a grenade is fired with the again requires rifle grenades. rifle stock resting on the ground (Fig. 3—3), the stock may break if the recoil is too 3—2(U) TYPES OF RIFLE GRENADES great If the grenade is shoulder-fired (Fig. 3—3), excessive recoil may injure the firer. The two basic types of rifle grenades in These two factors limit the weight and, present use, due to an existing inventory, therefore, the payload, of a rifle grenade are the high explosive antitank (H EAT) and the maximum range that the grenade grenade and the chemical smoke grenade can be fired. Operational and test data adapted to firing from the M l rifle. The limit the maximum range of a 1-1 / 2-lb HEAT grenade is used primarily against grenade to about 200 yd. This results in a

3-1 AMCP 706-240

F ig u r e j —U u) — t y p ic a l r i f l e Gr en a d es AMCP 706-240

FRAGMENTATION HAND GRENADE. M26AJ

a r m in g clip

l o n g c l a w

SHORT CLAWS

RETAINER CUP

SAFETY LEVER

s t a b iliz e r ASSEMBLY

F N

FIGURE 3 — 20/) — HAND GRENADE ADAPTED FOR RIFLE FIRING recoil of about 75 ft-lb which can be with­ increase the range, can result in any one stood by both the firer and the rifle stock. or more of the following: Other factors besides the strength of a. Breakdown of the cartridge and fol­ the rifle stock and the ability of the firer to lower guide in the feed mechanism of the withstand the recoil limit the range of a rifle. rifle grenade fired by an auxiliary charge to about 200 yd. Attempts to increase the b. Breakdown of the rifle trigger mech­ size of the auxiliary charge, and thereby anism.

3 -3 AMCP 706-240

G REN AD E s i g h t o n o p p o s it e S id e o f s t o c k

DIRECT FIRE

SLING MAY BE MARKED TO SHOW ANGLE OF FIRE

HIGH ANGLE FIRE

F igure 3 — 3

c. Breakdown of the gas cylinder and The launcher is fitted over the rifle muzzle relief mechanism in the front part of the similar to the way that a bayonet is rifle. attached to a rifle. The launcher is de­ signed so that its bore is aligned with the d. Splitting of the rifle grenade stabil­ rifle’s bore. A rifle grenade is then slipped izer. over the launcher so that the tubular sec­ tion of the grenade stabilizer is locked in 3—5 (U) OPERATION AND ACCURACY place by a retainer spring on the launcher. Several operations must be performed If a hand grenade is to be rifle-launched, to fire a rifle grenade. First, the launcher an adapter must first be attached to the (Fig. 3— 4), and sometimes a special sight grenade, and the adapter slipped over the (Fig. 3—5), must be attached to the rifle. launcher. The auxiliary charge cartridge

CLIP RETAINER SPRING. MOUNTING SHOULDER

ANNULAR RINGS AND GROOVES FOR RANGE CONTROL

FIGURE 3 — 4(U) — RIFLE GRENADE LAUNCHER

3— 4 AMCP 706-240

before firing. Therefore, considerable train­ LEVELING SU ing is required to fire a rifle grenade with a high degree of accuracy.

3—6(U) HIGH EXPLOSIVE ANTITANK RIFLE GRENADE

3-—6.1 (U) GENERAL

The primary purpose of the HEAT rifle grenade is to defeat armored vehicles. It FRONT SIGHT POST may also be used to defeat other types of hard structures.

ELEVATIO N The three major factors that must be 5 CLICKS EQUAL 1 considered when designing a HEAT rifle grenade are: (1) the type of explosive FIGURE 3 — Sft/) — R IFLE GRENADE SIGHT charge used to defeat armor, (2 ) the methods of stabilizing the grenade in flight, is then loaded into the rifle and the rifle is and (3 ) the method of fuzing (including ready to fire. safety and arming). Each of these factors is discussed in the paragraphs which fol­ The required accuracy of a rifle grenade low. depends upon the type of grenade. Gener­ ally, the accuracy of a HEAT rifle grenade must be much higher than that of an 3—6.2(U) SHAPED CHARGES APERS or a chemical smoke rifle grenade. There are three basic methods — other The accuracy of an APERS rifle grenade than mines — of defeating armored vehicles. must, in turn, be greater than that of a These are: chemical smoke grenade. The primary rea­ son for this is that the penalty incurred for 1. Penetration of the armor by a inaccuracy is greatest for a HEAT grenade kinetic energy projectile. A kinetic energy and least for a smoke grenade. projectile is basically a solid steel projectile fired at a velocity high enough to provide Many variables enter into the accuracy the kinetic energy required for the projec­ of a rifle grenade, and some of these varia­ tile to penetrate the target. Typically, bles are not under the control of the gre­ velocities of 3000 to 5000 fps are required nade designer. For example, while the aero­ for this type of projectile. Since rifle gre­ dynamics of the grenade, the accuracy of nades achieve a velocity of only 150 fps, the launcher and sight calibrations, and they cannot be designed as a kinetic the reliability of the auxiliary charge are energy-type projectile. under the designer’s control; the firer’s skill at estimating the range of a target 2. Spalling of armor. This method is (under stress the range estimation* error used to defeat armor without actually pene­ a approximates 25% true range) and the trating it. By using a high explosive plastic speed of a moving target, and the manner (HEP) filler in a deformable casing, an ex­ in which the rifle is supported when the plosion in intimate contact with the outside grenade is fired, are not under the de­ of an armor plate can produce sufficient signer’s control. The greatest variable is shock to cause a spall on the inside surface the skill of the firer. Because of the short of the plate. This spall, which is roughly range of a rifle grenade, the rifle must be circular in shape, is projected at high velo­ fired at some angle above the horizontal city to cause serious damage within the after estimating the range to the target. armored vehicle. For proper performance, In the case of HEAT grenades, the firer HEP rounds must strike the target at a must also estimate the speed of the target higher velocity than can be achieved by

3 - 5 AMCP 706-240 rifle launching. Therefore, HEP rounds are hole in the steel block. The deepest pene­ not considered for use as rifle-launched tration will occur when the shaped charge weapons. is at a standoff of several cone diameters. 3. Penetration of the armor by a high- By lining the cavity with some material velocity jet (shaped charge). In this — e.g., copper — the depth of shaped method, a high-velocity jet of metal parti­ charge penetration can be increased. How­ cles penetrates the armor after the projec­ ever, when a liner is used, maximum pene­ tile strikes the target; the projectile itself tration occurs when the charge is detonated does not penetrate. Unlike armor-piercing a short distance from the block, rather than projectiles, a shaped charge projectile does in contact with it. This Is because of the not have to strike a target at high velocity behavior of the metal liner as the detona­ to be effective. In fact, it is relatively inde­ tion wave travels through the explosive. pendent of striking velocity. Therefore, it When the end of the explosive opposite the is ideally suited for use in antitank rifle liner is initiated, the detonation wave grenade applications. Shaped charges are passes over the metal liner, causing the discussed further in the paragraphs which liner to collapse upon itself (Fig. 3—7). follow. When the collapsing liner material reaches 3—6.2.1 (U) Shaped Charge Principles 3 the axis of the system, it divides into two parts. A small part forms an extremely A shaped charge is essentially a cylin­ high-velocity jet, and the other part forms drical explosive with a cavity at one end. A a slower, but more massive, slug (Fig. cylindrical explosive with a cavity at one 3—7(D )). The high-velocity jet is responsi­ end will inflict more damage on a given ble for the relatively deep penetration material than an equivalent cylindrical ex­ achieved by a shaped charge. The tip of plosive without a cavity (Fig. 3—6). The the jet attains a velocity of about 25,000 charge with the cavity, although it con­ fps, and the rear portions of the jet attain tains less explosive, produces a deeper velocities of nearly 5000 fps. This velocity difference within the jet is a result of the physical characteristics of most shaped charges. At the apex of the cone, the ratio of the explosive charge to the liner mass is relatively large. However, as the detona­ tion progresses down the liner, the mass of the liner increases while the amount of explosive available to move it decreases. The ratio goes to zero at the base of the liner because there is no explosive at the base. Therefore, the various portions of the liner reach the axis at progressively lower velocities and generate a jet having a velo­ city gradient along its length.

Because the jet impacts a target at such high velocities, an exceedingly high pres­ sure is generated. Typically, this pressure is about 4 x 106 psi. The high pressure causes both the jet and the target to de­ form hydrodynamically. The jet moves the (a ) (8) target material radially and flows with it (Fig. 3—8). Penetration continues in this F ig u re 3 — s (U) — penetrations pr o d u c ed bv EXPLOSIVE CHARGES WITH AND manner until the jet is used up or until the without c a v it ie s jet decreases to some critical value.

3 -6 AMCP 706-240

FIGURE 3 — 7(U) — COLLAPSE OF A SHAPED CHARGE CAVITY LINER

Fig. 3—9 shows a typical H EAT rifle grenade. It contains a high explosive (Com­ position B ) hollowed out in the form of an inverted cone. The cone is lined with cop­ per. Since a shaped charge must be initi­ ated along the axis in the direction towards the target, a point-impact, base-detonating (PIB D ) type of fuze must be used. Various types of PIBD fuzes are discussed in par. 2— 9. However, the fuzing method shown in Fig. 3—9 appears to be the one best suited to rifle grenades. A piezoelectric (Lucky) element in the nose of the grenade de­ forms upon impact with the target. The emf developed by the lucky element initi­ ates an electric detonator at the base of the grenade. The rotor rotates the detona­ tor into line only if the grenade achieves a predetermined acceleration.

3— 6.2.2(U| Shaped Charge Design

A detailed description of shaped charge design is given in Reference 4. In addition, there are a large number of reports on shaped charge design published by FIGURE 3 — 8(U) — HYDRODYNAMIC DEFORMA TION OF Picatinny Arsenal, Dover, N. J., and the j e t and t a r g e t 11 Ballistic Research Laboratories (BRL),

3 - 7 AMCP 706-240

3—6.2.2.1 (U) Charge Characleriflict The length of the grenade body, and hence of the charge, is usually limited by aerodynamic performance considerations and by grenade weight specifications. In general, the penetration and the hole vol­ ume obtained increase with increasing charge length. They reach a maximum when the charge length is 2 to 2-1/2 times the charge diameter for heavily confined charges, and when the charge length is about 4 times the charge diameter for lightly confined or unconfined charges. Existing shape charge designs usually have one of the shapes 9hown in Fig. 3— 10. Although all three designs can be made to perform satisfactorily, each has certain ad­ vantages. Design (A ) has the advantages of ease of manufacture, higher explosive loading, and blast effect (because of the larger amount of explosive). Designs (B ) and (C ) are sometimes necessitated by the requirements for aerodynamic configura­ tion and accuracy. Design (B ) is the type found most suitable for H EAT rifle gre­ nades. A longer jet of high velocity can be achieved by using wave forming techniques, i.e., by placing a block of high explosive with a lower detonating rate in the center of the main charge. By doing this, the detonating wave hits the sides of the liner sooner than it reaches the apex, thereby reducing the time required to collapse the entire liner and form the jet. At the pres­ enttime, however, wave forming techniques

FIGURE 3 — 9(U)— MAJOR COMPONENTS OF A HEAT RIFLE GRENAOE

Aberdeen Proving Ground, Md. General shaped charge design considerations relat­ ing to rifle grenades are discussed in the paragraphs which follow.

3— 8 AMCP 706-240

are not considered economically feasible range of standoff is adequate to achieve 90 for rifle grenades. percent of the penetration achieved at opti­ mum standoff. Generally, the effectiveness of the jet is proportional to the detonating rate of the 3— 6.3(U) STABILITY explosive. Since the detonating rate is pro­ portional to loading density, the explosive Accuracy is one of the most important should be cast as solid as practicable. requirements for a H EAT rifle grenade. For the grenade to be accurate, its proba­ 3—6.2.2.2 (U) Liner Characteristic! ble error or standard deviation must be small. For a number of grenades of the Liners of many different shapes have same type fired at the same elevation and been investigated. To date, however, the launcher position, the greater the drag on most effective and most consistent results any one grenade, the shorter will be its have been obtained with conical liners of range. Thus, for accuracy the drag must be appropriate apex angle and wail thickness. essentially constant for all grenades of the Practical restraints limit the liner apex same type. For the drag to remain constant, angle to between 40° and 60°. Wall thick­ the grenade must be stabilized so that it ness is generally about 0.04 in. always travels nose first. The depth of the cavity formed in the The two methods of stabilization are target is related to the density of the liner spin stabilization and fin stabilization. Al­ material, as part of a complex relationship though spin stabilization is desirable be­ with the liner length, type of explosive used, cause of its simplicity and ease of imple­ explosive configuration, explosive confine­ mentation, rifle grenades must be fin- ment, amount of explosive, standoff, etc. stabilized because of the way that they are Both copper and low-carbon steel have been launched. found satisfactory for rifle grenade liners. A detailed description of stability design Since copper is denser than steel, the jet for fin-stabilized projectiles is given in Ref­ will penetrate further into the target when a erence 5. General considerations with re­ copper liner is used. However, the cavity spect to rifle grenades are discussed in the diameter will be smaller when a copper paragraphs which follow. liner is used. Copper liners are more effec­ tive against armor, while steel liners are The stability of a grenade in flight is more effective against personnel because dependent upon the shape of the grenade, they produce fragments. Since a HEAT its center of gravity, and the location of the rifle grenade is designed exclusively to de­ center of pressure with respect to the cen­ feat tanks and armored vehicles, a copper ter of gravity. A favorable location of the liner should be used in the shaped charge. center of pressure for a rifle grenade can be achieved by mounting fins on the stabili­ 3—6.2.2.3 (U! Standoff zer tube (Fig. 3—9). If the fins are placed near the rear of the stabilizer tube and are The shaped charge must be initiated be­ large enough, the lift on the fins will result fore excessive crush-up of the grenade nose in the center of pressure of the normal force occurs. There is an optimum standoff at being behind the center of gravity, thereby which the shaped charge is most effective. ensuring static stability. Because the cen­ Standoff distance is determined by the ter of pressure is to the rear of the center length of the HEAT grenade ogive, the of gravity, the overturning moment is nega­ velocity of the grenade, and the fuze func­ tive; therefore, the overturning moment tion time. The optimum standoff for a coni­ becomes a righting moment and tends to cal liner is often four conical diameters or reduce yaw. greater. However, the actual standoff dis­ tance is usually limited to from one to three Increasing the size of the fins shifts both cone diameters by aerodynamic considera­ the center of gravity and the center of pres­ tions involved in ogive shape and size. This sure towards the rear of the grenade.

3 -9 AMCP 706-240

Hence, since the total length of the grenade This is a relatively short time for mechani­ is usually limited, there is a fin size that cal fuze action to occur. will maximize the distance from the center Mechanical methods and electrical of gravity to the center of pressure. For methods of transmitting information from adequate stability, this distance should be the nose to the rear of the grenade have at least. 10 percent of the total length of been investigated. Both types are discussed the gTenade. in the paragraphs which follow. The stability of a rifle grenade design can be predicted roughly by using the data 3—6.4.1 (U) Mechanical Fuzing Methods^ given in Reference 5. However, the stability Two basic mechanical fuzing methods of a grenade can be determined with rea­ have been investigated to transmit infor­ sonable assurance only by wind tunnel tests mation from the nose to the rear of a rifle and firing tests. grenade. One method employs a so-called "spit-back” or "flash-back” fuze. In this 3—6.4 (U) FUZING type of fuze, a small shaped charge explo­ sive in the nose of the grenade is initiated To be effective, a shaped charge must by a percussion primer upon impact with be initiated along the axis in the direction the target (Fig. 3—11). The shaped charge towards the target. Since the grenade fires a jet rearward through a passage pro­ strikes the target "nose on,” a point-impact, vided in the main charge into a base base-detonating (P1BD) fuze must be used. booster charge which initiates the main Furthermore, there is an optimum standoff charge. Since the velocity of a shaped distance at which detonation should occur charge jet is very high (par. 3— 6.2.1), the (par. 3—6.2.2.3), and, therefore, theshaped triggering action caused by nose impact is charge must be initiated before excessive transmitted very quickly to the rear of the crush-up of the grenade nose occurs. Typi­ grenade. cally, the nose should not collapse more than about 1/4 in. before initiation of the This method, although it results in a shaped charge. Therefore, although a rifle shaped charge initiation very quickly after grenade is considered a low velocity pro­ grenade impact, depends upon a clear path jectile, a fuze capable of initiating the from the shaped charge in the grenade shaped charge in a matter of microseconds nose to the booster in the rear. This condi­ is required. For example, a rifle grenade tion is not always satisfied because parts of travels about 150 fps. On the assumption the grenade, and particular parts of the that the nose is permitted to collapse 1/4 fuze, sometimes become misaligned or de­ in. before the shaped charge is initiated, formed upon grenade impact. Therefore, then the time available from nose impact this fuzing method is no longer considered to shaped charge initiation is 140 p sec. for use in HEAT rifle grenades.

f ig u r e 3 — >KU) — B asic Pr in c ip l e of s p i t -b a c k f u z e

3 - 1 0 AMCP 706-240

The second mechanical fuzing method ment deforms, thereby generating sufficient makes use of grenade deceleration upon electrical energy to fire the detonator. A impact with the target. A firing pin, which separate power source is not needed since is backed by a mass of high inertia, is the deformation of the piezoelectric element, mounted in the rear of the gTenade (Pig. itself, produces the required electrical 3— 12). The grenade decelerates when it energy. strikes the target, and the firing pin slides Since the energy developed by the piezo­ forward and fires the percussion primer. electric crystal is typically only a few hund­ This type of fuze is inherently slow- red ergs, detonators used in rifle grenades acting. Furthermore, the grenade must have must have a very high sensitivity. For this a very rigid nose section so that the nose reason, a film-bridge detonator is used in will not collapse before the shaped charge present-day rifle grenades. A detonator of is initiated. Because of these disadvantages, this type, using graphite as the bridge this method of fuzing is not used in present- material, can be designed with a sensitivity day rifle grenades. of less than 100 ergs. Design considera­ tions for film-bridge detonators are given in 3—6.4.2(U) Electrical Fuiing Methods Reference 6. Input requirements and other data for various types of film-bridge detona­ Various methods of electrical contact tors are given in Reference 7. When deter­ fuzing that appear applicable to HEAT rifle mining the input requirements for a detona­ grenades are discussed in the paragraphs tor, however, the designer should keep in which follow. Of the methods discussed, mind that grenade impact with a target will however, only piezoelectric-type fuzing has not always be "nose-on.” Rifle grenades been seriously considered and developed. often strike the target obliquely, and as the The piezoelectric-type PIB D fuze is pre­ angle of obliquity increases, the electrical ferred for HEAT grenades because it can energy developed by the piezoelectric ele­ provide a response rate within practical ment decreases. For example, a flat piezo­ grenade size, weight, and geometry. All of electric element that produces 300 ergs the Other methods have certain limitations upon nose-on impact may produce only 2 that make them inferior to piezoelectric or 3 ergs upon impact at a 60° angle of fuzes with respect to effectiveness, relia­ impact. By using a curve-shaped piezoelec­ bility, ease of manufacture, and cost. tric element, performance at oblique angles is improved (Fig. 3— 13). 3—6.4.2.1 (Uj Piezoelectric Fuzing Since a HEAT rifle grenade requires a A piezoelectric fuze consists basically of PIBD fuze, the piezoelectric element is a piezoelectric element connected in series mounted in the nose of the round and the with an electric detonator. When a rifle gre­ detonator in the rear (Fig. 3— 13). Piezo­ nade strikes a target, the piezoelectric ele­ electric elements of barium titanate have

SHAPED CHARGE

INERTIA-TYPE FIRING PIN

f ig u r e 3 — i2(o) — Basic p r in c ip l e o f in e r t ia -t y p e F uze

3— 11 AMCP 706-240

proven satisfactory for rifle grenades. Both strikes the target, the magnet is ejected sides of the element are silver-coated to very rapidly from within the coil, thereby form electrodes, and an electrical connec­ inducing a high voltage in the coil. This tion is brought out from each side. Usually, voltage could, in turn, be used to initiate one side is grounded, and the other side an electrical detonator. connected by an insulated wire to the de­ tonator. 3—6.4.2.3 (U) Proximity Fuzes

Care must be taken when installing the At first glance, certain types of proximity element so that it is not mounted under fuzes, — such as capacity fuzes9, magnetic stress. Since a barium titanate element fuzes10, and, perhaps, electrostatic fuzes10 possesses capacitance, any charge result­ — might appear feasible for use in rifle ing from mounting stress will be stored by grenades. All of these fuzes are capable of the element. Furthermore, stresses result­ initiating detonation within a few inches to ing from setback at the time the grenade is a few feet of a target. However, these fuzes, launched may cause a charge to be de­ in addition to being much more complex veloped and stored. A third factor, heat, — and expensive than a piezoelectric fuze, which can produce stresses in the element, have other operational limitations as dis­ — may also cause a charge to be stored. cussed in References 9 and 10. Therefore, To overcome this problem, a bleeder resis­ they have never been considered for use tor is normally connected across the barium in rifle grenade applications. titanate element to dissipate any charge that might accumulate as the result of 3—6.4.3(U( Safety and Arming stress. The value of the bleeder resistor Safety and arming considerations are must be high enough to ensure that most of discussed in par. 2—9.2.1. In that para­ the energy resulting from impact is deliv­ graph, it was stated that a mandatory re­ ered to the detonator. Typically, a resistor quirement for all fuzes is that they must of about 1 megohm is satisfactory. A de­ be detonator safe, but that the require­ tailed discussion of piezoelectric elements ment has been waived for hand grenades is given in Reference 8. because they experience no unique forces that may be used for arming. However, 3—6.4.2.2/U) Inertia Generalor^type Fuzing a HEAT rifle grenade, because it does experience unique forces when it is Inertia generator-type fuzing systems launched, must employ a fuze that is deton­ have been investigated for contact fuzing ator safe. A simple and reliable way of applications. This type of fuze consists achieving a detonator safe condition is to essentially of a magnet encircled by a coil use an out-of-line detonator (Fig. 3— 14). of many turns of fine wire. When a round In the safe position, unintentional initiation

3— 12 AMCP 706-240

thereby causing the fuze to arm. For exam­ ple, this might occur during aerial delivery should a parachute fail to open. (2 ) if the fuze is designed to arm upon experiencing setback only, the grenade will become fully armed at launch, or a brief instant thereafter, which is considered un­ safe by U.S. standards. The fuze must not become fully armed until the grenade has traveled a safe distance from the launcher; typically, about 10 to 20 yd. Various types of arming mechanisms are capable of providing this delay after launch. -DETONATOR For example, an inertial weight that moves (IN-LINE) SHAPED CHARGE at setback can allow a simple escapement timer to rotate the detonator into line. Or, a sequential events setback mechanism (setback leaves) which monitors accelera­ tion time during launch and an escapement timer — e.g., the T1022 series fuze — may be used. Methods of designing these mech­ anisms, and other applicable mechanisms, are described in References 11 and 12. No matter which type of mechanism is used, it (8 ) FUZE ARMED CONDITION should be reversible, i.e., if a round ex­ periences a very brief acceleration shorter f ig u r e 3 — u(u) —Sim p le Ou t -o f -l in e d eto n a to r than that specified for arming, the fuze should not remain in a partially armed of the detonator cannot initiate the booster, State. It should, by itself, revert to the and, subsequently, the main charge. The completely unarmed state. booster charge, and, consequently, the main charge, can be initiated only when 3—7 (U) CHEMICAL RIFLE GRENADES forces associated with grenade launching The only chemical rifle grenades in pres­ cause the detonator to rotate into line. ent use are smoke-type grenades. There is A rifle grenade experiences a fairly no requirement for a riot-type or incendiary- large, short-time acceleration at launch. type grenade designed specifically for rifle Typically, this acceleration ranges between firing. However, both of these types may 500 and 1000 g, depending upon the propel­ be fired from the M 1 rifle by use of a lent charge and the launcher setting. De­ special grenade adapter. vices operated by setback forces resulting The two basic types of smoke rifle gre­ from this acceleration can be used to arm nades are the streamer-type and the the fuze, i.e., to rotate the detonator into impact-type. A streamer-type smoke gre­ line. However, the fuze should not be de­ nade is designed to issue smoke from the signed so that it arms simply because the start of its trajectory until it reaches its grenade experiences a specified accelera­ maximum range, which is about 200 yd. tion. Instead, it should arm only when it Most impact-type smoke grenades are de­ experiences a specified acceleration over a signed to ignite and burn upon striking the specified period of time. There are two rea­ ground at the end of their trajectory. How­ sons for this, namely: ever, the white phosphorous white smoke (1 ) the setback forces resulting from bursts at impact and releases the smoke as grenade launching might be duplicated dur­ a cloud within a second or so after impact ing rough handling and transportation, (par. 3—7.2.2.2).

3— 13 AMCP 706-240

3—7.1[U) SMOKE COMPOSITIONS the same as those for a H EAT rifle gre­ nade, and are discussed in par. 3—6.3. In Smoke grenades must produce a smoke general, the requirements for a smoke rifle of distinct color that is recognizable from grenade, particularly one of the streamer- various positions in relation to the sun and type, are not as stringent as those for the under various daytime atmospheric con­ HEAT rifle grenade, particularly with re­ ditions. To be tactically useful, the grenade spect to accuracy. must bum for about 1 minute, and the smoke must be identifiable from a distance of one-half mile on a clear day. 3—7.2.2 |U) Fuzing Three colors of smoke, — red, green, and Methods of initiating streamer-type and yellow, — are generally considered for use impact-type smoke rifle grenades are dis­ in smoke rifle grenades. The compositions cussed in the paragraphs which follow. Both of these smokes are given in Table 3— 1 for the burning-type and the bursting-type im­ streamer-type grenades and in Table 2— 13 pact grenades are discussed. for impact-type grenades. The tables also give the composition of violet-colored smoke, 3—7.2 .2 .1 (U) S>raam«r-typ« Smoir® Grenada but this smoke, because its visibility char­ acteristics are poor at long distances, is A streamer-type smoke grenade, in a not used in any present-day grenade. sense, does not require a fuze, although the device used to initiate the smoke mix­ White smoke is also used in smoke gre­ ture can be referred to as a fuze. Actually, nades. This type of grenade uses white the propellant gases produced by the pro­ phosphorous as the agent. pellant cartridge are used to ignite the mixture. As shown in F\g. 3— 15, the pro­ 3—7.2(U) DESIGN CONSIDERATIONS pellant gases pass through a baffle to re­ 3—7.2.1 (U) Stability duce the force. The gases then pass through a hole in the "fuze” body and ignite a pel­ Aerodynamic considerations involved in let of ignition powder. The ignition powder, designing a stable smoke rifle grenade are in turn, ignites the smoke mixture. TABLE 3-l(U). STREAMER-TYPE SMOKE GRENADE COMPOSITIONS

SMOKE m MIXTURE Green Red Yellow V iolei

Dye 156 122 149 122 Potassium Chlorate 116 143 89 143 Sucrose 1 16 143 68 143 Poiassium Bicarbonate 20 Press at 3000 psi (min)

IMPREGNATING MIXTURE STARTER MIXTURE

Potassium Nitrate 152 Potassium Nitrate 417 Charcoal 65 Silicon 309

Gum Arabic 9 Charcoal 4 6 (dissolved in water 8 :9 2 ) B inder: Nirroce llulose 13 Acetone 317

* Parts by weight

3— 14 AMCP 706-240

FIGURE 3 — IS(U)— STREAMER-TYPE SMOKE GRENADE

3-15 AMCP 706-240

Since a streamer-type grenade actually making the pin or wire more difficult to re­ has no fuze, it requires no arming mecha­ move, as shown in Fig. 3— 17. nism. Safety is inherent because the forces The fuze, and safety and arming for a required for initiation, i. e., the propellant bursting-type impact grenade (WP) is gases, can only be present when the gre­ essentially the same as that for the burn­ nade is launched from the rifle. They can­ ing-type, except that it requires a detona­ not be duplicated in transportation and tor to open the casing and disperse the fil­ handling. ler. A detonator of the same size and type as an ordinary blasting cap has proven 3— 7.2 .2.2(U) Impact-type Smoke Grenade satisfactory for this purpose.

Inertia-type impact fuzes have proven 3—8 (U) PROPELLANT CHARGES satisfactory for impact-type smoke gre­ Rifle grenades are projected from a rifle nades. For a grenade that burns after im­ by special blank cartridges. The use of pact, thi9 type of fuze consists essentially service ammunition, such as ball or AP of a high-inertia firing pin, a creep spring ammunition, is ABSOLUTELY PROHIB­ and a simple safety device (Fig. 3— 16). ITED, since it will most likely detonate the When the grenade strikes the ground at grenade, killing the firer. In the past, the end of its trajectory, the firing pin, be­ attempts have been made to design gre­ cause of its inertia, is driven into a stab nades that can be fired by service ammuni­ primer. The primer, in turn, ignites the tion. This was done to eliminate the hazard smoke mixture. of inadvertently using service ammunition rather than special blank cartridges. Gre­ A creep spring must be placed between nades of this design contained a central the firing pin and the primer to prevent the hole that "caught” the bullet, and were firing pin from moving forward as the gre­ referred to as bullet "catchers.” For vari­ nade decelerates due to air resistance. ous reasons, such as the need for a very rugged grenade to withstand bullet impact As air resistance causes the grenade to and the difficulty of designing a reliable decelerate in flight, there is a tendency for and safe grenade, the design of bullet- the firing pin to move forward (creep). If catcher rifle grenades has been abandoned. this movement is not restrained, the dis­ tance between the firing pin and primer Some foreign rifle grenades are launched may be reduced to a point where the firing with special cartridges having frangible pin cannot acquire sufficient energy to bullets of wood or plastic. However, these initiate the primer. The simplest way to cartridges resemble ball ammunition, overcome firing pin creep is to place a making identification in the dark difficult. spring between the primer and the firing Thus, this increases the possibility, and the pin. Methods of determining creep forces, hazards, of launching a grenade with the and of designing a spring to resist them, wrong ammunition. are given in Reference 12. The use of special blank cartridges (Fig. 3— 18) to launch grenades from an Arming safety for this type of rifle gre­ infantryman’s rifle is a standard require­ nade can be provided simply by locking the ment for U. S. grenades. The cartridge firing pin with a device that is removed by charge is limited in size by the rifle cham­ hand just prior to launching the grenade. ber; the amount of the charge is governed A safety pin or wire that passes through by the weight of the grenade and the re­ the firing pin and locks it in place is gen­ coil that the firer and the rifle, itself, can erally used. This pin or wire can be at­ withstand. tached to a clip that is snapped off by hand just prior to launch, which simplifies re­ The 7.62 mm M64 cartridge is loaded moving the pin or wire (Fig. 3— 16). How­ with 40 grains of IMR 4895, or 37 grains ever, some additional safety is provided by of HPC 4, or 45 grains of WC 830-

3— 16 AMCP 706-240

OGIVE STARTER MIXTURE CHARGE CLOSING PLUG

SMOKE CHARGE

EMISSION HOLE

TAPE RETAINER SAFETY CLIP FUZE ASSEMBLY FIRING PIN SPRING------

FIRING PIN

STABILIZER TUBE

FIN ASSEMBLY

FIGURE 3 — I MU) — BURNING-TVPE IMPACT SMOKE GRENADE

3-17 AMCP 706-240

FIGURE 3 — 17( 1/ ; — BURSTING-TYPE IMPACT SMOKE GRENADE

3— 1 0 AMCP 706-240

(A) Cartridge, Cal. 7.62 rmi. Rifle Grenade, M64

? 49-

'I------'Ll ” 1 " ■ (B) Cartridge, Cal. .30, Rifle Grenade, M3

FIGURE 3 — I8(U) — CARTRIDGES FOR RIFLE GRENADES

In cases where very light grenades are to be launched, the charge may be in­ creased by adding an auxiliary charge con­ The cal. 30 M3 cartridge is loaded with tainer in the base of the round so that it 40 grains of 1MR 4895 and 5 grains of A-4 will be ignited by the blank cartridge when black powder. the rifle is fired.

(U) REFERENCES

1. TM 9-1370-200, Military Pyrotechnics. 7. Electrical Initiator Handbook, The Franklin Institute, Philadelphia, Pa., 2. V. Wittenbreder, Exploitation of A p ril 1960, 3rd Ed. (C O N F ID E N ­ French T32XO Rifle Grenade, Tech. T IA L ) AD 319980. Memo. 1679, October 1965, Picatinny Arsenal, Dover, N. J. (C O N F ID E N ­ 8. L. Dor emus, Piezoelectric Elements as T IA L ) AD 366355. High Power Electrical Energy Sources, Tech. Report No. 2562, Picatinny 3. J. Regan, J. Apgar, Effects of Shaped Arsenal, Dover, N. J., September Charges Against Monolithic and 1958. Spaced Targets, Memo. Report No. 9. AMCP 706-212, Engineering Design 1678, Ballistic Research Laboratories, Handbook, Ammunition Series, Fuzes, Aberdeen Proving Ground, Md., July Proximity, Electrical, Part Two 1965 (C O N F ID E N T IA L ) AD 367657. (SECRET). 4. AMCP 706-245, Engineering Design 10. AMCP 706-214, Engineering Design Handbook, Ammunition Series, Sec­ Handbook, Ammunition Series, Fuzes, tion 2, Design for Terminal Effects Proximity, Electrial, Part Four (CONFIDENTIAL). (SECRET). 5. AMCP 706-242, Engineering Design 11. AMCP 706-210, Engineering Design Handbook, Ammunition Series, Design Handbook, Ammunition Series, Fuzes, for Control of Projectile Flight Char­ General and Mechanical. acteristics. 12. AMCP 706-215, Engineering Design 6. AMCP 706-179, Engineering Design Handbook, Ammunition Series, Fuzes, Handbook, Explosives Series, Explo­ Proximity, Electrical, Part Five sive Trains. (CONFIDENTIAL).

3 - 1 9 / 3 - 2 0 AMCP 706-240

CHAPTER 4 (U)

TRAINING AND PRACTICE GRENADES

4—1 (U) GENERAL

Various types of grenades are required to train personnel in the handling and use of service grenades. These grenades must simulate service grenades as closely as possible. However, they must be safe for use by personnel undergoing training and by instructors conducting the training. The paragraphs which follow discuss de­ sign considerations for training grenades and practice grenades. A third typ > of gre­ nade, called a simulated grenade, is not covered. This type is used simply to simu­ late a grenade burst during battle maneu­ vers, and is classified as a pyrotechnic item’ . It more closely resembles a fire­ cracker rather than a grenade.

4—2(U) TRAINING GRENADES Only fragmentation-type hand grenades require a training counterpart. Unfilled service hand and rifle chemical grenades may be used for training with little or no hazard. Practice-type HEAT rifle grenades (par. 4—3) can also be used as training grenades. A training grenade must be inert, i. e., F ig u r e 4 — Uu) — Train in g Hand grenad e it must contain no explosives or pyrotech­ nic of any kind. Its primary purpose is to 4—3 (U) PRACTICE GRENADES give the trainee the same "feel” as its service counterpart. Therefore, it should Only fragmentation-type hand grenades conform as closely as possible to the size and HEAT-type rifle grenades require and weight of the service grenade, and practice counterparts. Unfilled service should possess the same types of arming hand and rifle chemical grenades may be features. It can be loaded with sand or used as practice grenades. Flirthermore, similar material to simulate the weight of service chemical grenades, themselves, ex­ the explosive charge. Since the grenade cept for those containing white phospho­ must be handled and thrown over and over, rous, can be used for practice with little it must be as durable as practicable. hazard. A typical training grenade is shown in 4—3.1 (U) PRACTICE HAND GRENADE Fig. 4— 1. It can be compared with its serv­ ice counterpart, the MK2, which is shown A practice hand grenade differs from a in Fig. 2—6. training hand grenade primarily in that it

4-1 AMCP 706-240 contains a small explosive charge to simu­ Mk2 fragmentation gTenade shown in Fig. late detonation. Safety is the primary con­ 2—6. It consists of a cast iron Mk2-type sideration in designing the practice gre­ grenade body fitted with the standard fuze nade. A major requirement is that the ex­ for the Mk2 grenade. However, in place of plosive charge must not be great enough a detonator, a black powder igniter in a to break the gTenade casing. This elimi­ gilded metal case is used. A small charge nates the danger of trainees being struck of black powder in a cloth bag supplements by fragments. the igniter charge. A loading hole in the base of the casing allows the grenade to For simplicity and cost, practice gre­ be reloaded with explosive charge. nades generally use black powder as the explosive charge. Black powder produces a reasonable amount of white smoke and a fairly loud report. By confining the powder, and by adding about 10 percent of flaked aluminum to the charge, the brisance of the explosion, and, therefore, 4—3.2 (U) PRACTICE RIFLE GRENADE the loudness and sharpness of the report, A practice rifle grenade provides prac­ can be greatly increased. tice in handling and firing a particular type For economy, practice grenades should of service rifle grenade. A practice rifle be designed for reloading and reuse. To grenade does not contain any explosive accomplish this, the grenade body must be charges; therefore, it can also be used as rugged enough to withstand not only re­ a training grenade. peated impacts but also the repeated ex­ Rifle grenades are subject to a great plosions of the practice charge. Ideally, the deal of abuse, and therefore must be ex­ grenade should be designed so only a re­ ceptionally rugged if they are to be used placement explosive cartridge need be in­ repeatedly. The stabilizer assembly of a serted after each use. practice rifle grenade is particularly prone A typical practice grenade is shown in to damage by repeated firings. Therefore, Fig. 4—2. Its service counterpart is the it is desirable to design a practice grenade

STRIKER SPRING PRIMER

FUZE M205A1 STRIKER

DELAY ELEMEATT

BLACK POWDER IGNITER SAFETY LEVER JJI BLACK POWDER CHARGE JJ

CAST (RON BODY STOPPER

FIGURE 4 — 2 (U) — PRACTICE HAND GRENADE

4—2 AMCP 706-240

so that the assembly is replaceable. Re­ placement procedures should be simple enough to be carried out in the field with­ out the use of special tools. For example, the fins of the T44 Practice Rifle Grenade can be removed simply by rotating them 90 degrees, by hand. Replacement fins can be installed by slipping them onto the sta­ bilizer tubing and twisting them 90 de­ grees, by hand, to lock them in place 2. Fig. 4—3 shows a typical practice rifle grenade. It conforms to its service-type counterpart in shape, weight, and ballistic characteristics. The body is made of cast iron, and the stabilizer assembly is replace­ able. Practice rifle grenades can also be made with solid rubber bodies. These can be used against operational vehicles, with little risk of damaging the vehicles. However, it is usually more difficult to manufacture rub­ ber-type grenades to match the character­ istics of their service-type counterparts.

FIGURE 4 — 3(U) — PRACTICE RIFLE GRENADE

(U) REFERENCES

1. TM 9-1370-200, Military Pyrotechnics. 2. W. Cole, Production Engineering Study of T44 Rifle Grenade, Tech. Memo. 1468, Picatinny Arsenal, Dover, N. J., April 1965, AD 460580.

4—3 /4 —A AMCP 706-240

INDEX (U)

Page

Burning-type grenades impact smoke rifle grenade.... 3-13, 3-16 Acceleration, rifle grenade...... 3-13 irritant hand grenade...... 2-36, 2-38 Accuracy of hand grenades .. 2-3, 2-12, 2-13 Bursting-type grenade see also Throwing distance bursting charge...... 2-39 Adapters, grenade...... 1-2, 3-3 smoke hand grenade...... 2-46 see also Launchers smoke rifle grenade...... 3-13, 3-16 Agents bursting-type irritant grenade...... 2-38 loading into gelatin capsules...... 2-38 C types used in irritant grenades...... 2-36 Angle over which fragments Cartridges are projected...... 2-12 auxiliary charge...... 3-3, 3-5 blank...... 3-16 Antipersonnel rifle grenade...... 3-1 M 406...... 1-4 Arming M407 ...... 1-5 P1BD fuzes...... 3-10 Casing requirements ...... 2-20 optimum sh ape...... 2-14 safety o f ...... 2-20, 3-16 notched...... 2-15 Armor penetration...... 3-5 Casing radius...... 2-12 Armor spalling...... 3-5 Cause of premature function in Armored vehicles, methods of hand grenade...... 2-22 defeating...... 3-5 Cavity liner...... 3-6, 3-9 Auxiliary charge cartridge...... 3-3, 3-4 Charge Auxiliary charge container...... 3-19 b a s e ...... 2-32 bursting-type grenade...... 2-39 B m ain...... 2-35 prim ary...... 2-32 Barium titanate element...... 3-12 shapes...... 3-8 Barrel-shaped grenade...... 2-14 Charge container, auxiliary...... 3-19 Base charge...... 2-32 Charge-to-weight ratio...... 2-9, 2-12 Batteries, therm al...... 2-25 Chemical grenade compositions Black powder bursting-type irritant grenade...... 2-38 as gas-producing delay charge...... 2-34 CN irritant grenade...... 2-37 in practice grenades...... 4-2 colored smoke grenade...... 2-43 CS (encapsulated) irritant Blank cartridges...... 3-16 grenade...... 2-37 Bleeder resistor...... 3-12 DM irritant grenade...... 2-37 incendiary grenade...... 2-42 Booby trapping...... 1-2, 2-40 streamer-type smoke...... 3-14 Bullet catchers...... 3-16 white sm oke...... 2-44

l - l AMCP 706-240

INDEX(U) (Cont'd) Page Page Chemical hand grenades Energy, total...... 2-32 incendiary...... 2-40 Explosive trains...... 2-26 irritant...... 2-35 components...... 2-27 smoke...... 2-41 elements ...... 2-27 Chemical rifle grenades incendiary...... 3-13 Explosives smoke, see Smoke rifle grenades characteristics...... 2-28 classification...... 2-27 Chipping of fragments...... 2-17 compatibility with m etals...... 2-29 Colored smoke hand grenades cylindrical...... 3-6 burning temperature...... 2-44 for delay elements...... 2-34 burning time...... 2-45 plastic (H E P )...... 3-5 internal pressure...... 2-45 prim ary...... 2-27 secondary ...... 2-27 Controlled fragmentation...... 2-15 Cylindrical explosives...... 3-6

D F Definition of a grenade...... 1-1 Film-bridge detonator...... 3-11 Deformation, hydrodynamic...... 3-6 Firing p in ...... 2-21 Delay charges Forces, setback...... 3-13 gas-producing ...... 2-34 Fragmentation gasless...... 2-34 control...... 2-15, 2-16 Delay elements ...... 2-33 efficiency...... 2-7 tactical limitations o f...... 2-19 pattern...... 2-5, 2-18 Delay mixtures...... 2-34 FYagments, breaking and chipping o f...... 2-17 Detonation, growth in ...... 2-32 Fuze volum e...... 2-17 Detonator safe requirements Fuzing, fragmentation hand grenades for hand grenades...... 2-20 for HEAT rifle grenades...... 3-12 impact fuzes...... 2-22 proximity fuzes...... 2-19 Detonators pyrotechnic time d e la y ...... 2-19 black powder igniter...... 4-2 specification requirements...... 2-4 bursting-type grenade...... 2-39 delay-type ...... 2-41 Ftizing, irritant hand grenades...... 2-39 electric...... 2-26 Fuzing, rifle grenades explosives fo r...... 2-32 capacity fuze...... 3-12 film bridge...... 3-11 electrical fuzing...... 3-11 fla sh ...... 2-31 flash-back fuze...... 3-10 out-of-line...... 3-12 inertia generator-type fuze...... 3-12 smoke rifle grenades...... 3-16 inertia-type impact fuze...... 3-16 Diameter of hand grenade...... 2-12 magnetic fuze...... 3-12 mechanical fuzing...... 3-10 E piezo electric-type fuze...... 3-11 point impact base detonating Early development...... 1-2 (P I B D )...... 3-10 Effectiveness of fragmentation proximity fuze...... 3-12 hand grenades...... 2-17 spit-back fuze...... 3-10 1-2 AM CP 706-240

INDEX (U) (Cont'd) Page Page Fuzing, smoke hand grenades...... 2-46 Liner, cavity...... 3-6, 3-9 Loading pressure versus density...... 2-33 G Losses, closing c a p ...... 2-17 Gasless delay compositions...... 2-34 Gloves, effect on throwing M accuracy ...... 2-12 Maximum dimensions of Grenade adapters...... 1-2, 3-1 hand grenades...... 2-3 see also Launchers Maximum range, rifle grenade...... 3-1 Grenade launcher, M 79 ...... 3-1 Methods of firing grenades Grenade payloads...... 1-1 from rifles...... 3-4 Guerrilla-type w ars...... 1-2 Methods of projection...... 1-2 Gurney constant...... 2-9 MK2 grenade...... 4-1 M l rifle...... 3-1 H M14 incendiary grenade...... 2-41 High explosive plastic (H E P )...... 3-5 M16 rifle...... 1-4 High-velocity je t ...... 3-6 M18 colored smoke hand grenade...... 2-45 Hydrodynamic deformation...... 3-6 M25 irritant grenade...... 2-40 I M26 fragmentation Igniter, black powder...... 4-2 hand grenade...... 2-21, 2-22 Ignition powder...... 3-14 M72 rocket launcher...... 3-1 Inertia-type fuze, basic principle...... 3-11 M79 launcher...... 1-3, 3-1 Irritant hand grenades M217 electric fuze .... 2-22, 2-23, 2-24, 2-26 agents...... 2-35 M406 cartridge...... 1-4 burning time...... 2-36 design considerations...... 2-36 M407 cartridge...... 1-5 use o f ...... 2-35, 2-38 P K Packing...... 2-17 Kinetic energy projectile...... 3-5 Payloads...... 1-1

L Penetration, arm or...... 3-6 Launchers Physical size of hand grenades...... 2-12 M72 rocket...... 3-1 Piezoelectric-type fuze...... 3-12 M79 grenade...... 1-2, 3-1 XM 148...... 1-4 Potential energy...... 2-22 see also Adapters Powder, ignition...... 3-14 Lead azide...... 2-32 Practice hand grenades...... 4-1 Lead styphnate...... 2-32 Practice rifle grenade...... 4-2 Limits, rifle grenade inherent...... 3-1 Premature function, cause o f...... 2-22

l— 3 AM CP 706-240 UNCLASSIFIED

INDEX (U) (Cont'd)

Page Page Primary charge ...... 2-32 Shaped charge rifle grenade Primers description...... 3-5 composition...... 2-31 design characteristics...... 3-8 cup construction...... 2-30 principles o f...... 3-6 definition o f ...... 2-27 stabilization requirements...... 3-9 percussion...... 2-22, 2-30 Sight, rifle grenade...... 3-4 Probability Simulated grenade...... 4-1 of incapacitation ...... 2-14, 2-17, 2-18 Size, weight, and shape of hand Prohibited use of ball or grenades...... 2-3 AP service ammunition...... 3-16 Smoke hand grenades Projectile, kinetic energy...... 3-5 burning temperatures ...... 2-44 Propellant charges...... 3-16 burning times ...... 2-45 design considerations...... 2-44 Pull ring ...... 2-20 smoke compositions...... 2-43, 2-44 use o f...... 2-35, 2-43

R Smoke rifle grenades composition o f...... 3-14 Range, rifle grenade...... 3-1 design considerations...... 3-14 Recoil, rifle...... 3-1, 3-16 fuzing methods...... 3-14 impact types...... 3-13, 3-16 Relative effectiveness...... 2-17 stabilization requirements...... 3-14 R elays...... 2-34 streamer ty p e...... 3-15 Reloading practice grenades...... 4-2 Soviet RG-42 hand grenade...... 2-12 Resistor, bleeder...... 3-12 Spalling, arm or...... 3-5 Rifle grenade Spatial distribution...... 2-2 antipersonnel...... 3-1 Specifications, test...... 2-2 launcher...... 3-4 sight...... 3-4 Spit-back fuze, basic principles...... 3-10 Rifle, M l ...... 3-1 Stabilization, rifle grenades effects on accuracy...... 3-9, 3-14 Rifle, M 16...... 1-4 removable fins, practice Rifle recoil...... 3-1, 3-16 rifle grenade...... 4-2 shaped charge rifle grenades...... 3-9 Rocket launcher, M 72...... 3-1 smoke rifle grenades...... 3-14 Standoff, conical lin er...... 3-9 S Streamer-type smoke rifle grenades Safety see Smoke rifle grenades hand grenade requirements...... 2-20 Striker assem bly...... 2-21 impact type rifle smoke grenade.....3-16 lever and pull rin g...... 2-21 Switches typical requirements...... 2-3 fusible-link ...... 2-25 impact...... 2-24 Setback forces...... 3-13 spring-loaded...... 2-26 Shape of hand therm al...... 2-24 grenades...... 2-12, 2-14, 2-18 trembler-type...... 2-25 1— 4 UNCLASSIFIED UNCLASSIFIE§6^1«MWWf AMCP 706-240

INDEX(U) (Cord'd) Page

T Terminal effects of rifle grenades...... 3-1 Weight, size, and shape of hand grenade...... 2-3 Throwing distance...... 2-12, 2-43 White phosphorous smoke hand Training grenades...... 4-1, 4-2 grenade...... 2-47 T32XO rifle grenade...... 3-1 White smoke (H C ) hand grenade...... 2-46 T44 practice rifle grenade...... 4-3 Wound ballistics...... 2-3, 2-4, 2-17 V X Velocity XM148 launcher...... 1-4 initial...... 2-9 of fragments...... 2-12 of rifle grenades...... 3-5 striking ...... 2-9

U. S. COVERJfMENT PRINTING O F F IC E : 1968 O -2 3 3 -6 3 1 CONFIDENTIAL I—5/1—6 UNCLASSIFIED UNCLASSIFIED ENGINEERING DESIGN HANOBOOK SERIES Listed below are the Handbooks which have been published or are currently being printed. Handbooks with publication dates prior to 1 August 1962 were published as 20-series Ordnance Corps pamphlets. AMC C ircular 310-38, 19 Ju ly 1963, redesignated those publications as 706-series AMC pamphlets ( i . e . , OftOP 20-138 was redesignated AMCP 706-138). A ll new, reprinted, or revised Handbooks are being published as 706-series AMC pamphlets.

Genera ’ i>:ri Viz?.- I turccna Subjects Ballistic Missile Series (continued) No. T itle No, Ti tie 106 Elements of Armament Engineering, Part One, 283 Aerodynamics Sources of Energy 284(C) Trajectories (U) 107 Elements of Armament Engineering, Part Two, 286 Structures B a llis tic s 108 Elements of Armament Engineering, Part Three, Ballistics Series Weapon Systems and Components 110 Experimental Statistics, Section 1, Basic Con­ 140 Trajectories. Differential Effects, and Data cepts and Analysis of Measurement Data for Projecti les 150 Interior Ballistics of Guns 111 Experimental Statistics, Section 2, Analysis of Enumerative and Class)ficatory Oata 160(S) Elements of Terminal B a llis t ic s , Part One, Introduction, K ill Mechanisms, and 112 Experimental Statistics, Section 3, Planning and Analysis of Comparative Experiments Vulnerability (U) 161(S) Elements of Terminal B a llis t ic s , Part Two, 113 Experimental Statistics, Section 4, Special Collection and Analysis of Data Concerning Topics Targets (U) 114 Experimental Statistics, Section 5, Tables 121 Packaging and Pack Engineering )62(S-RD) Elements of Terminal B a llis t ic s , Part Three, 134 M aintainability Guide for Oesign Application to M issile and Space Targets (U) 135 Inventions, Patents, and Related Matters (Revi sed) Carriages and Mounts Series 136 Servomechanisms, Section 1, Theory 340 Carriages and Mounts--General 137 Servomechanisms, Section 2, Measurement and 341 Cradles Signal Converters 342 Recoil Systems 138 Servomechanisms, Section 3, Amplification 343 Top Carriages 139 Servomechanisms, Section 4, Power Elements 344 Bottom Carriages and System Design 345 Equf 1 ibrators 170(C) Armor and Its Application to Vehicles (LI) 346 Elevating Mechanisms 255 Spcclrol Chotocieristi cs of M unle Flash 347 Traversing Mechanisms 270 Propellant Actuated Devices 270(C) WarheadS'-Certeral (tl) Guns Series 331 Carr pensoting Elemenrs (Fite Control Series) 260 Guns--Genera 1 Ammunit i on and explosives 5ers.es 252 Gun Tubes 175 Solid Propellants, Part One 176(C) Solid Propellants, Part Two (U) Military Pyrotechnics Series 177 Properties of Explosives of Military Interest, Section 1 185 Pan One, Theory and Application 178(C) Properties of Explosives of Military Interest, 186 Pan Two, Safety, Procedures and Glossary Section 2 (U) 187 Part Three, Properties of Materials Used In Pyrotechnic Compositions 179 Explosive Trains 139 Port Five, Bibliography 210 Fuzes, Genera) and Mechanical Surface-to-Air Missile Scries 211(C) Fuzes, Proximity, E le c tr ic a l, Part One (U) 212(5) Fuzes, Proximity, E le c tr ic a l, Part Two (U) 291 Part One, System Integration 2I3(S) Fuzes, Proxim ity, E le c tr ic a l, Part Three (U) 292 Part Two, Weapon Control 214(5) Fuzes, Proximity, E le c tr ic a l, Part Four (U) 293 Part Three. Computers 215(C) Fuzes, Proximity, E le c tr ic a l, Part Five (U) 294($) Part Four, M issile Armament (U) 240(D) Grenodes 295(5) Part Five, Countermeasures (LI) 242 Oesign for Control of P ro je c tile Flight 2% Part Six, Structures and Power Sources Charac teri s ti cs 297(S) Part Seven, Sample Problem (U) 244 Section 1, A r tille r y Ammunition--GeneraI, with Table of Contents, Glossary and Materials Series* Index for Series 149 Rubber and Rubber-Like Materials 245(C) Section 2, Design for Terminal Effects (U) 212 Gasket Materials (Nonmetal 1ic) 246 Section 3, Design for Control Of Flight 691 Adhesives Charac ten s ti CS (out of print) 692 Guide to Selection of Rubber 0-Rings 247 Section 4, Oesign for Projection 693 Magnesium and Magnesium Alloys 248 Section 5, Inspection Aspects of A rtille ry 694 Aluminum and Aluminum Alloys Ammunilion Design 697 Titanium and Titanium Alloys 249 Section 6, Manufacture of M etallic Components 698 Copper and Copper Alloys of A r tille r y Ammunition 699 Guide to Specifications for Flexible Rubber Automotive ikrzer, Products 355 The Automotive Assembly 700 Plastics 356 Automotive Suspensions 721 Corrosion and Corrosion Protection of Metals 722 Glass Ballistic Missile Scries 281(S-R0) Weapon System Effectiveness (U) 282 Propulsion and Propellants ‘ The Materials Series is being published as M ilita ry Handbooks (MIL-HDBK-) which are available to Department of Defense Agencies from the Naval Supply Depot, 5801 Tabor Avenue, Philadelphia, Pennsylvania 19120.

UNCLASSIFIED