lAHI FM 7-15 Copy 3 WAR DEPARTMENT INFANTRY FIELD MANUAL HEAVY WEAPONS COMPANY, RIFLE REGIMENT May 19, 1942 CHANNON, R.I. FM 7-15 INFANTRY FIELD MANUAL HEAVY WEAPONS COMPANY, RIFLE REGIMENT UNITED STATES GOVERNMENT PRINTING OFFICE WASHINGTON : 1942 WAR DEPARTMENT, WASHINGTON, May 19, 1942. FM 7-15, Infantry Field Manual, Heavy Weapons Company, Rifle Regiment, is published for the information and guidance of all concerned. [A. G. 062.11 (4-18-42).] BY ORDER OF THE SECRETARY OF WAR: G. C. MARSHALL, Chief of Staff. OFFICIAL: J. A. ULIO, Major GeneraZ, The Adjutant General. DISTRIBUTION: D7 (2); R 7 (3); Bn7 (5);IC7 (20). (For explanation of symbols see FM 21-6.) Ix TABLE OF CONTENTS CHAPnr 1. General. Paragraphs Page SECTION I. Composition, a r m a me n t, and equipment .-. ...............1-6 1 1I. Tactical employment of heavy weapons company .------------7-18 7 CnAPTER 2. Marches and bivouac _____ .- ....... 19-24 19 Cnzrm 93. Offensive combat. SECTION I. General .-. ..................25 26 II. Approach march _-------.------ 26-29 30 III. Reconnaissance prior to attack, and orders . .-........... 30-33 38 IV. Attack ------------------------- 34-44 44 - V. Night attack .-----------------45-47 52 VI. Raids .-------------------------48 56 VII. Attack in woods -.-. ...........49 51 56 VIII. Attack of towns and villages --- - 52 59 IX. Attack of river line ___________ 53-55 60 CHATERe 4. Defense and retrograde movements. SECTION I. Reconnaissance, organization of fires, and conduct of defense --- 56-70 64 II. Retrograde movements …_________71-72 79 III. Defense in woods-________._____ 73 81 IV. Defense in towns and villages .... 74 82 V. Defense of river line - __________… 75 83 VI. Defense against air-borne opera- tions- .-.............._____ 76 85 CHPTra 5. Caliber .30 machine-gun platoon. SECiTON I. General .----------------------77 81 88 II. Attack .-.................. 82 99 90 HI. Defense… ______.._______ 100-119 105 CHnATER 6. Caliber .30 machine-gun section and squad. SECTION I. General…--------------------- 120-126 116 II. Attack …---------------------- 127-142 118 IrI. Defense ….. .................143 152 130 CHxTER 7. 81-mm mortar platoon. SECTION I. General …---------------------- 153-158 137 II. Attack-_…--------------------…- 159-176 140 III. Defense …........._….... 177-194 152 CHAPTr 8. 81-mm mortar section and squad. SECTION I. General -__------------____---- 195-202 162 1I. Attack ----------------------- 203-217 165 III. Defense __.------------____ --__ 216-231 174 CHnArER 9. Administration. SECTION I. Supply _-_------_------------- 232-241 179 II. Medical service and evacuation__ 242-245 193 II. Motor maintenance -___.-------- 246 194 CHAPTEn 10. Signal communication _____.-..... 247-251 195 APPENnxx I Individual protection; emplacements for heavy machine guns and 81-mm mortars: observation posts; and hints on camouflage_ .--_____-_-- . 1-6 200 II. Directives for tactical training of heavy weapons company .-------- 1-8 230 ....... I .................... U- 263 Il FM 7-15 INFANTRY FIELD MANUAL HEAVY WEAPONS COMPANY, RIFLE REGIMENT CHAPTER 1 GENERAL Paragraphs SWcrToNI. Composition, armament and equipment .------ 1-6 II. Tactical employment of heavy weapons company__ 7-18 SECTION I COMPOSITION, ARMAMENT, AND EQUIPMENT U 1. COMPOSITION.-a. Company.-The heavy weapons com- pany consists of a company headquarters, two caliber .30 heavy machine-gun platoons, and one 81-mm mortar platoon. (See fig. 1.) For details of organization, armament, and equip- ment, see Tables of Organization and Table of Basic Allow- ances. b. Company headquarters.-(1) The company headquar- ters is composed of a command group and an administration group. (2) The command group consists of the company com- mander, reconnaissance officer, first sergeant, reconnaissance and signal sergeant, transport sergeant, motor mechanics, bugler, orderly, and messengers. Chauffeurs who drive the command trucks assigned to company headquarters, and basic privates, are included in the command group. (3) The administration group consists of the supply ser- geant, mess sergeant, cooks and cooks' helpers, armorer- artificer, and the company clerk. c. Platoons.-For composition, refer to figure 1 and see paragraphs 78 and 154. 1 INFANTRY FIELD MANUAL HEAVY WEAPONS COMPANY SODSODC SEC IMG SBOWNING CAL. 30 I MORTAR. I MM. M1917 lIun .1-Cormposltlonof heavy weapons company. (See T/O 7-18.) * 2. CAPABILITIES AND LIMITATIONS OF HEAVY MACBINE GUN.- The caliber .30 heavy machine gun is a crew-served weapon capable of delivering a large volume of continuous fire. Medium rate of fire (125 rounds per minute) can be sus- tained indefinitely. Rapid fire (250 rounds per minute) can be fired for several minutes, but steaming will occur Within 2 or 3 minutes. Because of its fixed mount, the heavy machine gun is capable of delivering overhead fires and of firing accu- rately at night from predetermined data. Due to the length of the beaten zone (horizontal pattern of dispersion) enfilade fire is the most effective type of fire delivered by this weapon. When overhead fires are not possible or desirable, fires are directed through gaps between riflemen or groups of riflemen. Gaps may be created and maintained for such fire. a. Mobility.-After being removed from its weapon carrier, the heavy machine gun and its crew have the same sustained mobility for a considerable distance as have riflemen. Even- tually, however, fatigue will cause the crew to fall behind, beyond supporting distance. Hand-carry of ammunition for distances much in excess of 500 yards greatly increases the problem of maintaining an adequate supply of ammunition at the gun. Weapon carriers must be used, therefore, to the limit of their capabilities in transporting the machine guns 2 HEAVY WEAPONS COMPANY, RIFLE REGIOZENT 2-3 and supplying them with ammunition. See limitations on the use of weapon carriers, paragraph 6b (2). b. Ranges.-(1) The effective range of the machine gun, employing direct fire, is limited by observation. Observation will rarely be effective beyond 2,000 yards. (2) The effectiveness of the machine gun, employing indi- rect fire, is limited by its maximum effective range and by the facilities for obtaining accurate firing data. (See FM 23-45 and 23-55.) c. Vulnerability.-An enemy will search for the location of machine guns. The distinctive noise of firing, the muzzle blast, dust clouds caused by firing, and the silhouette of the gun, all tend to disclose its location. Therefore, firing posi- tions should, whenever practicable, be selected in position defilade or partial defilade. See paragraph 25b (3) and figures 7, 8, and 9. When time permits, the machine gun should be well dug in. For machine-gun emplacements, see appendix I and figures 28, 29, and 30. d. Targets.-The hostile target most dangerous, at the moment, to friendly troops is the primary target. Suitable targets are- (1) Exposed personnel, particularly if in close formation, or in depth with respect to the line of fire. (2) Intrenched personnel, observation posts, machine guns, or antitank guns, for destruction or neutralization. Neutral- ization is accomplished by hampering or interrupting move- ment or action, and thereby reducing or destroying the com- bat efficiency of the target. (3) Low-flying airplanes. The effective slant range of heavy machine guns against low-flying airplanes does nol exceed 1,000 yards. For antiaircraft fires, see paragraph 18. (4) Mechanized vehicles. For conduct of crews and fire against mechanized vehicles, see paragraph 18. i 3. CAPABILITIES AND LIMITATIONS OF 81-MM MORTAR.-The 81-mm mortar is a crew-served weapon. Each mortar is capable of firing an effective concentration in an area 100 by 100 yards. The use of the mortar for firing concentrations is limited by the supply of ammunition. (See FM 23-90.) a. Mobility.-The 81-mm mortar has approximately the same mobility as the heavy machine gun. Its ammunition 3 3 INFANTRY FIELD MANUAL supply is more difficult, both because of the weight of the projectile and because of the rapidity with which the initial supply may be exhausted. b. Ranges.-The effective range is limited by observation rather than by the maximum range of the weapon. The range of the light shell is from 100 to 3,300 yards; the range of the heavy shell is from 300 to 2,650 yards. Effective ob- servation, however, will rarely be obtained beyond 2,000 yards. Mortar fires should not be placed less than 200 yards from friendly troops. c. Vulnerability.-Due to its high-angle trajectory and effective range, a wide choice may be exercised in the selec- tion of firing positions, provided observation is available. Advantage should be taken of deep defilade, or of woods which afford openings through which the mortar can fire. Firing positions should be selected which protect the crew from the fires of rifles and machine guns, and reduce the vulnerability of the mortar and crew to hostile artillery fires and air attack. However, each firing position must be suffi- ciently close to its observation post to permit effective control of fires with available means of signal communication. (See par. 198.) d. Targets.-The necessity for conserving ammunition sup- ply demands careful selection of mortar targets, particularly In offensive combat. Suitable targets are- (1) Located, or approximately located, hostile machine guns, mortars, and antitank guns. (2) Observed point or small area targets protected from effective fire of rifles and machine guns, such as personnel or weapons in road cuts, embankments, or intrenchments. Re- verse slopes and woods, which afford approaches defiladed from the fire of rifles and machine guns, are suitable targets in defensive combat. In offensive combat, reverse slopes and woods also are suitable targets in harassing a retreating enemy, or to disrupt known or suspected movement or assem- bly of reserves. However, priority is always given to observed targets. (3) Positions having overhead cover-heavy shell only. (4) Areas to be smoked in order to deny hostile observa- tion.