WOUND BALLISTICS Presented by Paul Ley Beirut, Lebanon ICRC orthopedic surgeon May 12, 2017 RED CROSS MEMORIAL IN SOLFERINO 1859 Solferino San Martino LORENTZ BULLETS MOD.1854 USED AT SOLFERINO Cal 13,70mm w 30g KALASHNIKOV BULLET USED AT BANGUI Cal 5,45x39 w 3,5g INTERNAL BALLISTICS BLACK POWDER COMBUSTION SMOKELESS POWDER COMBUSTION 40% OF INITIAL MASS LEFT AS RESIDUE ALMOST COMPLETE – VERY LOW RESIDUE BARREL FOULING HIGH EFFICIENCY AND HIGHER TEMPERATURE AND PRESSURE LOW EFFICIENCY SMOKELESS POWDER Advantages: PROBLEM • higher muzzle velocity • flatter trajectory The lead bullet, under high • longer range pressure, is deforming and • smaller cartridges leaves a deposit along the • less conspicuity of isolated internal part of the snipers barrel.The accumulation of • less fouling this lead deposit can lead to dangerous situations of barrel obstruction IN ORDER TO AVOID THIS THE FIRST JACKETED LEAD DEPOSIT PROBLEM, BULLETS WERE BORN SOME SORT OF PROTECTION OF THE LEAD BULLET WAS NECESSARY TODAY KNOWN AS FULL METAL JACKET BULLET A ZINC AND COPPER CASING WAS TESTED SUCCESSFULLY 1859 Battle of Solferino: birth of the idea of the Red Cross 1863 Creation of the ICRC First Geneva Convention 1864 St Petersburg Declaration 1868 1871 577 Martini_Henry rifle Smokeless powder 1888 303 Lee-Metford with Mark I 1891 303 Lee-Metford with nitro powder Mark II Tip of casing is sawed off 1895 Chitral Campaign : NW frontier; bullets INEFFECTIVE Capt. Neville Bertie-Clay at DUM DUM (Bengal) 1897 developped an improved version of Mark II 1898 Battle of Omdurman (sudan): Mark IV (woolwich) HIGHLY EFFECTIVE The Hague Conference 1899 Boer War (south africa) THE DUM DUM BULLET AND THE “BARBARIANS” 1859 Battle of Solferino: birth of the idea of the Red Cross 1863 Creation of the ICRC First Geneva Convention 1864 St Petersburg Declaration 1868 1871 577 Martini_Henry rifle Smokeless powder 1888 303 Lee-Metford with Mark I 1891 303 Lee-Metford with nitro powder Mark II 1895 Chitral Campaign : NW frontier; bullets INEFFECTIVE Capt. Neville Bertie-Clay at DUM DUM (Bengal) 1897 developped an improved version of Mark II 1898 Battle of Omdurman (sudan): Mark IV (woolwich) HIGHLY EFFECTIVE The Hague Conference 1899 Boer War (south africa) THE DUM DUM BULLET AND THE “BARBARIANS” The dum-dum bullet was finally outlawed at the hague peace conference in 1899 BY THE END OF THE XIXth CENTURY THE BASIC HUMANITARIAN CONCEPT OF UNNECESSARY SUFFERING WAS ESTABLISHED THE USE OF “HUMANE” BULLETS i.e. FULL METAL JACKETED BULLETS BY THE MILITARY BECAME AN OBLIGATION ANATOMY OF A CARTRIDGE Bullet Case Propellent Primer Rifle TWO BASIC COMPONENTS OF A FULL METAL JACKET BULLET Lead core Metal casing SHOTGUN CARTRIDGES From B.Kneubuehl “wound ballistics” SHOTGUN CARTRIDGE Fabric wad Plastic wad THE WAD IS FOUND VERY OFTEN DEEP IN THE WOUND IN CLOSE RANGE SHOTS BOTH PLASTIC AND FABRIC WADS ARE NOT VISIBLE ON X-RAY IMAGES BULLETS FRAGMENTS SHOT EXTERNAL BALLISTICS STUDY OF THE BULLET IN FLIGHT WITH NO OTHER FORCES ACTING ON IT EXCEPT GRAVITY AND AIR RESISTANCE Weight and air drag tend to destabilize the bullet Non spinning bullet Air drag s g Flight path weight The only forces acting on a bullet in flight are its weight and the air drag THE “LATTOO” EXAMPLE NO ROTATION HIGH SPEED ROTATION (SPINNING) DUE TO SPINNING THE TOP’S AXIS IS THE TOP JUST FALLS TO THE SIDE STABILIZED BY GYROSCOPIC EFFECT RIFLING GROOVES LANDS THE TWISTING SHAPE OF THE RIFLING IMPARTS A SPINNING MOVEMENT TO THE BULLET Spinning along bullet axis induces a gyroscopic stabilizing moment which tends to bring back the Spinning and stability bullet axis parallel to flight path Air drag s Ψ g Flight path The bullet is stable if the moment induced by spinning (red arrow) is greater than the moment induced by air drag (blue arrow) Position of center of gravity along the bullet longitudinal axis • bullet’s shape • Variable density of innercore material weight Modern military bullets tend to a have a rearward center of gravity better condition for tumbling in body tissue The AK-74 bullet 5,45x39 This bullet has an empty cavity at its tip. At impact, the posterior steel penetrator pushes the lead mass forward , displacing the center of gravity and creating better tumbling characteristics. Ultimately, a greater amount of energy can be transferred to the target due to this early tumbling TERMINAL BALLISTICS INTERACTION OF BULLET WITH TARGET WOUNDING MECHANISM BASIC PRINCIPLE OF TERMINAL BALLISTIC THE DAMAGE, CREATED BY A FLYING BULLET HITTING BODY TISSUES, IS THE RESULT OF KINETIC ENERGY ( E = ½.M.C2 ) TRANSFERRED FROM THE BULLET TO THE TISSUES Kinetic energy of bullets (1) 3500 3000 2500 ) 2000 Joules 1500 E ( 1000 500 0 9mm 9mm 5,45x39 5,56x45 7,62x39 7,62mm makarov luger AK-74 M 193 AK-47 NATO BLUE : energy at point blank RED : energy at 150m for the handguns calibers (the two 9mm) and at 300m for the rifles ammunitions YELLOW : minimum level of energy to create significant body damage (ca.150 J) Kinetic energy of bullets (2) 18000 16000 14000 12000 ) 10000 point blank Joules 8000 E ( 300m 6000 800m 4000 2000 0 7,62mm NATO .50 BROWNING calibers BLUE : energy at point blank RED : energy at 300m YELLOW : minimum level of energy to create significant body damage (ca.150 J) WOUND PROFILES Wound profiles allow a good visualization of bullet behavior in a homogeneous medium. They do NOT represent exactly what happens in human tissues but they help understand important wounding mechanisms and provide a good comparative analysis of different bullet terminal ballistics WOUND PROFILES GELATINE ( “elastic”) TISSUE SIMULANTS GLYCERINE SOAP (“plastic”) Bone and vessels simulants can be added WOUND PROFILES High-speed images of bullet through GELATINE WOUND PROFILES Wound profiles are obtained by shooting through a GLYCERINE SOAP block GLYCERINE SOAP Plastic deformation The block is cut along its longitudinal axis The “profile” of the cavity left after the bullet’s passage represents the temporary cavity and ITS VOLUME THE AMOUNT OF ENERGY TRANSFERRED (Martell’s Law) THE TUMBLING MECHANISM Temporary cavity neck Permanent cavity WHEN TUMBLING STARTS, TRANSFER OF ENERGY INCREASES ABRUPTLY WOUND PROFILES Vetterli 10,4mm Vel. 400m/s Wt. 19,4 gm Typical WP of a military bullet ,in use around 1850-1890. Although the velocity ( ≈400m/s) is less than half that of modern assault rifles, the permanent cavity is quite important. This is due to the large caliber of the bullet (10,4mm) and to the fact that it ismade of lead the importance of “mushrooming” WOUND PROFILES Nato cal. 7,62x51 FMJ Vel. 815 m/s Temporary cavity Wt. 9,5 g neck Permanent cavity Standard Nato forces caliber. Replaced by the M-193., but still widespread worldwide and used in light machine-guns. Compare with 7,62 soft point (.308 win) WOUND PROFILES .308 win (7,62 SP) Vel. 815 m/s Wt. 9,5 g Typical WP of a “mushrooming” bullet with a very short neck MEASURING THE WOUND POTENTIAL The volume of the cavity in tissue simulant corresponds to the amount of energy transfer (Martell’s Law) and thus to the wounding potential • Identical bullets in terms of weight and .308 win (SP) velocity, thus carrying the same kinetic energy • the difference in wound potential is due 7,62x51 (FMJ) to the fact that one bullet is soft pointed ENERGY TRANSFER and the other is full metal jacketed DEPTH OF PENETRATION WOUND PROFILES AK-47 7,62x39 Vel. 708 m/s Wt. 8 g WP of the “Kalashnikov”. Despite a double tumbling profile, the length of the neck is similar to that of the 7,62 nato 2 KALASHNIKOV BULLETS AK-47 AK-74 7,62x39 5,45x39 WOUND PROFILES AK-74 5,45x39 Vel. 910 m/s Wt. 3,45 g Example of small caliber, high velocity bullet developed by Soviet forces in the ‘70s. At impact, the empty cavity at the tip of the bullet is filled with lead that is pushed forward by the steel penetrator. This “internal deformation” creates a highly unstable bullet that tumbles almost immediately neck is less than 2 cm, note also the double tumbling and the 90 deviation at the track’s end WOUND PROFILES M-193 5,56x45 Temp cav Vel. 960 m/s Wt. 3,56 g Perman cav Neck WP of the bullet fired by the M-16 , widely used by US forces in the Vietnam war. At short range , this full metal jacket bullet sometimes breaks apart (at the cannelure level), but beyond 180 meters it behaves like the AK-74’s bullet THE RICOCHET A bullet may hit an obstacle before reaching its intended target. It is then destabilized and will hit the target in a particular way. This is called the “ricochet” effect and is demonstrated by having the bullet just grazing a wooden stick before the target, which is hit with the bullet travelling sideways and creating a WP compatible with an immediate and very large transfer of energy WOUND PROFILE OF A RICOCHET EFFECT 10 cm WOUNDING MECHANISM CRUSHING DIRECT ACTION OF THE BULLET PERMANENT CAVITY TISSUES ARE STRETCHED RADIALLY AND OUTWARDLY TEMPORARY CAVITY STRETCHING WITH RESPECT TO THE BULLET PATH BALLISTIC WOUNDS KEYPOINTS • ASPECT OF THE WOUND IS VARIABLE • THE AMOUNT OF DAMAGE IS VARIABLE • SEVERE DAMAGE OF DEEP TISSUE CAN OCCUR WITH SMALL ENTRY WOUNDS • TISSUE DAMAGE OCCUR AT A DISTANCE (RADIALLY) FROM THE BULLET PATH • SHELL INJURIES ARE OFTEN MULTIPLE • LARGE ENTRY WOUNDS WITH SEVERE INITIAL DAMAGE ARE OFTEN THE RESULT OF RICOCHET OR THE USE OF EXPANDING BULLETS Treat the wound, not the weapon THANK YOU .