WOUND BALLISTICS. Presented by Paul Ley ICRC orthopedic surgeon. Beirut, Lebanon May 12, 2017

Transcription

1 WOUND BALLISTICS Presented by Paul Ley ICRC orthopedic surgeon Beirut, Lebanon May 12, 2017

2 RED CROSS MEMORIAL IN SOLFERINO

3 Solferino 1859 San Martino

4 LORENTZ BULLETS MOD.1854 USED AT SOLFERINO Cal 13,70mm w 30g KALASHNIKOV BULLET USED AT BANGUI Cal 5,45x39 w 3,5g

5 INTERNAL BALLISTICS BLACK POWDER COMBUSTION SMOKELESS POWDER COMBUSTION 40% OF INITIAL MASS LEFT AS RESIDUE ALMOST COMPLETE VERY LOW RESIDUE BARREL FOULING AND LOW EFFICIENCY HIGH EFFICIENCY HIGHER TEMPERATURE AND PRESSURE

6 SMOKELESS POWDER Advantages: higher muzzle velocity flatter trajectory longer range smaller cartridges less conspicuity of isolated snipers less fouling PROBLEM The lead bullet, under high pressure, is deforming and leaves a deposit along the internal part of the barrel.the accumulation of this lead deposit can lead to dangerous situations of barrel obstruction

7 IN ORDER TO AVOID THIS LEAD DEPOSIT PROBLEM, SOME SORT OF PROTECTION OF THE LEAD BULLET WAS NECESSARY THE FIRST JACKETED BULLETS WERE BORN TODAY KNOWN AS FULL METAL JACKET BULLET A ZINC AND COPPER CASING WAS TESTED SUCCESSFULLY

8 1859 Battle of Solferino: birth of the idea of the Red Cross 1863 Creation of the ICRC First Geneva Convention St Petersburg Declaration Smokeless powder Martini_Henry rifle 303 Lee-Metford with Mark I Lee-Metford with nitro powder Mark II Tip of casing is sawed off Chitral Campaign : NW frontier; bullets INEFFECTIVE Capt. Neville Bertie-Clay at DUM DUM (Bengal) developped an improved version of Mark II Battle of Omdurman (sudan): Mark IV (woolwich) HIGHLY EFFECTIVE The Hague Conference 1899 Boer War (south africa) THE DUM DUM BULLET AND THE BARBARIANS

9 1859 Battle of Solferino: birth of the idea of the Red Cross 1863 Creation of the ICRC First Geneva Convention St Petersburg Declaration Smokeless powder The Hague Conference Martini_Henry rifle 303 Lee-Metford with Mark I 303 Lee-Metford with nitro powder Mark II Chitral Campaign : NW frontier; bullets INEFFECTIVE Capt. Neville Bertie-Clay at DUM DUM (Bengal) developped an improved version of Mark II Battle of Omdurman (sudan): Mark IV (woolwich) HIGHLY EFFECTIVE Boer War (south africa) THE DUM DUM BULLET AND THE BARBARIANS

10 The dum-dum bullet was finally outlawed at the hague peace conference in 1899

11 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

12 ANATOMY OF A CARTRIDGE Bullet Case Propellent Primer Rifle

13 TWO BASIC COMPONENTS OF A FULL METAL JACKET BULLET Lead core Metal casing

14 SHOTGUN CARTRIDGES From B.Kneubuehl wound ballistics

15 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

16 BULLETS FRAGMENTS SHOT

17 EXTERNAL BALLISTICS STUDY OF THE BULLET IN FLIGHT WITH NO OTHER FORCES ACTING ON IT EXCEPT GRAVITY AND AIR RESISTANCE

18 Weight and air drag tend to destabilize the bullet Air drag s Non spinning bullet g Flight path weight The only forces acting on a bullet in flight are its weight and the air drag

19 THE LATTOO EXAMPLE NO ROTATION HIGH SPEED ROTATION (SPINNING) THE TOP JUST FALLS TO THE SIDE DUE TO SPINNING THE TOP S AXIS IS STABILIZED BY GYROSCOPIC EFFECT

20 RIFLING GROOVES LANDS THE TWISTING SHAPE OF THE RIFLING IMPARTS A SPINNING MOVEMENT TO THE BULLET

21 Spinning and stability Spinning along bullet axis induces a gyroscopic stabilizing moment which tends to bring back the 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)

22 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

23 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

24 TERMINAL BALLISTICS INTERACTION OF BULLET WITH TARGET WOUNDING MECHANISM

25 BASIC PRINCIPLE OF TERMINAL BALLISTIC THE DAMAGE, CREATED BY A FLYING BULLET HITTING BODY TISSUES, IS THE RESULT OF KINETIC ENERGY ( E = ½.M.C 2 ) T R A N S F E R R E D FROM THE BULLET TO THE TISSUES

26 E (Joules) 3500 Kinetic energy of bullets (1) mm makarov 9mm luger 5,45x39 AK-74 5,56x45 M 193 7,62x39 AK-47 7,62mm 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)

27 E (Joules) Kinetic energy of bullets (2) 7,62mm NATO.50 BROWNING calibers point blank 300m 800m BLUE : energy at point blank RED : energy at 300m YELLOW : minimum level of energy to create significant body damage (ca.150 J)

28 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

29 WOUND PROFILES TISSUE SIMULANTS GELATINE ( elastic ) GLYCERINE SOAP ( plastic ) Bone and vessels simulants can be added

30 WOUND PROFILES High-speed images of bullet through GELATINE

31 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)

32 THE TUMBLING MECHANISM Temporary cavity neck Permanent cavity WHEN TUMBLING STARTS, TRANSFER OF ENERGY INCREASES ABRUPTLY

33 WOUND PROFILES Vetterli 10,4mm Vel. 400m/s Wt. 19,4 gm Typical WP of a military bullet,in use around 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

34 WOUND PROFILES Temporary cavity Nato cal. 7,62x51 FMJ Vel. 815 m/s 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)

35 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

36 ENERGY TRANSFER 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 velocity, thus carrying the same kinetic energy the difference in wound potential is due to the fact that one bullet is soft pointed and the other is full metal jacketed.308 win (SP) 7,62x51 (FMJ) DEPTH OF PENETRATION

37 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

38 2 KALASHNIKOV BULLETS AK-47 7,62x39 AK-74 5,45x39

39 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

40 Perman cav Temp cav WOUND PROFILES M-193 5,56x45 Vel. 960 m/s Wt. 3,56 g 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

41 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

42 WOUND PROFILE OF A RICOCHET EFFECT 10 cm

43 WOUNDING MECHANISM CRUSHING DIRECT ACTION OF THE BULLET PERMANENT CAVITY STRETCHING TISSUES ARE STRETCHED RADIALLY AND OUTWARDLY WITH RESPECT TO THE BULLET PATH TEMPORARY CAVITY

44 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

45 Treat the wound, not the weapon

46 THANK YOU

47