BALLISTICS part 1 - cpb-eu-w2.wpmucdn.com€¦ · WOUND BALLISTICS Presented by Paul Ley ICRC...
Transcript of BALLISTICS part 1 - cpb-eu-w2.wpmucdn.com€¦ · WOUND BALLISTICS Presented by Paul Ley ICRC...
WOUND BALLISTICS
Presented by Paul Ley ICRC orthopedic surgeon
Beirut, Lebanon May 12, 2017
RED CROSS MEMORIAL IN SOLFERINO
Solferino
San Martino
1859
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
40% OF INITIAL MASS LEFT AS RESIDUE
BARREL FOULING AND
LOW EFFICIENCY
SMOKELESS POWDER COMBUSTION
ALMOST COMPLETE – VERY LOW RESIDUE
HIGH EFFICIENCY HIGHER TEMPERATURE AND PRESSURE
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
IN ORDER TO AVOID THIS LEAD DEPOSIT PROBLEM,
SOME SORT OF PROTECTION OF THE LEAD BULLET WAS NECESSARY
A ZINC AND COPPER CASING WAS TESTED
SUCCESSFULLY
THE FIRST JACKETED BULLETS WERE BORN
TODAY KNOWN AS FULL METAL JACKET
BULLET
THE DUM DUM BULLET AND THE “BARBARIANS”
1871
1888
1891
1895
1897
1898
1868
1899
St Petersburg Declaration
The Hague Conference
577 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)
Smokeless powder
1864
1859 Battle of Solferino: birth of the idea of the Red Cross
First Geneva Convention
1863 Creation of the ICRC
Tip of casing is sawed off
THE DUM DUM BULLET AND THE “BARBARIANS”
1871
1888
1891
1895
1897
1898
1868
1899
St Petersburg Declaration
The Hague Conference
577 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)
Smokeless powder
1864
1859 Battle of Solferino: birth of the idea of the Red Cross
First Geneva Convention
1863 Creation of the ICRC
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
Case
Bullet
Propellent
Primer
Rifle
ANATOMY OF A CARTRIDGE
Lead core
Metal casing
TWO BASIC COMPONENTS OF A FULL METAL JACKET BULLET
SHOTGUN CARTRIDGES
From B.Kneubuehl “wound ballistics”
Plastic wad
Fabric wad
SHOTGUN CARTRIDGE
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
Flight path
Air drag
g
s
weight
The only forces acting on a bullet in flight are its weight and the air drag
Non spinning bullet
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
RIFLING
GROOVES
LANDS
THE TWISTING SHAPE OF THE RIFLING
IMPARTS A SPINNING MOVEMENT TO THE
BULLET
Spinning and stability
Spinning along bullet axis induces a gyroscopic
stabilizing moment which tends to bring back the
bullet axis parallel to flight path
Flight path
Air drag
Ψ
The bullet is stable if the moment induced by spinning (red arrow) is greater than the moment induced by air drag (blue arrow)
s
g
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 )
T R A N S F E R R E D
FROM THE BULLET TO THE TISSUES
0
500
1000
1500
2000
2500
3000
3500
9mmmakarov
9mmluger
5,45x39AK-74
5,56x45M 193
7,62x39AK-47
7,62mmNATO
E (
Jou
les)
Kinetic energy of bullets (1)
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)
0
2000
4000
6000
8000
10000
12000
14000
16000
18000
7,62mm NATO .50 BROWNING
E (J
ou
les)
calibers
Kinetic energy of bullets (2)
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)
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
TISSUE SIMULANTS
GELATINE ( “elastic”)
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
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)
GLYCERINE SOAP
THE TUMBLING MECHANISM
neck
Temporary cavity
Permanent cavity
WHEN TUMBLING STARTS, TRANSFER OF ENERGY INCREASES ABRUPTLY
WOUND PROFILES
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”
Vetterli 10,4mm Vel. 400m/s Wt. 19,4 gm
WOUND PROFILES
Nato cal. 7,62x51 FMJ Vel. 815 m/s Wt. 9,5 g
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)
neck
Temporary cavity
Permanent cavity
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 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)
ENERGY T
RANSFER
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
AK-47 7,62x39
AK-74 5,45x39
2 KALASHNIKOV BULLETS
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
Temp cav
Perman cav
Neck
M-193 5,56x45 Vel. 960 m/s Wt. 3,56 g
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
10 cm
WOUND PROFILE OF A RICOCHET EFFECT
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
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