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GUNSHOT WOUNDS. FIREARM INJURIES. FIREARMS. Smoothbore ie Shotguns ---fire mass of pellets Rifled weapons ie Handguns & Rifles---fire bullets Airguns—pistols & rifles---fire projectiles . SHOTGUNS.
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GUNSHOT WOUNDS FIREARM INJURIES
FIREARMS • Smoothbore ie Shotguns ---fire mass of pellets • Rifled weapons ie Handguns & Rifles---fire bullets • Airguns—pistols & rifles---fire projectiles
SHOTGUNS • Calibre size = Bore or Guage • Common Guages are 12 20 16 .410 • Historically,the number of balls (of barrel diameter) to equal a pound of lead • Exception is the .410,which means it has a barrel diameter of 0.410 inches
SHOTGUNS • Single-Barrelled • Double-Barrelled—may be Side-by-Side or Over-and-Under • Repeating----single-barrelled,Pump-Action or Semi-Automatic
SHOTGUNS • BARREL LENGTH • Commenest lengths • 28 inches • 30 inches • 32 inches • Legal Minimum is 24 inches • Sawn-Off Shotguns ---- ILLEGAL
SHOTGUNS • CHOKE----a constriction over last few inches of the barrel • May be built in and permanent or the gun may come with a selection of screw-in chokes • Choke functions to delay the spread of the pellet pattern
SHOTGUNS • CHOKE • True-Cylinder • Improved choke • ¼ choke • ½ choke • ¾ choke • Full choke
SHOTGUNS • AMMUNITION is the Cartridge • The Cartridge contains the lead shot (ie the pellets) which come in a variety of sizes • Number Convention • Low number = fewer BIG pellets • High number = more SMALL pellets • 6 = common game load
SHOTGUNS • What comes out of the gun when it is fired? • PELLETS • WADS • GAS • FLAME • POWDER---burnt and unburnt
SHOTGUN WOUNDS • CONTACT WOUNDS • Head ---- EXPLOSIVE Injury • Chest and Abdomen --- circular wounds with blackened and seared margins • May get a muzzle imprint
SHOTGUN WOUNDS • < 2 feet ----single wound, ¾ to 1 inch • 3 feet----single wound,scalloped margins • 4 feet----entrance wound + satellite holes • 10 feet----ragged central hole with numerous pellet holes • Beyond 10 feet----pattern of multiple pellet holes
SHOTGUN WOUNDS • WADDING • < 5-6 feet----goes in the entrance wound • Beyond that range , may strike separately • Felt wads • Plastic wads -----Maltese Cross between 1 to 2 feet
HANDGUNS • REVOLVERS • SEMI-AUTOMATIC PISTOLS • All fire bullets • Various Calibres
HANDGUNS • What does the weapon discharge? • Flame--- 1 to 2 inches • Gas • Powder---burnt and unburnt • Soot ( Carbon ) • Vapourised Metal • BULLET
HANDGUN WOUNDS • CONTACT WOUNDS----firm,loose,near • INTERMEDIATE Range • DISTANT
HANDGUN WOUNDS • CONTACT WOUNDS • Blackened,Seared edges • Possible Muzzle Imprint • Loose—ring of soot • Near ---broader band of blackened,seared skin
HANDGUN WOUNDS • CONTACT WOUNDS to the HEAD • May get a circular wound with blackened,seared margins • May get a wound with a muzzle imprint • May get a Stellate-shaped wound as gases enter and the thin scalp which is stretched over bone balloons out • Possible back-spatter into weapon
HANDGUN WOUNDS • INTERMEDIATE RANGE • POWDER TATTOOING is the characteristic feature • Powder grains strike the skin causing punctate abrasions • Multiple punctate reddish-brown to orange-red abrasions • Approximate range-----1/2 inch to 2-4 feet
HANDGUN WOUNDS • DISTANT • Round or Oval wounds with an Abrasion Ring (usually though not always)
HANDGUN WOUNDS • EXIT WOUNDS • Rule of ODDS and EVENS • Usually Larger and more Irregular than entry wounds • Often slit-like or stellate • N.B.---Shored Exit Wounds---uncommon---have an abrasion ring due to exit site in contact with ground or wall,or rarely due to tight clothing
GUNSHOT WOUNDS • Scientific Examination of Clothing • Test-Firing of Gun and Ammunition
RIFLE WOUNDS • POWERFUL • FMJ – Bullets ---tend to pass through and remain Undeformed • Semi-jacketed bullets used as Hunting rounds---jacket peals back and the lead core mushrooms and disintegrates into scores of lead fragments
RIFLE WOUNDS • High-Velocity Rifle wounds • Enormously powerful and destructive • Shock-Wave • Cavitation • Transmission of Energy via Fluid-filled Structures eg Arteries and Veins to produce additional injury at sites remote from the main track
GUNSHOT WOUNDS • ACCIDENT? • SUICIDE? • MURDER? • Need to consider the wound,the wound site,range of discharge,the scene etc. • Preservation of Evidence(including fingerprints) • GSR (gunshot residue) swabs • Clothing • Test-Firing