Dr_mousami_forensic_ballistics_online_class.pdf
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Dr Mousami Singh Additional Professor Department of Forensic Medicine and Toxicology KGMU, Lucknow DISCLAIMER The presentation include images which are either hand drawn or have been taken from google images or books. They are being used in presentation only for educational purp...
Dr Mousami Singh Additional Professor Department of Forensic Medicine and Toxicology KGMU, Lucknow DISCLAIMER The presentation include images which are either hand drawn or have been taken from google images or books. They are being used in presentation only for educational purpose. The author of the presentation claims no personal ownership over images taken from books or google images. Dr Mousami Singh Learning objective Describe different types of firearms including structure and components. Along with description of ammunition propellant charge and Mechanism of fire-arms Different types of cartridges and bullets and various terminology in relation of firearm– caliber , range, choking Dr Mousami Singh Describe and discuss wound ballistics- different types of firearm injuries and their interpretation Preservation and dispatch of trace evidences in cases of firearm injuries Various tests related to confirmation of use of firearms Dr Mousami Singh Dr Mousami Singh FIREARM Dr Mousami Singh AMMUNITION RIFLED CARTRIDGES SHOTGUN CARTRIDGES Dr Mousami Singh FIREARM INJURIES Dr Mousami Singh Internal Ballistics- deals with study of motion of projectile with in the firearm. External Ballistics-deals with study of motion of projectile after it leaves the firearm. Terminal Ballistics-deals with study of effect of projectile on a target. Wound Ballistics-implies the study of injuries produced in the body by the firearm. Dr Mousami Singh A Firearm is an instrument or device which forcefully ejects out a projectile through its muzzle because of expansive force of gases generated by combustion of explosive gunpowder particles. Chamber It is situated at the breach end to accommodate the cartridge. Taper/lead/leed Barrel Chamber is connected with bore through a short cone k/a taper. Bore Dr Mousami Singh It is from leed upto muzzle end of the barrel. A Firearm is an instrument or device which forcefully ejects out a projectile through its muzzle because of expansive force of gases generated by combustion of explosive gunpowder particles. Dr Mousami Singh BREACH Dr Mousami Singh BORE Breach end Dr Mousami Singh Chamber It is situated at the breach end to accommodate the cartridge. Taper/lead/leed Barrel Chamber is connected with bore through a short cone k/a taper. Bore It is from leed upto muzzle end of the barrel. Dr Mousami Singh Cut section of BREACH Dr Mousami Singh Classification The classification of guns depends on the inner side of the barrel (bore). The inner surface of some barrel is smooth or in other variety has rifling or grooves. Dr Mousami Singh Classification 1. Smooth bored weapon 2. Rifled Weapons Dr Mousami Singh Classification FIREARM 1. Smooth bored weapon 2. Rifled Weapons Dr Mousami Singh Dr Mousami Singh LANDS Dr Mousami Singh CALIBRE In rifled weapon, the bore from breach end to muzzle end is cut longitudinally in to a series of spiral grooves called rifling. No. of spiral grooves vary in no. from 2 to 20 or more. They all are parallel to one another but are cut with a twist. The raised portion in b/w the grooves inside the bore k/a lands. Dr Mousami Singh rifling In rifled weapon, the bore from breach end to muzzle end is cut longitudinally in to a series of spiral grooves called rifling. No. of spiral grooves vary in no. from 2 to 20 or more. They all are parallel to one another but are cut with a twist. The raised portion in b/w the grooves inside the bore k/a lands. Dr Mousami Singh Imparts spin to the missile Produces greater power of penetration Prevent wobbling and to give gyroscopic steadiness to the bullet during its flight straight onto its trajectory Thus rifling improves accuracy and efficiency of firing. Dr Mousami Singh Rifled weapon Smooth bored weapon Fire a single missile through Fire several lead pellets of rifled barrel standard size or a charge of shots , slugs through smooth bored barrel. Long barreled rifles with high muzzle velocity Shot guns rifles single barrel sporting rifles double barrel military rifles self loading 0.22 rifles semiautomatic Short barreled rifles with low muzzle velocity-eg.Revolver, bolt action automatic pistols. automatic Dr Mousami Singh Smooth bored weapon Dr Mousami Singh Smooth bored weapon DISPERSION Dr Mousami Singh Smooth bored weapon DISPERSION Force Pressure = Area Dr Mousami Singh Smooth bored weapon DISPERSION Force Pressure = Area Dr Mousami Singh Tapering of bore at 1½” to 2½” ( 9 to 10 cm) from the muzzle end. Degree of constriction varies from 40/1000th of an inch to 3/1000th of an inch. 1 2 3 Dr Mousami Singh Unchoked gun Improved cylinder Modified cylinder Fully choked Dr Mousami Singh Keep the charge of shots in a compact group for longer distances and decreases the rate of spread of shots. Enhance explosive force Increases the velocity overall it increases the lethal range of weapon. Dr Mousami Singh Cartridge denotes an assembled complete round of ammunition. Cartridge case Percussion cap Powder or propellant Projectile Dr Mousami Singh Cartridge of a rifled firearm Dr Mousami Singh Bullet Cartridge case Powder charge Lead peroxide Lead styphnate Tetrazene Barium nitrate Primer Antimony sulphide Pentaerythritol tetranitrate Dr Mousami Singh Percussion cap Dr Mousami Singh Projectile -Bullet Lead Momentum Softness Dr Mousami Singh Nose open Full jacketed Semi jacketed Dr Mousami Singh Wad cutter Hollow point variety Dum dum bullet Frangible bullet Incendiary bullet Tandem or piggy back bullet Tumbling bullet Souvenir bullet Dr Mousami Singh Cartridge of shotgun Retaining card board disc Charge of shots Felt wad Card board disc Gun powder Primer Percussion cap Dr Mousami Singh Wad- diameter is greater than that of the bore of gun. It prevent heat from the gunpowder from fusing or distorting the pellets. It acts like a piston and seals the bore completely,thus preventing the expanding gases from escaping and disturbing the shot charge. Felt wad contains grease ,which lubricates the bore after firing of each round. Dr Mousami Singh Buck shot (2 to 20) Bird shot(200 to 400) Dust shot (2000 to 4000) Buck shot is largest and has a diameter of 6 to 8mm Dr Mousami Singh Black powder- Charcoal 15%, Sulphur 10%, KN03 75% It is designated as FG, FFG, FFFG. More the no. of Fs , more finer the quality. Smokeless powder- Nitrocellulose ,nitroglycerine and nitroguanidine Semi-smokeless powder- 80% black + 20% smokeless Dr Mousami Singh Calibre or gauze of a gun Inner diameter of the barrel In rifled weapon, it is the diameter between the lands It is expressed in terms of cm or inch or indirect way of expression. Dr Mousami Singh Indirect expression A number is used Which is the number of spherical lead balls Which can be made of one pound of lead The size of each of which will exactly fit the inner diameter of the barrel Dr Mousami Singh 12 16 Dr Mousami Singh Example-12 bore It means that if 12 spherical balls are made out of one pound of lead then the diameter of one such ball will be equal to the inner diameter of the barrel Dr Mousami Singh Dr Mousami Singh When the trigger is pulled It will release the firing pin to strike at the percussion cap As it strike primer get detonated Resultant hot flame will inturn ignite the propellant charge in the cartridge Large amount of gas generated Will exert tremendous pressure with in confined space of cylinder As a result cartridge case swell outwards for which its hold on bullet is released. Bullet propels forwards Followed by blast of highly compressed hot gases , flame, smoke , partially burnt and un burnt powder particles, grease ,wad , cardboard discs etc. Dr Mousami Singh Blast of highly compressed hot gases Partially burnt and unburnt gun powder Flames Smoke Carbon, metal particles, grease, wad, card board disc depending on whether shot gun or bullet cartridge has been fired. Dr Mousami Singh Characteristic wound of entry Characteristic wound of exit Presence of bullet or projectile Nature of track of bullet or projectile Presence of residual products in and around the wound of entrance and recovery of bullet or pellet from the body. Dr Mousami Singh Shape Size Abraded collar Grease or dirt collar Lead or metal ring Gas ring Dr Mousami Singh Dr Mousami Singh Larger Irregular and everted margins Single/multiple No burning, singeing, blackening , tattooing, abraded collar, grease collar, metal ring or gas ring. Dr Mousami Singh Product of Rifle Pistol/revolver Shotgun combustion Flame 6"to8" 2"to3" 4"to5" Smoke 12" 8“to10" 10" Partially burnt 24" 18" 30" powder Unburnt powder 30" 24" 30" Wad × × 5 feet Dr Mousami Singh Firarm Injuries Pellets or bullets Punctured wounds Glancing wound Dr Mousami Singh Blast of highly compressed hot gases Partially burnt and unburnt gun powder Flames Smoke Carbon, metal particles, grease, wad, card board disc depending on whether shot gun or bullet cartridge has been fired. Dr Mousami Singh Product of Rifle Pistol/revolver Shotgun combustion Flame 6"to8" 2"to3" 4"to5" Smoke 12" 8“to10" 10" Partially burnt 24" 18" 30" powder Unburnt powder 30" 24" 30" Wad × × 5 feet Dr Mousami Singh Injury in case of a rifled weapon Single punctured wound of entrance Track Sometimes an exit wound too Dr Mousami Singh Injury in case of a rifled weapon Circular/oval Small in close range firing/large in distant firing Abraded and contused collar Dirt /grease collar Corona Inverted and no protrusion of fat through the wound Dr Mousami Singh Singeing of hair Scorching and burning of skin Blackening tattooing Dr Mousami Singh Contact shot Close range- with in the range of flame, smoke and gunpowder(2”-3”)(6”-8”) Near range- outside the range of flame but with in the range of smoke and gunpowder more than 6”and less than 12” more than 12”and less than 24” Distant range more than 24”(more than 2 feet) outside the range of powder deposition Dr Mousami Singh Contact shot Little or no evidence of burning, singeing, blackening and tattooing around the wound of entrance Muzzle imprint abrasion Bright pink discoloration of the muscles in the track Skull MLI Dr Mousami Singh Close shot with in the range of flame, smoke and gunpowder(2”-3”)(6”-8”) Circular/oval Small Inverted contused lacerated margins Grease collar and abraded contused collar BSBT Dr Mousami Singh Near shot outside the range of flame but with in the range of smoke and gunpowder Beyond 3inches but within 12 inches No evidence of burning and singeing Blackening will be present Tattooing will be present Dr Mousami Singh Distant shot more than 24”(more than 2 feet) outside the range of powder deposition No evidence of BSBT Dr Mousami Singh CLOSE NEAR DISTANT CONTACT RANGE RANGE RANGE Dr Mousami Singh SMOKE CLOSE NEAR CONTACT DISTANT RANGE RANGE RANGE Dr Mousami Singh CLOSE NEAR DISTANT CONTACT RANGE RANGE RANGE Dr Mousami Singh Injury in case of a rifled weapon DEPTH AND THE TRACK Dr Mousami Singh Injury in case of a rifled weapon EXIT WOUND Larger Everted with protrusion of fatty tissue Shored exit wound Punched in and punched out hole in skull Dr Mousami Singh RICOCHET BULLET WOUND Dr Mousami Singh Entrance Wounds of Shotguns Dr Mousami Singh 1. Characteristics of wound when close contact / Very near range With in few inches or cms. from the body Large lacerated wound of entrance as charge of shots will go as a single mass followed by gases. Dr Mousami Singh 1. Characteristics of wound when close contact / Very near range With in few inches or cms. from the body Large lacerated wound of entrance as charge of shots will go as a single mass followed by gases. Contused inverted margins Dr Mousami Singh 1.Characteristics of wound when close contact / Very near range With in few inches or cms. from the body Large lacerated wound of entrance as charge of shots will go as a single mass followed by gases. Contused inverted margins Size –equal or larger than the bore of the weapon Dr Mousami Singh 1. Characteristics of wound when close contact / Very near range With in few inches or cms. from the body Large lacerated wound of entrance as charge of shots will go as a single mass followed by gases. Contused inverted margins Size –equal or larger than the bore of the weapon Wad and unburnt powder particles Dr Mousami Singh Singeing of hair Burning and scorching of skin surface and tissue Blackening and tattooing may be noticed around the wound margins and mostly in depth of the wound Dr Mousami Singh If cloth in b/w no burning, singeing, blackening and tattooing Dr Mousami Singh Exit wound Larger than the wound of entrance Everted margins. No burning, blackening and tattooing Dr Mousami Singh 2. Characteristics ofentrance wound When firing range is with in 3 feet / 1 yard (approx.1mt)- Close range With in a distance of 6inches Beyond 6inches but with in a distance of 12 inches Beyond 12 inches and less than 24 inches Beyond 24 inches to 1 meter Dr Mousami Singh 2. Characteristics ofentrance wound When firing range is with in 2-3 yards or metres- SHORT RANGE Irregular lacerated central aperture Surrounded by few separate small openings by the scattered pellets Dr Mousami Singh 2. Characteristics of entrance wound When firing range is upto 4 yards or metres- INTERMEDIATE RANGE One central opening with irregular and lacerated contused margins Surrounded by several separate small openings by the scattered pellets Dr Mousami Singh Long or distant Range (above 4 metres) With increase in distance of firing the area of dispersion of pellets increases. For 1st yard the diameter is equal to the distance of firing in yards. After this distance diameter of dispersion in inches is equal to the distance of firing in yards multiplied by 1.5 Dr Mousami Singh BILLIARD BOARD RICOCHET EFFECT Dr Mousami Singh Preservation and dispatch of trace evidences in cases of firearm injuries Bullets, fragments of bullets or pellets Swab from the skin from around the entrance wound for detection of unburnt gunpowder and type of grease Torned margins of the clothes should be dried and preserved Dr Mousami Singh Medico-legal information from a firearm injury Nature of death due to firearm injury Suicidal Homicidal Accidental Dr Mousami Singh Direction of firing Distance of firing Identification of the firearm weapon used Primary markings Secondary markings Dr Mousami Singh Various tests related to confirmation of use of firearms Dermal nitrate or paraffin test Harrison and Gilroy test Spectrophotometry Atomic absorption spectroscopy Neutron activation analysis Scanning electron microscope energy dispersive X- ray analysis (SEM-EDXA) Dr Mousami Singh Dermal nitrate test or Paraffin test Nitrates and nitrites Diphenylamine and diphenyl benzidine Blue colour Dr Mousami Singh Harrison and Gilroy test Antimony Barium Lead Dr Mousami Singh Neutron activation analysis ANTIMONY COPPER Dr Mousami Singh AAS/FAAS Atomic absorption spectroscopy Flameless atomic absorption spectroscopy ANTIMONY BARIUM LEAD COPPER Dr Mousami Singh SEM-EDXA SCANNING ELECTRON MICROSCOPE ENERGY DISPERSIVE X RAY ANALYSIS GSR Dr Mousami Singh Thank You Dr Mousami Singh
