Firearm injuries

Contains lecture ppt of Firearm

1. Firearm Injuries Dr. Tikendra Dewangan MD ( Forensic Medicine) RIMS Raipur

2. What is a firearm? A firearm is any weapon which discharges a missile by the expansive force of the gases produced by burning of an explosive substance.

3. What is ballistics ? a Ballistics is the science dealing with firearms, ammunition and the effects from their use.

4. Proximal ballistics. Motion of projectile Within the firearm Intermediate ballistics. Motion of projectile outside the firearm Terminal ballistics/Wound . Effect of projectile on target/Body

5. Classification According to the condition of barrel. According to firing action. According to barrel length. According to muzzle velocity According to Manufacturing process.

6. I. According to the condition of barrel

7. Some Terminology Barrel: The metal tube through which the bullet is fired Steel tube for jetting of the projectile. Two ends --- Breach & Muzzle Bore: The inside of the barrel  Smooth bore: Shotguns.  Not smooth bore: rifles, pistols Breach end Muzzle end

8. Helixometer – device used to measure internal diameter of barrel or is the instrument to examine the interior of the barrel.

9. Rifled Firearm Rifling means the inner surface of bore of the weapon from breech to the muzzle end is thrown into spiral grooves , varying from 2 to 22 or more (usually 4–7), which run parallel to each other but are twisted spirally. These ‘grooves’ are called ‘rifling’ and the projecting ridges between these grooves are called ‘lands’. Caliber- Ex .22, .30, .32, .45 Caliber

10. What does rifling do to the bullet? LAND GROOVE Gives the bullet a spinning or spiraling motion. A greater power of penetration. A straight course and prevents it from unsteady movement as it travels in the air.

11. Marking in bullet Primary marking ( Class characteristics) – Due to rifling Each company has different no. of rifling, their width, depth etc. Indicate making & model of Gun Seen by naked eye Secondary Marking ( Individual characteristics) – Individual variation in each gun Due to repeated wear & tear in each gun Due to Cleaning of gun Seen by Microscope

12. Smoothbore firearm No rifling Bore- Internal diameter of shotgun Internal diameter of shotgun expressed by a system k/as – Gauge No. of lead balls, each fitting the bore, which can be made from 1 pound (454gm) of lead

13. Choking : It is in the form of small Constriction at the muzzle end of shot gun . Degree of choking is based upon the percentage of pellets that will stay inside a 30 inch circle at 40 yards Paradox gun- In some shotgun rifling is done near muzzle end. Smoothbore firearm

14. MLI OF CHOKING 65%- 75% of pellet in circle- Full choke Increasing the muzzle velocity of projectile. Maintain shot to remain together for long distance Enhances the explosive force

15. AIR PISTOL: Compressed air is used to fire the missile In some weapons liquid CO2 is used as propellant PEN GUNS : used for firing tear gases but can be modified to fire ordinary cartridge ZIP GUNS : H ome made rifled firearm that is used to fire single shot. STUD GUNS: used to fire metal studs into wood, concrete, steel.

16. CARTRIDGE Single Unit of ammunition.

17. CARTRIDGE Pellets/shots Wad/Card board Disc Gunpowder primer Bullet Gun powder Primer Jacket SHOTGUN RIFLE

18. CARTRIDGE (SHOT GUN)

19. CARTRIDGE (Rifle)

20. Wad - keeps the things apart or in place. Here, it may be made up of cardboard/ cork/plastic etc

21. CARTRIDGE FIRING SEQUENCE CARTRIDGE FIRING SEQUENCE CARTRIDGE IN CHAMBER FIRING PIN STRIKES PRIMER OR CASE RIM AND IGNITES THE PRIMING COMPOUND FLAME GENERATED BY PRIMING COMPOUND IGNITES POWDER CHARGE POWDER BURNS RAPIDLY, GENERATING A VOLUME OF HOT, HIGH-PRESSURE GAS GAS PUSHES BULLET THROUGH BORE AT HIGH SPEED BULLET EXITS MUZZLE, HOT GAS MAKES “BANG”

22. Firing

23. Primer ( Detonator) Most common following ingredients are used… Tetrazene Lead Syphnate, Antimony Sulphide Barium nitrates BLAST Percussion Cap: Primer stored into small compartment attached to the base of the cartridge case. which made up of copper or zinc

24. RIMFIRE CARTRIDGE PRIMING COMPOUND IS CONTAINED IN THE INSIDE OF THE RIM OF THE CASE HEAD Primer RIMFIRE AND CENTER-FIRE CARTRIDGES CENTERFIRE CARTRIDGE PRIMING COMPOUND IS CONTAINED IN A METAL CUP, CALLED A PRIMER, IN THE CENTER OF THE CASE HEAD

25. Propellant (Gun powder) This is situated in close proximity to the primer within the cartridge case. Types of gun powder : 1. Black Powder 2. Semi smokeless powder 3. Smokeless

26. Gun Powder Black powder is a granular mixture of potassium nitrate (KNO 3 ) 75% Which supplies oxygen for the reaction Charcoal 15% Which provides carbon and other fuel for the reaction Sulfur (S) 10% Which, serving as a fuel , lowers the temperature required to ignite the mixture, thereby increasing the rate of combustion

27. Gun Powder Semi smokeless Powder It is a mixture of 80% Black powder and 20% Smokeless powder Smokeless powder It is contain Nitrocellulose, Nitroglycerin or Nitroguanidine Three types: Single based: Nitrocellulose alone Double based Nitrocellulose & Nitroglycerin Triple based Nitrocellulose , Nitroglycerin, and Nitroguanidine

28. Gun Powder BLACK POWDER SMOKELESS POWDER 1 Grain on combustion produce 200-300 cc of gas. 1 Gram on combustion produce 3000 – 4500 cc of gas More the no of F more fine the gun powder Ex- FG, FFG, FFFG 1 Grain on combustion produce 800-900 cc of gas. 1 Gram on combustion produce 12000 – 13000 cc of gas

29. Projectile This is usually either a Bullet or a bunch of pellets(shot). 1. Projectile - Bullet (Rifled Weapons) 2. Projectile - Pellets (Smooth bored Weapons)

30. Projectile (Rifled Weapons) A Bullet is a projectile propelled by a firearm , sling , or air gun . Bullets do not normally contain explosives but damage the intended target by impact and penetration . The word "bullet" is sometimes used to refer to ammunition generally, or to a cartridge , which is a combination of the bullet, case/shell , powder , and primer .

31. TYPES OF BULLET

32. TYPES OF BULLET

33. Projectile (smooth Bore) Pellets (shot): These are spherical projectiles of variables size used in shotguns. No's of pellet or Spheres may varying from 6 to 2600

34. Projectile (smooth Bore) Types 1. BIRD SHOT: These are small, 1-3.5 mm in diameter It is contain 200-400 shots in a 12 bore shot gun cartridge Used for hunting very small animals likes birds 2. Buckshot : These are very large shots, 6-8 mm in diameter It is contain 9 shots in a 12 bore shot gun cartridge . It is made up by moulding so that called mould shot Used for big hunting game 3. DUST SHOT : Very small in size It is contain 2600 shots in a 12 bore shot gun cartridge

35. Components from a typical shot shell containing  birdshot and a one-piece plastic wad. Components from a typical shot shell containing  buckshot and a fiber / plastic wad combination

36. GUNSHOT WOUNDS 7/2/2021 37

37. Factors responsible for the injurious effects of missile: Factors inherent to the missile: Speed of the bullet Size and shape of the bullet Character of the missile’s movement in flight 7/2/2021 38

38. Nature of the target: Density of the target Length of tissue involvement in its course Nature of the media traversed Vitality of the part involved 7/2/2021 39 Factors responsible for the injurious effects of missile:

39. Components of Cartridge Produce injury

40. Components of Cartridge Produce injury Components Specific effects Gun Flame Heat combustion effect on garments, Hair singeing Gun smoke Soot particles Gun powder (Fine) Gun powder (Coarse) Blackening Blackening Tattooing Cards Minor injuries Wads Minor injuries Gases Blow back effect cherry red colour around wound of entry. Lead shot /Bullet Wounds of entry Exit Billiard ball ricochet effect 7/2/2021 41

41. I. Wound from Shotgun Flame – 15cm to 30cm Smoke – 30cm to 45 cm Unburnt gunpowder – 60m to 90cm Card travel for two metres Wad for 4 – 5 meters

42. Characteristic of wound Depends on the distance form which the weapon is Discharged. Contact & near contact wound Close range ( Up to 1 meter) Up to 30cm ( within the range of smoke) Up to 30cm -1 meter Up to 60 – 90 cm ( within range of gunpowder) Short range ( 1-2 metres ) - ( within the range of Card ) Intermediate ( 2- 4 metres ) – ( within the range of Wad) Distance wound ( > 4 meters) Exit wound

43. 1. Contact & near contact wound Tight contact discharge over soft tissues Single Large wound with Everted Margins Shape: irregular Singeing of hair – present due to escape of flame in loose contact Blackening : absent Soiling and burning is minimal Tattooing: absent in surrounding part but in track Muzzle impression Back spatter Cherry red/Pink tissues from carboxyhaemoglobin Wads in the depth of the wound.

44. Back Spatter

45. 2. Close range Upto one metre ----Blast effect is less Within 30 cm ----skin is singed by flame , Blackened by smoke , Tattooed by gun powder , Hairs are burnt At a distance of 60-90 cm -----single circular 2.5- 4cm diametre , only tatooing seen 30cm -1 metre —rat hole

46. 3. Short distance 1-2 metre Size of wound is 4-5cm diameter, irregular No burning , blackening, singeing of hair, tattooing Wad inside body

47. 4. Intermediate range 2-4 metres Shot mass begin to spread at 2 metres Individual pellet holes detected Wad just strikes the body >3 metres - central aperture with small openings in 8-10cms

48. 5. Distant range > 4 metres All shot penetrate separately in an area of 10-15 cms Death beyond 30 meters is rare.

49. 6. Exit wounds Usually shot gun pellets do not exit except Contact wounds Tangential wounds Thin part of body Wounds of larger calibre buckshot

50. II. Wounds from automatic pistols Flame extends up to 8 cms Smoke extends up to 30 cms Unburnt and burnt powder grains up to 60-100cms in case of rifles , 40-75cms in case of handguns

51. Contact wound Close range (shot) – 5 to 8 cm Near shot – up to 50 cm Distant shot – above 50 cm Characteristic of wound

52. 1. Contact wound:  Muzzle imprint may be present( absent ; if recoil)  Large wound with EVERTED MARGINS  Shape: irregular/ stellate / cruciate  Singeing of hair –present due to escape of flame in loose contact  Blackening/ scorching: absent  Tattooing: absent in surrounding part but in track Abrasion collar & dirt collar- present “ Cherry red” discoloration due to CO A contact shot by pistol – over top of right shoulder region:  cruciate shape due to cavitation as a result of blast effect  “Cherry red” discoloration due to CO

53. The abrasion ring , and a very clear muzzle imprint , are seen in this contact range gunshot wound . 7/2/2021 59 Muzzle mark local burning of the skin Cherry red

54. 2. Close range Entry wound on back of chest just left to midline (Level- T5-T6):  Large circular  Scorching/ blackening- Present  Tattooing-Present Within range of flame( 8 cm) – also termed as POINT BLANK Size - Little large( than bullet ), circular shape Margins inverted Abrasion ring & dirt ring Blackening/ scorching, singeing of hair PRESENT Tattooing

55. 7/2/2021 61 Tattooing

56. Formation of abrasion collar & inversion of margins in case of entry wound

57. 3. Near range Outside range of flame & smoke ; within range of gun powder i.e upto 50cm Small round hole Smaller than size of bullet Margins inverted Dirt ring - Present Blackening/ scorching, singeing of hair - Absent Tattooing - Present

58. 4. Distant range  Out side range of flame, Smoke and powder (above 50 cm)  Entry wound is Smaller than the size of bullet Circular in shape Abrasion collar & Grease collar is present Singeing of hair Blackening/ scorching ABSENT Tattooing

59. Summary of entry wounds Distance Contact shot Contact with skin Close shot C − in range of flame( 8 cm) – also termed as POINT BLANK Near shot within range of gun powder (8-50 cm) Distant shot Above 50 cm Muzzle imprint Present Absent Absent Absent Shape Large-Cruciate /stellate Circular Size of bullet or little more Circular Smaller than bullet Circular Smaller than bullet Margins Everted Inverted Inverted Inverted Scorching Absent Present Absent Absent Singeing of hair Present Present Absent Absent Tattooing Present in track Present Present Absent Abrasion & Dirt collar Present Present Present Absent

60. Entrance vs. Exit Wounds ENTRY WOUND EXIT WOUND Smaller than the missile – skin elasticity except in contact shot Always bigger than the missile Edges are inverted, except in contact shot Edges are everted Oval or round No definite shape “Contusion collar” or “contact ring” present “Contusion collar” absent Tattooing or smudging may be present Always absent Underlying tissues not protruding Underlying tissues may be protruding Paraffin test may be positive Paraffin test always negative 7/2/2021 67

61. A typical entrance wound Single entrance & multiple exit : Entered the body but split into several fragments, each with separate exits. Entered body orifice, producing exit. Two or more bullets have common entrance, each with separate exit. Near shot with a shotgun. 7/2/2021 68

62. B. Multiple wound of entrance & exit from single shot A bullet may pass through an arm and the chest so that four wounds result. A bullet passing through the chest or abdomen and thigh and lower leg, produces six wounds. This occurs when the person is running or sitting in an unusual position. When the body surface is irregular, such as the breast or buttocks, several re-entries and exits can take place.

63. C. Entrance Wound Is Present But Bullet Is Not Found In The Body This occurs when the bullet entering the stomach may be vomited, entering the windpipe may be coughed up, (c) entering the mouth may be spit out, (d) entering the gastrointestinal tract may be passed out in the faeces (e) when it is so deviated or turned on coming in contact with the bone, that it passes out by the same wound as it entered.

64. D. Entry wound is more than exit : One or more bullets are not through and through, bullet lodged in the body. All bullets are through and through, one exited in natural body orifice. Different shots produced different entrances but 2 or more produced common exit. 7/2/2021 71

65. Medico legal Importance 7/2/2021 72

66. 1 .Nature of death due to firearm injury Death due to firearm injury may be suicidal, homicidal or accidental. 7/2/2021 73

67. Tests for the presence of powder residues : On the skin: Dermal nitrate test ( Paraffin test, Diphenylamine test, Lung’s test, Gonzales’ test) On clothing: Walker’s test (C-acid test, H-acid test) 7/2/2021 74

68. Gunshot wound is suicidal: Shot was fired in a closed or locked room. The death weapon is almost always found near the place where the victim was found. Muzzle of gun in contact with body part. Location of GSW accessible to wounding hand. Shot is always solitary Direction of fire compatible with trajectory of bullet. Personal history. Hand of victim may show gunpowder. Entrance wound do not usually involve clothing. Victim’s fingerprint at butt. May have suicide note. No disturbance in the place of death. 7/2/2021 75

69. ii. GSW is homicidal: Entrance has no point of election. Fired when victim at some distance from the assailant. Signs of struggle may be present. Disturbance of surroundings may be present. Wounding firearm usually not found at scene of crime. Testimony of witness . 7/2/2021 76

70. iii. GSW is accidental: Usually one shot. No special area of the body involved. Testimony of assailant, witness. 7/2/2021 77

71. 2 . The direction of the firing It is better to try to assess the direction of the firing from the dispersion of the pellets in cases of shotgun injuries and from abraded /contused and grease collars, in case of bullet injuries by rifled weapons. 7/2/2021 78

72. Distance of firing The direction of the firing 4. Identification of the firearm weapon used

73. Tests for the presence of powder residues : On the skin: Dermal nitrate test ( Paraffin test, Diphenylamine test, Lung’s test, Gonzales’ test) On clothing: Walker’s test (C-acid test, H-acid test) 7/2/2021 80

74. Tests for presence of primer components: Harrison and Gilroy Test Neutron Activation Analysis (NAA) Flameless Atomic Absorption Spectroscopy (FAAS) Use of scanning electron microscope with a linked x-ray analyzer 7/2/2021 81

75. Peculiar effects Yawning bullet. – Bullet travels in irregular fashion instead of nose-on. Tumbling bullet. – Bullet rotates end on end during its motion

76. Tandem bullet or piggyback bullet: Tandem=One behind other.

77. Ricochet bullet: Strikes intervening object.

78. Internal ricochet: Rebounds from the inner table of skull. Souvenir bullet: In the body for long time, a dense fibrous tissue capsule usually surrounds it.

79. Ricochet Bullet Dum Dum Bullet (fragments extensively upon striking) Souvenir Bullet Frangible Bullet Tandem Bullet / Piggyback / Duplex bullet (one after another) Yawning Bullet Tumbling Bullet Bullet Embolism Concealed Firearm wound Test Bullet – Fired in bullet recovery Tank made of Fresh pork skin, sand bags. Crime Bullet / Exhibit Bullet – Bullet found in body. 7/2/2021 86

80. Kennedy phenomenon: Surgical alteration of gunshot wounds makes evaluation of entrance and exit wound difficult. Rayalaseema phenomenon. Shored Exit wound

81. PUPPE’S RULE: To determine sequence of shots. It states that the fractures from the first injury develop normally, while those caused by the subsequent injury are stopped where the structure of the skull has already been deployed.