This document provides information on firearms and ballistics, including the components of ammunition, how guns work, gunshot residue, bullet trajectory, bullet penetration, shotgun pellet patterns, rifling determination from ricochet marks, cartridge case ejection patterns, and the effects of projectiles on common materials like glass. Key topics covered include the primer, cartridge case, propellant, and projectile in ammunition, as well as how examination of gunshot residue particles can provide information about whether an individual fired or handled a weapon.

1. Firearms and Ballistics

2. Revolver

3. Semi-Auto Pistol

4. How a gun works

5. Four Components of Ammunition Primer Rimmed or Centerfire Cartridge Case or Shotshell Propellant Projectile(s)

6. Ammunition

7. Ammunition

8. PREMIUM LOAD with SHOTCUP Pellets do not contact bore

11. Some problems

12. Stable vs. Instable Projectile Flight

13. Rifling

17. When a firearm is manufactured, the individual parts are made with tools that are in a constant state of change As a result, no two guns will leave the same marks on the ammunition components The marks found on bullets are sometimes referred to as striations

20. The match on the bullet

21. Firearmsid.com [email_address] 9v2nww45

23. Gunshot Residue

24. Source of Gunshot Residue Firing a weapon may cause microscopic particles of primer residue and gunpowder to be deposited on the hands of the shooter The higher the caliber, the more GSR depositied on hands .22 caliber rim-fire cartridges will sometimes not show traditional GSR particles

25. Primers Lead Styphnate Primary explosive Barium Nitrate Oxygen Source Antimony Sulfide Fuel

26. Formation of the Particle Upon detonation, the compounds of the primer vaporize, mix and then condense back into particles The result: what was once three separate particles have become one particle made up of lead, barium and antimony

27. Inside a GSR kit Each GSR kit contains Instructions A pair of rubber gloves Labels Two sample vials Each vial contains adhesive coated aluminum stub mounted on the base of a rubber stopper Stub pressed and lifted on the surface being sampled Hand Face Clothing

28. The Examination Look for particles with the proper morphology and size Look for particles which contain all three components of the primer Lead (Pb) Barium (Ba) Antimony (Sb)

29. Scanning Electron Microscope Magnification ranges from 10x to 10,000x Allows you to visualize GSR particles and gives you information on the elemental makeup of the particles

30. GSR Particle on the SEM

31. Positive: What does it mean? The individual fired a weapon The individual handled a weapon right after it was fired The individual was very near when the gun was fired The individual touched a surface that had GSR on it. Etc, etc, etc.

32. Negative: What does it mean? The individual did not fire a weapon The individual washed their hands The sample was collected after the recommended 4-6 hour time window The individual was wearing gloves when they fired the weapon Etc, etc, etc.

33. Lead Poisoning

34. Bullet Trajectory

35. Projectile Penetration Three Possibilities Projectile is stopped by impact without penetration Projectile will penetrate the object without exiting Projectile will pass through object (Perforate)

36. Definitions Penetration Penetration is when a projectile enters but does not exit. Not to be confused with Perforation Perforation Perforation is when a projectile passes through and through. Not to be confused with Penetration

37. Penetration and perforation The Bullets effect on sheet metal at increasing angles

38. Critical Angle and Deflection

39. Critical Angle and Deflection

43. Trajectory reconstruction using lasers

44. Laser trajectory at night

45. Shotgun Pellet Patterns In General…. For every 1” across = 1 Yard from Muzzle 7” Muzzle to Target = 7 Yards

46. Pellet Pattern Diameter vs. Range Orthogonal Impacts d d d

47. Non-Orthogonal Pellet Patterns sin -1 (d/D) = incidence angle

48. Orthogonal Strikes No. 4 Buck 12-ga. d = 7 in.

49. 45 0 Incident Angle with No. 4 Buck, 12 ga. d = 7 in. d/D = 0.67 Sin -1 = 42 0 Same Range as previous shot

50. LEFT vs RIGHT

51. RIFLING TWIST DETERMINATION from RICOCHET MARKS on SMOOTH, HARD SURFACES The “ Chisum” Trail

52. 230-gr. .45 Auto FMJ-RN Incident Angle = 10 0 Surface = Smooth Steel Ricochet Angle = 1.4 0 13 0 profile views

53. Three 50-gr. FMJ .25 Automatic Bullets Ricocheted from a Hard, Unyielding Surface after Low (less that 5 0 ) Incident Angle Impacts

54. Cartridge Case Ejection Patterns Each Firearm is Different Ammunition Ground Surface Shooter’s Stance Does Not Matter Weaver vs. Prone Grip doesn’t matter How the Gun is Held Matters

55. Ejection Patterns X

56. Bullets and Glass

57. BB Impact

62. Effects of Projectiles on Common Materials Laminated Glass

65. Laminated Auto Glass

66. What else can be matched?

68. Extractor and Breech