Amc week 9 ballistics email

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Amc week 9 ballistics email

  1. 1. Firearms and Ballistics
  2. 2. Revolver
  3. 3. Semi-Auto Pistol
  4. 4. How a gun works
  5. 5. Four Components of Ammunition <ul><li>Primer </li></ul><ul><ul><li>Rimmed or Centerfire </li></ul></ul><ul><li>Cartridge Case or Shotshell </li></ul><ul><li>Propellant </li></ul><ul><li>Projectile(s) </li></ul>
  6. 6. Ammunition
  7. 7. Ammunition
  8. 8. PREMIUM LOAD with SHOTCUP Pellets do not contact bore
  9. 11. Some problems
  10. 12. Stable vs. Instable Projectile Flight
  11. 13. Rifling
  12. 17. <ul><li>When a firearm is manufactured, the individual parts are made with tools that are in a constant state of change </li></ul><ul><li>As a result, no two guns will leave the same marks on the ammunition components </li></ul><ul><li>The marks found on bullets are sometimes referred to as striations </li></ul>
  13. 20. The match on the bullet
  14. 21. <ul><li>Firearmsid.com </li></ul><ul><li>[email_address] </li></ul><ul><li>9v2nww45 </li></ul>
  15. 23. Gunshot Residue
  16. 24. Source of Gunshot Residue <ul><li>Firing a weapon may cause microscopic particles of primer residue and gunpowder to be deposited on the hands of the shooter </li></ul><ul><li>The higher the caliber, the more GSR depositied on hands </li></ul><ul><li>.22 caliber rim-fire cartridges will sometimes not show traditional GSR particles </li></ul>
  17. 25. Primers <ul><li>Lead Styphnate </li></ul><ul><ul><li>Primary explosive </li></ul></ul><ul><li>Barium Nitrate </li></ul><ul><ul><li>Oxygen Source </li></ul></ul><ul><li>Antimony Sulfide </li></ul><ul><ul><li>Fuel </li></ul></ul>
  18. 26. Formation of the Particle <ul><li>Upon detonation, the compounds of the primer vaporize, mix and then condense back into particles </li></ul><ul><li>The result: what was once three separate particles have become one particle made up of lead, barium and antimony </li></ul>
  19. 27. Inside a GSR kit <ul><li>Each GSR kit contains </li></ul><ul><ul><li>Instructions </li></ul></ul><ul><ul><li>A pair of rubber gloves </li></ul></ul><ul><ul><li>Labels </li></ul></ul><ul><ul><li>Two sample vials </li></ul></ul><ul><li>Each vial contains adhesive coated aluminum stub mounted on the base of a rubber stopper </li></ul><ul><li>Stub pressed and lifted on the surface being sampled </li></ul><ul><ul><li>Hand </li></ul></ul><ul><ul><li>Face </li></ul></ul><ul><ul><li>Clothing </li></ul></ul>
  20. 28. The Examination <ul><li>Look for particles with the proper morphology and size </li></ul><ul><li>Look for particles which contain all three components of the primer </li></ul><ul><ul><li>Lead (Pb) </li></ul></ul><ul><ul><li>Barium (Ba) </li></ul></ul><ul><ul><li>Antimony (Sb) </li></ul></ul>
  21. 29. Scanning Electron Microscope <ul><li>Magnification ranges from 10x to 10,000x </li></ul><ul><li>Allows you to visualize GSR particles and gives you information on the elemental makeup of the particles </li></ul>
  22. 30. GSR Particle on the SEM
  23. 31. Positive: What does it mean? <ul><li>The individual fired a weapon </li></ul><ul><li>The individual handled a weapon right after it was fired </li></ul><ul><li>The individual was very near when the gun was fired </li></ul><ul><li>The individual touched a surface that had GSR on it. </li></ul><ul><li>Etc, etc, etc. </li></ul>
  24. 32. Negative: What does it mean? <ul><li>The individual did not fire a weapon </li></ul><ul><li>The individual washed their hands </li></ul><ul><li>The sample was collected after the recommended 4-6 hour time window </li></ul><ul><li>The individual was wearing gloves when they fired the weapon </li></ul><ul><li>Etc, etc, etc. </li></ul>
  25. 33. Lead Poisoning
  26. 34. Bullet Trajectory
  27. 35. Projectile Penetration <ul><li>Three Possibilities </li></ul><ul><ul><li>Projectile is stopped by impact without penetration </li></ul></ul><ul><ul><li>Projectile will penetrate the object without exiting </li></ul></ul><ul><ul><li>Projectile will pass through object (Perforate) </li></ul></ul>
  28. 36. Definitions <ul><li>Penetration </li></ul><ul><li>Penetration is when a projectile enters but does not exit. Not to be confused with Perforation </li></ul><ul><li>Perforation </li></ul><ul><li>Perforation is when a projectile passes through and through. Not to be confused with Penetration </li></ul>
  29. 37. Penetration and perforation The Bullets effect on sheet metal at increasing angles
  30. 38. Critical Angle and Deflection
  31. 39. Critical Angle and Deflection
  32. 43. Trajectory reconstruction using lasers
  33. 44. Laser trajectory at night
  34. 45. Shotgun Pellet Patterns In General…. For every 1” across = 1 Yard from Muzzle 7” Muzzle to Target = 7 Yards
  35. 46. Pellet Pattern Diameter vs. Range Orthogonal Impacts d d d
  36. 47. Non-Orthogonal Pellet Patterns sin -1 (d/D) = incidence angle
  37. 48. Orthogonal Strikes No. 4 Buck 12-ga. d = 7 in.
  38. 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
  39. 50. LEFT vs RIGHT
  40. 51. RIFLING TWIST DETERMINATION from RICOCHET MARKS on SMOOTH, HARD SURFACES The “ Chisum” Trail
  41. 52. 230-gr. .45 Auto FMJ-RN Incident Angle = 10 0 Surface = Smooth Steel Ricochet Angle = 1.4 0 13 0 profile views
  42. 53. Three 50-gr. FMJ .25 Automatic Bullets Ricocheted from a Hard, Unyielding Surface after Low (less that 5 0 ) Incident Angle Impacts
  43. 54. Cartridge Case Ejection Patterns <ul><li>Each Firearm is Different </li></ul><ul><ul><li>Ammunition </li></ul></ul><ul><ul><li>Ground Surface </li></ul></ul><ul><li>Shooter’s Stance Does Not Matter </li></ul><ul><ul><li>Weaver vs. Prone </li></ul></ul><ul><ul><li>Grip doesn’t matter </li></ul></ul><ul><li>How the Gun is Held Matters </li></ul>
  44. 55. Ejection Patterns X
  45. 56. Bullets and Glass
  46. 57. BB Impact
  47. 62. Effects of Projectiles on Common Materials <ul><li>Laminated </li></ul><ul><li>Glass </li></ul>
  48. 65. Laminated Auto Glass
  49. 66. What else can be matched?
  50. 68. Extractor and Breech

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