MMSC240 final

Trajectory analysis involves three areas of related ballistic study

• Internal ballistics

  • The longer the barrel, the greater the acceleration (up to a point) 

• External ballistics

• Terminal ballistics 

  • Involves defining the path of a bullet through the target surface or body, the associated damage, and the differentiating entry of exit wounds

  • Factors involved with the cause and effects produced as a result of of a bullet impacting a target surface

    • Increases in bullet velocity have greater effect on KE than increases in bullet mass

Range Determinations

• Close contact- pressed to the skin

• Close- not more than five inches from the wound

• Intermediate range- 5 - 40 inches from the wound 

Entrance Wounds

• Physical finding - unburned gunpowder - tattooing/stippling (synonymous) - characteristic marking on the skin 

Range of Fire: contact wounds- tight or loose 

• Triangular tears

• Soot

• Muzzle contusion (muzzle stamp)

• No tattooing/stippling (too close) 

Exit Wounds

• Size of the wounds does not differentiate entrance of exit wounds

• Configuration does! 

Terminology of shooting analysis

• Cartridge- single complete round of ammunition 

  • Four parts

    • Cartridge case

    • Primer

    • Powder charge

    • bullet/projectile 

• Terminus- final resting place where projectile ends up after it’s flight path (final target surface)

• French fry- compressed and punched out section of foam padding creating the shape and appearance of a french fry 

• Perforation defect- going through something

• Penetration defect- going into something 

Direction of Penetration

• In glass, a projectile hole is inevitably wider at the exit side 

Successive Penetrations

• A fracture always terminates at an existing line of fracture 

Trajectory Kits

• Includes

  • Trajectory rods 

  • Centering guides

  • Angle finders and protractors 

  • In some cases lasers