physics of a GSW

• long barrel 


  bullet accelerated for longer down barrel = higher velocity
• short barrel


  bullet accelerated for less time = lower velocity
• kinetic energy 


  KE = mv^2/2
• bullet mass doubles


  KE increases by a factor of 2
• muzzle velocity doubles 


  KE increases by a factor of 2^2 = 4
• hollowpoint or expanding bullet 


  designed so that they deform on impact, causing more injuries
• soft-nosed bullets 


  deform on impact and transfer kinetic energy to the target
• stability of bullet in flight impacts

  accuracy, size of entrance wound, amount of damage along the wound path
• yaw 


  the rotation of the nose of the bullet during flight
• yaw is prevented by 


  making the bullet rotate
• nutation 


  nose of the bullet traces a rosette pattern as it travels along its trajectory
• precession 


  type of nutation where the nose of the bullet traces a complete circle as it travels along its trajectory
• full metal jacket 


  prevents the bullet from melting as it travels down the barrel, usually copper or nickel
• laceration 


  cut or slice of tissue caused by a sharp object
• crushing 


  first force experienced by the body before the bullet penetrates the skin
• shock wave 


  an extremely short-lived wave of intense high pressure followed by a wave of abnormally low pressure
• tissues susceptible to shockwave injury 


  muscle, liver, spleen, brain
• tissues damaged by shockwaves


  bladder, heart, bowels, eyes
• infection 


  bullet wounds usually infected immediately. reduced air pressure results in debris and bacteria being sucked in