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Ballistics:
   

            The physics of the bullet can be explained in three categories: internal ballistics, external ballistics, and terminal ballistics. I will not be looking at terminal ballistics until the next section. Looking first at internal ballistics, it is the action of the bullet from the moment the firing pin ignites the primer to the point at which the bullet exits the barrel of the gun. When the powder is ignited it creates expanding gas which begins to force the bullet through the barrel. Because there is not a significant place for the gas to escape it transfers energy to the bullet. Typically people will see higher velocities with higher peak pressures in the burn. The second area of ballistics I will discuss is external ballistics, it covers the behavior of the bullet from the time it exits the barrel to the time it strikes the target. There are a lot of factors when dealing with external ballistics, but most notably drag and gravity; drag is what makes the bullet slow down while gravity is pulling it to the earth. For external ballistics the bullet’s behavior can best be hypothesized using projectile motion equations.

Horizontal Distance: X = Vxt      Vertical Distance: Y = Vyot - 1/2(gt^2)   

(Where: Vx is the horizontal velocity, Vy is the vertical velocity,  g is the acceleration due to gravity, t is time taken, and Vo is initial velocity)

There are a vast number of bullet types and calibers that will produce a huge range of data for ballistics. Below is a small chart showing only 30 caliber bullets of different types and weight. The second column shows the bullets expected ballistic coefficient. The ballistic coefficient is basically how well the bullet travels and resists wind and drag effect. A higher ballistic coefficient means the bullet does a better job of bucking the wind. This is just another small example of the many aspects of physics seen in hunting. There is also momentum conservation in the system containing the shooter, the gun, and the bullet as it leaves the barrel.