Ballistics: the basics

Many People ask me about ballistics and most of those questions are the simple one’s, e.g., how is a bullet fired from a firearm? So I thought I’d tell you all the answer. First i’ll start off by telling you that some bullets may be different in shape, size, and weight but the are all constructed generally the same. A bullet has five main parts the bullet itself, the bullet casing, the propellent, the rim, and the primer. Here’s an overview of how a bullet is fired, when the firing pin of the firearm hits the primer it makes a tiny explosion that ignites the propellent (gun powder) inside the bullet casing thus propelling the bullet  out of the barrel of the firearm.
Bullets can be matched to other bullets found at a crime scene or test fired at a crime lab, by looking trough a microscope at the fired bullets side by side you can see very fine striations left on the bullet when it was propelled out of the firearm, these striations are unique just like a fingerprint is and can be matched to one and other. Another way of matching bullet is by looking at the shell casing, provided you have the shell casing of course, and looking a the primer of a test fired bullet casing and one found at a crime scene if they are a match the area on the primer where the firing pin hit they will be the same and again these are unique.

- Brandon Anderson