What is a Shell Casing?
A shell casing is a piece of ammunition that is made of metal. It is often brass, but it can be made of other metals as well.
Shell casings can be made from any kind of ammunition that is fired from a pistol, rifle or shotgun. It is not a bullet but it is a piece of the larger ammunition mechanism that is loaded into the chamber to be shot.
To understand the role of a shell casing, it is better to understand the way that a gun works and its purpose in firing.
How a Gun Works
A gun is an instrument to fire bullets, but much of the explosion actually comes from the bullet.
A bullet, on the other hand, is like a miniature firework that is rigged to explode. It comes in three pieces- the primer, the propellant, and the proper part of the bullet. These sections are housed inside a brass jacket called a shell casing.
The gun works by hammering a tiny pin into the end of the ammunition and igniting the primer, which is a small explosive charge. The spark ignites the propellant. It’s like a tiny version of setting a match to gasoline which causes a much bigger fire or explosion.
The casing is designed to force the explosion to go only one direction and that is forward and out the barrel of the gun. The casing surrounds the entire bullet area. It’s usually hollow inside to make room for the propellant liquid or gas. The end of it is flat with a small dimple or indentation that makes room for the pin to strike the primer as directly as possible.
The casing is thickest on this strike plate to protect the person firing, so that things only explode away from the shooter and not toward them.
To give you a better idea on how guns work, here’s a video you can watch:
Finding Shell Casings
Shell casings are often found at the sites of places where guns were fired. They are expelled from a gun, usually when a new bullet is loaded into the chamber to be fired.
When crime scenes or hunting areas are searched after bullets or shot has been fired, casings are a common remnant in the area. With bullets, the casings are entirely metal and usually reasonably small.
Shot casings, meanwhile, are larger. They come with a brass strike plate on the bottom and a plastic sleeve that held the shot attached to it.