There’s more to ammo than just the bullet. What we colloquially refer to as a ‘round of ammo’ is known as a cartridge.

A cartridge has four main components:

Bullet: The projectile that travels through the gun’s barrel and is ejected through the muzzle of the gun.

Case: The container that holds the powder charge.

Powder Charge: The powder that violently releases a large amount of gas when it catches fire.

Primer: A small amount of chemical that creates a spark when it experiences an impact.

A Cartridge. ¹

The way a gun ‘shoots’ a bullet is as follows:

1. A cartridge is seated in a chamber - a cavity that opens to the barrel of the gun
2. Something (a hammer or firing pin) strikes the primer on the cartridge
3. The primer creates a spark
4. The spark ignites the powder charge
5. The powder charge violently releases a large amount of gas
6. The expanding gas propels the bullet through the barrel and out the muzzle

There are two main kinds of cartridges used in handguns: Rimfire and Center-fire cartridges. In a rimfire cartridge the priming compound is located along the rim of the base of the cartridge. In a center-fire cartridge, the primer is located in the center of the base of the cartridge. The picture above shows a center-fire cartridge.

Continue reading: How Handguns Work