Chapter 3: Know Your Firearm Equipment
What Is Ammunition?

Modern ammunition varies depending on the type of firearm. Rifles and handguns use a cartridge containing a single projectile (bullet). Shotguns use a shotshell containing either a single slug or a large number of small projectiles (shot or pellets). However, the basic parts of cartridges and shotshells are very similar.

Basic Parts of Ammunition

The basic parts are the case, primer, powder, and projectile(s). Shotshells have an additional part called a wad.

• Case: The container that holds all the other ammunition parts together. It's usually made of brass, steel, copper, paper, or plastic.
• Primer: An explosive chemical compound that ignites the gunpowder when struck by a firing pin. Primer may be placed either in the rim of the case (rimfire) or in the center of the base of the case (centerfire).
• Gunpowder: A chemical mixture that burns rapidly and changes to an expanding gas when ignited. Modern smokeless powder will burn slowly when ignited in the open (outside of the case). Black powder is less stable and can be explosive when impacted or ignited in the open.
• Projectile: The object(s) expelled from the barrel. A bullet is a projectile, usually containing lead, fired through a rifle or handgun barrel. A slug is a solid projectile, usually of lead, fired through a shotgun barrel. Shot is a group of lead, steel, tungsten alloy, or bismuth pellets fired through a shotgun barrel.
• Wad: A seal and/or shot container made of paper or plastic separating the powder from the slug or shot in a shotshell. The wad prevents gas from escaping through the shot and holds the shot together as it passes through the barrel.