Basic Components of Rifle Cartridges

The basic components of rifle ammunition are the case, primer, powder, and projectile.

Glossary

case: The container that holds all the other ammunition components together. It’s usually made of brass, steel, or copper.
gunpowder: A chemical mixture that burns rapidly and converts 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.
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).
projectile: The object(s) expelled from the barrel. A bullet is a projectile, usually containing lead, fired through a rifle.