Ammunition Parts

The assembled package of the casing, the bullet, the propellent (typically gunpowder), and the primer.
Bullet
The projectile expelled from the firearm.
Casing
The metalic case in which the primer, gunpowder, and bullet are package.
Gunpowder
The explosive powder that acts as the propelant for the bullet.
Primer
The small, circular button at the base of the ammunition casing, filled with nitro glycerin, when struck, explodes.