Barrel

The barrel is a metal tube through which the projectile travels.

Bore

The interior of the barrel. The bore may be smooth or rifled.

Breech

The rear end of the barrel, closed by a part called the breech plug. There are three types of breech plugs:

• Flint
• Bolster
• Nipple

Muzzle

The open end of the barrel, where the projectile leaves the gun. In a muzzleloading firearm, the powder charge and projectile are loaded into the muzzle.