Cartridge is a metal or paper case that holds a charge of explosive powder and a bullet or a charge of shot. The cartridge used in rifles and machine guns is a metal cylinder with a percussion cap at the base. The explosive is placed in the cartridge and the bullet is placed on top of it. The metal is crimped (pressed) against the bullet to hold it firmly in place. When the gun is fired, the charge ignites and the resulting explosion propels the bullet down the barrel.
Cartridges for shotguns usually consist of several thicknesses of stout paper with a brass base to give additional strength and to hold the percussion cap. A blank cartridge contains a charge of explosive, but no ball or shot. Cartridges made of paper were first used in muskets in 1585.
