The four main types of modern firearms today are bolt-operated, pump action, semi-automatic, and automatic weapons. In a bolt-action weapon, each new [[round (ordnance)|round]] must be loaded manually, by moving the [[breech]] to eject the empty casing. In pump action guns (usually shotguns) a new round must be manually loaded by pulling back on pump of the gun, located underneath the barrel. | The four main types of modern firearms today are bolt-operated, pump action, semi-automatic, and automatic weapons. In a bolt-action weapon, each new [[round (ordnance)|round]] must be loaded manually, by moving the [[breech]] to eject the empty casing. In pump action guns (usually shotguns) a new round must be manually loaded by pulling back on pump of the gun, located underneath the barrel. |