A type of semi-automatic pistol action where the barrel remains locked for a short period after firing, delaying the blowback of gases to slow the opening of the breech.

A firearm feed system where ammunition is stored in a separate container (magazine) that can be removed and replaced, enabling rapid reloading.

A mounting system for attaching optical sights to rifles.

A pistol barrel with external helical grooves allowing the attachment of a suppressor or other muzzle devices.