A bayonet lug is a metal fitting on the barrel or muzzle of a firearm that provides a mounting point for a bayonet.

A cylindrical ammunition container, typically mounted on a firearm, that holds cartridges in a spiral arrangement for feeding into the chamber.

Firearm action type where expanding gas from a fired cartridge cycles the mechanism, typically via a piston or direct impingement.

Uses high-pressure gas to cycle the action, rather than recoil energy.

Integral bipod: a permanently attached, built‑in bipod that provides a two‑point support for a firearm, allowing it to be rested on a surface without separate accessories.

Adjustable metal aiming devices on firearms, consisting of a front post and rear notch, used without magnification.

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