A type of firearm action where the breech is not locked and the cartridge case expands to seal the breech, using case expansion and pressure to retain gases.

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

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

Select fire is a fire selector mechanism on a firearm that lets the shooter choose the firing mode, such as semi‑automatic, burst, or fully automatic.