breechblock
Breech"block, n. Defn: The movable piece which closes the breech of a breech-loading firearm, and resists the backward force of the discharge. It is withdrawn for the insertion of a cartridge, and closed again before the gun is fired.
Breech"block, n. Defn: The movable piece which closes the breech of a breech-loading firearm, and resists the backward force of the discharge. It is withdrawn for the insertion of a cartridge, and closed again before the gun is fired.