Breechblock

[bri:tʃblɒk]

Definition

(noun.) a metal block in breech-loading firearms that is withdrawn to insert a cartridge and replaced to close the breech before firing.

Checked by Amy--From WordNet

Definition

(n.) 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 It is withdrawn for the insertion of a cartridge, and closed again before the gun is fired.

Typed by Carlyle