Breech block for a carbine - pivot arm swings up to engage curved recess for automatic fire

摘要

A breech block (1) is pushed into the closed position by rod (20) with a spring (20) around it and with a block (16) attached to the breech block by a pin (17) and with a buffer pad (19) which engages the arming lever (21) above the barrel (3). For automatic fire, when the breech block is forced backwards, a pivot arm (12) which fits inside a recess in the block swings up about a pivot pin (11) so that its cylindrical head (12') engages a curved recess (2') inside the upper surface of the breech housing, thus wedging it to use the gas pressure for maximum firing force. For single rounds, a different block is used to give a positive engaged or released position of the pivot arm (12) for the required braking action.