Breech action

1.The breech mechanism in breech-loading small arms and certain special guns, as automatic and machine guns; - used frequently in referring to the method by which the movable barrels of breech-loading shotguns are locked, unlocked, or rotated to loading position.
References in periodicals archive ?
The SIG 238, which is currently available, uses a locked breech action and is a little gem.
The semiautomatic TP-9 has an interesting recoil operated, rotating barrel, locked breech action that is machined on state-of-the-art CNC equipment from 4140 steel.
A wedge-lock, breech action design provides fast, safe and trouble-free opening and closing of the doors.
The company's vulcanizer is designed for processing robber hose at 150 psig and 400 [degrees] F, measures 72" in diameter x 20' in length and features a mechanism for wheel-less external cart-loading, a vertical lift door and the Rapidoor wedge-lock, breech action access door for fast, trouble-free material transfer, according to the manufacturer.
Typical of most modern semi-auto pistols, the S&W 5900 series employ a locked breech action that uses the Browning cam-operated tilting barrel system to lock and unlock the action at the moment of firing.