breech bolt

breech bolt

[′brēch ‚bōlt]
(ordnance)
A mechanism which opens and closes the breech in a carbine, machine gun, rifle, and the like; designed to push a cartridge into the chamber by sliding action.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
Then push in the breech release button and lift up the rear of the breech and breech bolt as an assembly and withdraw to the rear, setting it aside.
Closing the finger lever elevates the locking bolt at the rear of the receiver into engagement with a deep slot on the underside of the breech bolt.
Drop the hammer, remove the rear sight, re-cock the hammer and slide the breech bolt from the receiver.
As the employee turned the handle on the breech bolt, it was expelled into his leg by the gas.
As the employee turned the handle on the breech bolt holding the round, it was forced out at high speed by the trapped gas.
When the breech bolt is moved, the gun will jam with the bolt to the rear.
When a Benelli is fired, the mass of the breech bolt remains stationary while a carefully calibrated spring pushes against the rotating bolt head, forcing it into tighter engagement with its matching cuts in the barrel extension.
"When the action-bar sleeve impacts against the front of the receiver, 5 ft-lbs of the 10 ft-lbs stored in the moving mass are put back into the equation and an instant later the breech bolt, still moving rearward, impacts against the rear section of the receiver, putting back the other 5 ft-lbs, thus satisfying Newton's Law."
Upon inspection, he determined that a GAU-8 Breech bolt firing pin had failed causing every seventh round not to fire.
If you are dealing with a semi-auto or lever gun where you cannot easily remove the breech bolt to look through the bore, you can use a collimator to get the bore and crosshair intersection aligned as closely as you are able.