breechblock

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breechblock

[′brēch‚bläk]
(ordnance)
A movable steel block in the mechanism of a breech-loading gun that seals the breech opening of the barrel during firing.
References in periodicals archive ?
These mate with the rear of the breech block when firing the rifle and lock the block shut.
The number is actually on the flat surface on top of the breech block lug, near where the hinge pin is located.
With the breech block in the locked position, the primer is protected from rain and snow, and the design also permits easy access to the primer pocket.
The breech block is part of the M119A2's cannon assembly, along with the muzzle brake, cannon tube and breech.
I am a new gunsmith and I have a old Browning Auto-5 (serial number 46808) with a locked up breech block and I can't get the barrel off.
The firing-pin and firing-pin spring were retained by the screw-in bushing and the bushing was pinned into the breech block to keep it from turning out.
The severe taper of the case insures easy extraction plus the rear of the 2-piece breech block is springloaded and pushes forward on the base of the tapered case as the action is opened.
Change all coax ammo feed chute references in Step 4 to breech block.
Limited Tenders are invited for Carrier Breech Block (Icr1268)
The SD9 had a flame and slide of formed sheet steel, with the barrel and breech block nicely machined from bar stock.