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.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
The two Model 1870 Trapdoors pictured here are typical of the model with one notable exception--one is a standard Model 1870 rifle and the other known as the "Cadet" is a scaled-down Model 1869 (although correctly it carries an 1870 marked breechblock and a full-size .50-70 chamber).
In addition, the Uberti's Grade A walnut stock is much more attractive, and with its deep bluing and case-hardened breechblock, the overall gun is strikingly handsome, in part due to not having gone through numerous battlefield skirmishes.
To load, put the hammer on half-cock, flip open the Trapdoor's reverse-hinged breechblock all the way back until you hear the click of the ejector and insert a cartridge, always keeping the muzzle pointed downrange.
At the rearmost point of movement, the breechblock was held to the rear while the barrel, powered now by the compressed recoil spring, was pushed forward and back into the original position.
The better of the two, the one I bought from my buddy, had a broken breechblock. It also had a broken link.
The gun store junker also had a broken breechblock. This was a fairly common problem with these early guns.
Jeanne Brooks, a mechanical engineer with Benet Laboratories, said arsenal and Benet Lab engineers supported and monitored user feedback on the cannon for more than 10 years in search of ways to perfect the breechblock both for functionality and for producibility.