We only see the pictures of the ones that made it into production. There has to be tens of thousands of firearm concepts that never made it past a prototype.
And there are odd ball designs that no one has ever heard about, one class are the pistols with annular grooved chambers.
The whole concept was to cut annular and/or helical grooves in barrel chambers to permit propellant gases to expand the walls of the fired case into these grooves, thereby causing resistance to extraction or case projection of the bolt.
Their purpose is to slow down the opening of the slide to enable the use of a relatively light slide and recoil spring, thus a lighter firearm. One pistol using this system seems to have been made in quantity: the Chinese Type 77 pistol. https://en.wikipedia.org/wiki/Type_77_pistol This pistol has an annular groove in the chamber. Firing results in a bulge in the cartridge case measuring approximately 8.58-8.59 mm in diameter. The re-sizing of this bulge in the process of extraction slows down the slide.
see what one goes for at auction: https://www.rockislandauction.com/detail/64/3325/rare-chinese-model-77-semiautomatic-pistol
Another pistol the Chinese made with chamber retarding grooves was the Type 64
Are Chinese Type 64 pistols exported? If so, why is it a collectible ammunition in the United States?
In order to overcome these shortcomings, the 64-type has a spiral groove in the chamber, and the 77-type adds a drum-shaped annular groove at the rear of the chamber. The shell is deformed and embedded in the groove under the pressure of the chamber to increase the shell resistance. ,
I can think of more disadvantages to this system than advantages, which is perhaps why there are so few pistol types.
Another weird one from China, the silenced Type 64.
And there are odd ball designs that no one has ever heard about, one class are the pistols with annular grooved chambers.
The whole concept was to cut annular and/or helical grooves in barrel chambers to permit propellant gases to expand the walls of the fired case into these grooves, thereby causing resistance to extraction or case projection of the bolt.
Their purpose is to slow down the opening of the slide to enable the use of a relatively light slide and recoil spring, thus a lighter firearm. One pistol using this system seems to have been made in quantity: the Chinese Type 77 pistol. https://en.wikipedia.org/wiki/Type_77_pistol This pistol has an annular groove in the chamber. Firing results in a bulge in the cartridge case measuring approximately 8.58-8.59 mm in diameter. The re-sizing of this bulge in the process of extraction slows down the slide.
see what one goes for at auction: https://www.rockislandauction.com/detail/64/3325/rare-chinese-model-77-semiautomatic-pistol
Another pistol the Chinese made with chamber retarding grooves was the Type 64
Are Chinese Type 64 pistols exported? If so, why is it a collectible ammunition in the United States?
In order to overcome these shortcomings, the 64-type has a spiral groove in the chamber, and the 77-type adds a drum-shaped annular groove at the rear of the chamber. The shell is deformed and embedded in the groove under the pressure of the chamber to increase the shell resistance. ,
I can think of more disadvantages to this system than advantages, which is perhaps why there are so few pistol types.
Another weird one from China, the silenced Type 64.
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