Atchisson Assault Shotgun(AA-12) model picture

Atchisson Assault Shotgun:

the Auto Assault-12 (AA-12), originally designed and known as the Atchisson Assault Shotgun, is a shotgun developed in 1972 by Maxwell Atchisson. The current 2005 version has been developed over 18 years since the patent was sold to Military Police Systems, Inc. The original design was the basis of several later weapons, including the USAS-12 combat shotgun. The weapon is selective fire, operating as a semi-automatic, or in fully automatic mode at 300 rounds per minute. It is fed from either an 8-shell box magazine, or a 20- or 32-shell drum magazine. In 1987, Max Atchisson sold the rights of AA-12 to Jerry Baber of Military Police Systems, Inc., Piney Flats, Tennessee.

MPS in turn developed the successor simply known as Auto Assault-12, which was redesigned over a period of 18 years with 188 changes and improvements to the original blueprint. MPS also teamed up with Action Manufacturing Company, and Special Cartridge Company to combine the gun with FRAG-12 High-Explosive ammunition into a multifunction weapon system.

The weapon was lightened to 4.76 kg and shortened to 966 mm but retained the same barrel length. The CQB model has a 13-inch barrel, and is half a pound lighter than the regular model. Uncommon in other automatic shotguns, the AA-12 fires from an open bolt, a feature more commonly found in submachine guns and heavy and squad level machine guns.

It uses 8-round box, 20-round drum, or 32-round drum magazines, as opposed to the original 5-round box magazine. Due to the abundant use of stainless steel and the designed clearance for fouling, MPS has claimed that the weapon requires zero cleaning or lubrication. The designer states that cleaning is required after 10,000 rounds.

Some Atchisson Assault Shotgun Picture below :