Atchisson AA-12

Atchisson AA-12
AA-12 automatic combat shotgun
TypeAutomatic combat shotgun
Place of originUnited States
Production history
DesignerMaxwell Atchisson (1930–2003); further developed by Military Police Systems, Inc.
DesignedOriginal design: 1972
MPS design: 2005
ManufacturerMaxwell Atchisson
Specifications
Mass5.2 kg (11 lb) less magazine. 7.3 kg (16 lb) with loaded 32-round drum (original version)
Length991 mm (39.0 in) (Atchisson Assault Shotgun, 1972)
966 mm (38.0 in) (AA-12, 2006)
Barrel length457 mm (18.0 in)

Cartridge12 gauge
ActionAPI blowback (1972 design) Gas-operated (2005 design)
Rate of fire300 rounds/min
Muzzle velocity350 m/s (1,100 ft/s)
Effective firing range100 m (110 yd) (12 gauge slug)
Maximum firing range200 m (220 yd) (FRAG-12 ammunition)
Feed system8 rounds in box magazine, 20 in drum magazine
SightsIron sight, 2× zoom optical scope

The AA-12 (Auto Assault - 12), originally designed and known as the Atchisson Assault Shotgun, is a fully automatic combat shotgun developed in 1972 by Maxwell Atchisson. However, the original development by Atchisson seems to have produced only a few guns at prototype-level, with the development that ultimately led to the gun entering the market being done later by Military Police Systems, Inc. The most prominent feature is reduced recoil. The 2005 version was developed 19 years after the patent was sold to Military Police Systems, Inc. The original design later led to the development of several comparable firearms of such utility, including the USAS-12 combat shotgun. The shotgun utilizes fully automatic blowback action as its primary and only mode of fire. However, the relatively low cyclic rate of fire of around 300 rounds per minute enables the shooter to fire individual rounds through the use of short trigger pulls. It is fed from either an 8-round box magazine or 20-round drum magazine. The charging handle is located at the top of the gun and does not reciprocate during firing.