AA-12 Atchisson Assault Shotgun
Summary
| Country | 🇺🇸 United States |
| Category | Combat shotgun |
| Manufacturer | Military Police Systems, Inc. |
Technical specifications
| AA-12 Atchisson Assault Shotgun | |
|---|---|
| Fire Rate | 32 rounds/min. |
| Caliber | 12 (19.5 x 76 mm) |
| Magazine | drum of 20 - 32 rounds |
| Length | 991 mm (39.0 in) |
| Weight | 7.3 kg (16.1 lb) |
| Range | 50 m (164 ft) |
Description
The AA-12, originally known as the Atchisson Assault Shotgun, was initially designed by Maxwell Atchisson in 1972. This early development appears to have resulted in only a limited number of prototype firearms. In 1987, Max Atchisson sold the rights to Jerry Baber of Military Police Systems, Inc. (MPS). MPS undertook a significant redesign over a period of 19 years, incorporating 188 changes and improvements to the original concept, resulting in the version designated as the Auto Assault-12.
The MPS redesign changed the mechanism from blowback to a gas-operated system with a locked breech. This proprietary gas system is designed to absorb a significant portion of the felt recoil. A recoil spring further reduces recoil forces. The weapon was lightened to 4.76 kg and shortened to 966 mm compared to the original design, though the barrel length remained the same. It operates from an open bolt, a feature less common in automatic shotguns but seen in other automatic weapon types. The AA-12 fires various 12-gauge ammunition types, including buckshot and slugs. It is fed from either an 8-round box magazine or a 20-round drum magazine, an increase from the original 5-round box capacity. Constructed with extensive use of stainless steel and featuring designed clearance for fouling, MPS indicates the weapon requires minimal cleaning or lubrication. A rail system is available to facilitate modern sighting options.
A CQB model of the AA-12 is also noted. This variant features a shorter 330 mm barrel and is approximately 0.2 kg lighter than the standard model.
By 2004, ten functional models of the AA-12 had been produced and were demonstrated to the United States Marine Corps, but the service did not adopt the weapon. The weapon was proposed for integration into unmanned systems, such as the dual-mounted Hammer unmanned defense system by More Industries on the H2X-40 turret, and Neural Robotics considered mounting it on their AutoCopter unmanned aerial vehicle.