Atchisson AA-12

The AA-12 (Auto Assault-12), originally the Atchisson Assault Shotgun, is an automatic combat shotgun chambered in 12 gauge that Maxwell Atchisson designed in 1972 with a focus on reduced recoil, though only prototypes were built under Atchisson's own development. Military Police Systems, Inc. later acquired the design and, in 2005, released a substantially reworked version using a proprietary gas-operated system the manufacturer states absorbs around 80 percent of the recoil a shooter would otherwise feel. The weapon is best known through this MPS-developed automatic configuration rather than the original 1972 prototypes.