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 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. It is designed to fire three different types of 3' 12 gauge shells: Buckshot, slug, or Frag-12 rounds. Due to the abundant use of stainless steel and the loose manufacturing allowed in a shotgun, MPS has claimed that the weapon requires zero cleaning or lubrication. The designer states that cleaning is required after 10,000 rounds.