The AA-12 Automatic Shotgun

In 1972, Maxwell Atchisson designed and patented a shotgun that fired shotshells at rate of 300 per minute. Atchisson’s design could be equipped to fire 12 gauge shells from five-round and eight-round box magazines or 20-round and 32-round drum magazines.

The awkward-looking design relies heavily on polymer construction with a streamlined, unadorned frame that, in my opinion, looks more like it belongs on a gun of bullpup configuration – except that it isn’t. The magazines feed from directly in front of the pistol grip and trigger. It also fires from an open bolt, like squad machine guns – a feature unusual in automatic shotguns.

Atchisson’s original design was not without flaws: fouling caused by the plastic shotshell material caused the gun’s polymer components to gum. Because of this, it proved to be less than reliable.

In 1987, Atchisson sold the design to Tennessee-based Military Police Systems, Inc. There, the gun underwent a design overhaul. It was lightened by a pound, going from 11.5 to 10.5 pounds, and shortened, from 39 inches to 38 inches.

When the gun was designed, one of its main benefits was that it reduced felt recoil. This aspect of the AA-12 was kept and improved upon as well. It went from being blowback-operated to gas-operated with a fixed bolt. A total of 80% of the recoil is utilized by the gas system and another 10% is absorbed by a recoil spring, leaving the user to feel only 10% of the recoil compared to a normal 12 gauge shotgun.

MPS also fixed the fouling issues by incorporating stainless steel components inside the gun. As such, they claim the gun only requires cleaning and lubrication every 10,000 rounds.

In 2004, the United States Marine Corps witnessed a demonstration of the AA-12. In 2006, Neural Robotics and More Industries upped the ante with the AA-12’s capabilities. More Industries mounted the gun on a remote-controlled turret that could be attached to manned and unmanned military vehicles. Neural Robotics mounted it to their AutoCopter drone.

BC Engineering, also based in Tennessee, has built a semi-auto version of the AA-12, calling it the BC Jaeger. In May 2016, BC announced that the company was interested in selling the rights to manufacture their shotgun.

The entire AA-12 concept – from design to production – has been acquired by Sol Invictus Arms from BC Engineering, who had been shopping it around since 2016. They moved all of the tooling, etc from Tennessee to Florida and jumped headlong into bringing the fabled design to market.

Featured in more than a dozen video games and countless TV shows and movies, the AA-12 is a gun that’s hard to forget once you’ve seen it. Slightly peculiar in design, the original AA-12 from 1987 was a full-auto offering. While that concept has been retained, Sol Invictus Arms has also developed a semi-auto version.

The full-auto model at Industry Day at the Range was a beast. Loaded with 20 rounds in the drum mag, the gun ate up the 12 gauge shells in short order, firing from an open bolt and spraying the empty shells all around those watching.

Despite the gun’s size, it’s very easy to handle. Doing a full mag dump was no problem.

The AA-12 is projected to cost less than 25% of what the “newer” production guns from the early 2000s were costing, making it much more desirable.

Check out the video of yours truly putting the AA-12 through its paces at the 2019 SHOT Show Industry Day at the Range, which has been filmed in "slo-mo" at the beginning to show how it operates:

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