Meet the AA12, the world's first (and scariest) automatic shotgun, built by Jerry Baber of MPS.
From Discovery Channel's FutureWeapons:
It's a gun that could end up rewriting the rules of urban warfare. I'd like to introduce you to the shotgun for the 21st century, the AA 12. The Auto Assault 12 is a fully automatic, gas operated, low recoil, 12 gauge shotgun designed specifically for the military. One blast from the shotgun is terrifying enough, but the AA12 delivers an incredible rate of nearly 300 rounds a minute.
Hit play or go to Link [YouTube] - Thanks Adam Fuhrer!