serbu super-shorty

The Super-Shorty is a compact shotgun manufactured in the US by Serbu Firearms. It is essentially a conventional pump-action shotgun with no shoulder stock and an extremely short (usually 6½ inches) barrel, hence the name. Since the tubular magazine of such a shotgun can be no longer than the barrel, this modification also sharply limits the weapon's magazine capacity to only two rounds (as opposed to the five to seven typical of full-length pump-action shotguns).

As a smoothbore handgun, the Super-Shorty is classified as "Any Other Weapon" under the US National Firearms Act of 1934, meaning civilian transfers of ownership in the United States require the purchase of a $5 federal tax stamp and registration with the Bureau of Alcohol, Tobacco, Firearms and Explosives.

wikipedia: Serbu Super-Shorty