I saw that picture on QI. Fuckin punt guns. I think they were for vaporizing entire flocks of ducks.
I like the KS-23.

Some of you probably already know, but "23" doesn't refer to gauge or caliber. It's the barrels measurement in millimeters. These shotguns are made from discarded 23MM anti-aircraft gun barrels. The civilian version is the TOZ-123 and all versions were made illegal for sale in the united states by the Clinton administration.