[Disambiguator]

They mention a shotgun with a 17” barrel. If you go buy a Mossberg 500, for example, the shortest barrel you can put on it is 18.5”. I’ve seen plenty of these with pistol grips on them, but they don’t have 17” barrels.

Where are these 17” barreled shotguns?

[optiguy]

http://www.mississippiautoarms.com/tromix-converted-saiga-12-s17-short-barrel-shotgun-p-1261.html

[Bloody Sam Roberts]

Exactly. In my state, a shotgun with a barrel shorter than 18” is strictly verboten.