Here you can see the top, the in German called "Königs-Disziplin" (in english: King Style), the "German Vierling", an gun with four barrels.

Two for the shootgun (12/70, 16/70, pp) and two for the bullets (normaly a smaller and a bigger caliber).

Very difficult to build, but it works great.
Like every Heym, they can be for an collector, but it still can be used in an hard hunt.
In the USA, Oversee, Europe or Africa of course.