More ideas from robin

This is an antique, German combination gun (according to the OP) that appears to have several gauges of ammo, like a rifle, shotgun, and pistol bullets. The flourish designs on the gun are beautiful as well.

Smith & Wesson Unveils "Backpack Cannon" - .460-caliber revolver. (Sidearm while fishing in Alaska)

KitUp's headline for the new Smith & Wesson revolver is "Smith & Wesson Unveils Backpack Cannon." Judging by its size, it looks like a hand cannon to me, yes. Or like a power tool that can kill you.