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.
Centurion Arms CMR upper with Mega Arms lower, Magpul, Trijicon ACOG, offset is from Vortex Optics. The light is a SureFire the blades are Gerber Gear. Photo by Stickman. I like the axe and am going to use it as an inspiration from a circular saw blade.