I see there is a question or two so I'll back up the truck
This is a 1862 type 1 Gatling's Battery Gun, Gatling gun for short.
The type 2 used the same cylinders chambered for 58 cal.copper cartridge.
The metal finish is not done. the frame is to be blued, barrels plum brown, and breech, front and rear barrels plates and front sight bridge bronzed.