It it was likely originally a 8 bore brass case gun chambered for at least a 3&1/8" cartridge. None of my books show an example of a 6 bore cartridge gun. It may very well have been a smooth bore ball gun, the 36" tubes would be very long for a rifle. The bolted safeties look original to the gun.

Do we know the actual weight of the rifle? I believe 29 pnds is incorrect.

Steve