Your handgun is commonly known as a swivel breech derringer.
The American Arms Co. made a handgun that looks just like yours, but it is a cartridge handgun, not a muzzleloader.
The American Arms Co. was located in Boston, Mass. and made swivel breech, double barrel pocket pistols from approx. 1866 to 1878.
They made them in several different calibers.
.22 rimfire in one barrel and .32 rimfire in the other.
.22 rimfire in both
.32 rimfire in both.
.41 rimfire in both
If yours is a muzzleloader, then the above info would not apply.
The American Arms Co. made a handgun that looks just like yours, but it is a cartridge handgun, not a muzzleloader.
The American Arms Co. was located in Boston, Mass. and made swivel breech, double barrel pocket pistols from approx. 1866 to 1878.
They made them in several different calibers.
.22 rimfire in one barrel and .32 rimfire in the other.
.22 rimfire in both
.32 rimfire in both.
.41 rimfire in both
If yours is a muzzleloader, then the above info would not apply.