Show a shot or two of the other side. It might have the maker's name on it. I'm also curious how it reloads since there is no cylinder release on the left side of the frame of a bar under the barrel.
I'm guessing it dates from about the late 1800s, not long after the civil war.
Can it be from another country, maybe England? Just guessing here.
Found this one online also. It is listed as the H&R American, Double Action. The gun is obviously different but the grips look the same to me. Th OP's gun with unfluted cylinder and round barrel must be the Lew Horton or Talo version