My latest acquisition. First I will apologize for the pics across my knees and such. I picked this up and am hoping to learn a little more about what I have. Gun is unsigned. I will have to cast the chamber but I am suspicious that it is something along the lines of a 450-577. Top rib is not integral. Leaf sights out to 500. Ladder site will not stand up. I will take more detailed pics of it later. Various proof marks in pics on barrel, breech block, and frame. I think british viewing marks on the block, barrel and frame? Also BP black powder proof on barrel? And a little difficult but 450- Refers to Bore? It was just too cool to pass up.