Sounds like a Sharps, used in the buffalo hunting days. The percussion version was used in the WBTS. At the battle of Adobe Walls, in Texas in 1874, Bill Dixon hit a Comanche warrior at a measured 1200 yards, almost seven tenths of a mile, with a Sharps. A popular calliber wa .50-110, or .45-110. That's half inch bullet, weighing from 400 to 450 grains, or a .45 inch bullet weighing slightly less. The "110" is one hundred and ten grains of black powder, probably two or three F. The latter refers to the size of each grain. The higher the number the finer the grains. See "Quigley Down Uhder" for his shot at a wate bucket a great distance away. Some of those old boys, using vernier sights (i.e."pop up"), could do some amazing shooting with those old rifles. A company in Montana still makes them. Stan