There were two types of Sharps cartridges with the same powder charges. One type had a straight tapered case, and the other type had a bottleneck case. I think they were both available at the same time. Remington produced guns in the same calibers, but designated them differently. I have a Remington Hepburn rifle in .40-50 Sharps straight, but it is marked .40 1 7/8. I have worked up loads with this rifle using Hodgdon 322 powder and paper patch bullets that approximate a hot .38-55 load. One grain too much powder, and the action locks up due to the primer extruding into the firing pin hole. I also have a barrel insert in .40-50 Sharps bottle neck, but have never developed any loads for it, and if I ever do, I expect that I will run into the same problem with primer extrusion that I had with the rifle, and maybe at even lower pressure because of the large firing pin and hole. I prefer using a slower powder than 4198 because of the sharper rise in pressure with small increases in charge with 4198, so I use something like 3031 or H322.
