My first made to order rifle was a C. Sharps Arms Model 1885 in 40/50 I ordered in 2009. I have been loading for it, cussing it, putting it away, getting it out again, since then. Never could get it to shoot smokeless, black, synthetic or any other powders with bullets from 265 to 400 grains. Since I was heavy into Military Rifle CBA benchrest matches, I only got to play with this rifle a couple of months in the fall after benchrest season. Today I got my first sub-MOA ten shot group with a KT-6 Weaver scope.
The break threw came when I talked to a friend of the designer for the reamers; all of the .40's were made to shoot paper patched pure lead bullets with black powder. Even though I thought I had the bullet seated far enough out of the case, it was just in a section with the lands removed. By doing a chamber cast I found out It needs to be seated another 3/8" forward, just short of the lands.