[Roundsworth]

The '10A' brass shell has the same outside diameter as the modern paper hull. My 1879 Lifter has very little difference between the chamber diameter and bore diameter, due to the thin 'A' brass shell. The '10B' brass shell is smaller in outside diameter than the 'A' brass and paper hulls. I have dozens of brass shells in my collection. I will put together some photos to show the differences. Basically, the 'A' chamber will take W.R.A. Co. 10 gauge brass, E. Remington 10 gauge brass, UMC 10A brass, REM-UMC 10 brass and paper hulls (old and new). The 'B' chamber will only handle the '10B' brass shell. You are correct in regards to the wad sizes, Forrest. Manufacturers of reloading components carried wads in numerous sizes to accomodate different bores. My 1879 Lifter has '10A' chambers with bores of .808". A thin walled brass shell with 9 gauge wads would be perfect in my gun.