Jamison brass rim

[ken s]

I shoot an original Sharps 1874 Sporting rifle, 40 70 SS
I had the chamber sleeved, but the barrel is the original with all the shallow rifling.
Gun is in great condition.

I think the Jamison brass, which works, but is tight on closing, has a thick rim.

The rim of the Jamison is .65 or even a little larger.
The rim listed for the Original is .50. I had mine cut to the original with a custom RD cutter.

SO. While the eject, they have to be 'popped' out. with the lever.
I clean each shot, and chamber wipe too. No fouling.
I use 2F OE and 57 to 62 grains with a 330 Brooks custom duplicating the original RN bullet. 4 inches at 100 yards. still working out loads.
QUESTION. CAN I HAVE BRASS MADE WITH A .50 RIM? IF NOT,ANY THOUGHTS ON HOW TO TRIM? Ken