What is the C.O.L. for the 45-90? One search said 2.88 inches but I am unable to confirm.
You will see it quoted between 2.80-2.88”. In some conversions, smiths recommend 2.75”. I would start by loading one cartridge at 2.80” and see how that cycles in your rifle. You can see what the loaded cartridge needs to clear as the cartridge clears the mag. This is easy to follow in a top eject levergun. A stuck shell will likely mean magazine disassembly and is something to be avoided.
