I recently clocked speeds on my 1861 Navy vs my Remington Navy using equal charges and balls.
Even though the Remington is 1.5" shorter it's giving me 150fps more.
The gap on my Colt is over 0.020". That's my largest shim and it dances around in there.
My arbor has been corrected so it's dead on. I've seen some youtube methods of correcting this which requires filing the barrel by the pins and the arbor at equal amounts. I'm not used to working on these so I'm not sure if it's a sound method or necessary.
Any advise from the experts would be appreciated.