My Sharps likes a crimp in the 457124 or 457125 cast bullets with BP loads. I tried it both ways.
I crimp the Model 1894 .30-30 and the 1892 Rossi .44 Mag (I shoot nothing but BP loads in the .44 mag rifle)
I never crimp for Bolt action, M1 Garand or AR-15, bottleneck ctgs don't seem to need it.
Always crimp revolver loads, especially if they are heavy loads. You will end up with a bullet backing out of the ctg and tie up the cylinder.