I did the same last week. I found the sleeved sabots too tight, and shot erratically on the range. I switched to powerbelt aero tips and they were a little easier to feed down the barrel, and accuracy improved dramatically.
I had this same muzzleloader and used a Hornady 240gr .44 XTP in a sabot on top of 90grs of granular Pyrodex R/S. Loading became difficult around the 3rd or 4th shot. Accuracy suffered as well. I pulled the breech plug and swabbed the barrel from breech to muzzle with T/C cleaner and everything returned to the way way it was.