Works for me!
I know this will sound strange, but lately I've been cleaning my jacketed bullets with rubbing alcohol prior to putting them in the sabot. Sometimes they come from the factory kinda dirty.
Since starting this, and with no other load changes, my group size had improved measurably. My .50 caliber Firehawk has been giving inch or less groups at 100 yards with increasing regularity and 10 shot total groups ( I shoot 3 shot groups, 10 rounds total) are right around 2 inches. This with 45 caliber XTP's of 230, 250 and 300 grains. Usually 1 group is inch or less , sometimes 2 but I have had occasions when all 3 were inch or less. Best so far was a 7/16ths with a 230 grain.
Aperture sights btw.
Give it a try. Maybe it'll work for you too!