Ballistol?

[Griff]

Based on my experience with black powder in my .45 Colt, the bore can become fouled after just one stage.

The bore being fouled is immaterial as long as your bullet carries enough lube to keep it soft; the next shot will wipe it
out  Changing to a .44-40 will not affect bore fouling.  The .44-40does a much better job of keeping fouling from the action, however annealing 45 Colt cases does a stellar job also.  I just thinned my carrier in my '73s and Henry so buildup of fouling in the carrier mortise doesn't hinder smooth operation for even a 3-day, 12 stage match.  Rugers seem to need a bit more cylinder/barrel gap than do Colts or most clones due in part, to cylinder bushing design.  But just with bullet lube, the lube for the gun needs to be of type compatible with BP.