Elephant Powider has been a very "dirty " with excess fouling. It is possible the powder is the problem. It is telling that other black powder worked better.
The powder WAS the problem.The Colt SAA I just mentioned fouled within 24 shots and was hard to recock.
Our son,Rob,Tom Schiffer and myself shot 100 rounds with GOEX 3fg,35 grains per case and the old style
bullet Lyman 454191 buttered with a home made lube and the gun got so hot the metal parts were untouchable
but we had no problem with consecutive shots.This was in the early 1990's at Ralph Marcum's Hooten Old Town
shoot for buffalo guns and period revolvers.There IS a difference in powders.
Bob Roller