I use CFE in .38 special, and .45 ACP. Target shooting only with either lead of plated bullets. At minimum charges, there is actually soot that comes out of the barrel. I find these little soot flakes the size of a match head on my rug on the shooting bench. like a acetylene torch with no oxygen. Maybe that's what keeps copper from fouling? Not a mess, but strange for sure, No unburned powder, just soot. One hole 20 shot groups at 30 ft. though off a rest.