I've been shooting cast in a P-229 Sig in 40 S&W for the past ten years. Using a LBT WFN 185 grain mold. Mostly water dropped straight wheelweights, LBT Blue lube, no problems at all.
I also firelapped the barrel using one of Veral Smith's firelap kits. I did have a bit of leading on the lands prior to firelapping but none that didn't come out easy using a shreds from a copper chore girl pot scrubber wrapped around an undersized brass bore brush.