I've never heard of a powder burning so hot as to melt the base of a cast boolit before especially in a pistol length barrel. I have seen leading in barrels where size of the boolit caused leading. I fought this battle with a 9mm M&P Pro, I bought 3 different sizing dies to get it right. Too small and too large caused the gun to lead, once I hit the size the gun wanted, no more leading.
wcp