Probably ok, if you keep the balls in a dust and dirt proof container til use, as I've used tumble lube with 9mm and 45acp cast bullets and if placed in pockets on warm days they become quite lumpy and I've taken to bringing a rag to the range to wipe off bullets that have attracted extra. it tends to act like gum in less than sterile environments, and b/p is about as unsterile as it gets.