My handgun lube is a mix of toilet ring wax, parrafin, and STP oil treatment (with a red crayon in it for color). I don't get any leading out of my .38, but I have to admit it's smoky. For an outdoor lube, it's been working fine for me. Granted a middle of the road .38 special isn't the most demanding application.

From what I understand, back in the day toilet seals were made out of bees wax, but today they are made mostly of some kind of silicone based stuff (the package I used said "contains bees wax" which implies it's not 100%).