I have been using wheel weights for probably 20 years now. I know they are not pure and not as soft as pure lead however I figured with a patch between the bore and the ball no harm would be done. I can still scratch the lead with my finger nail. My accuracy is fine and I have a few deer under my belt with them. No problems. My old supply has finally run out and I had to get some new ones. I got some from two different sources and noticed not all the weights are melting. They just sit there in the pot. I am guessing maybe 10 percent won't melt. I also noticed that the un meltables have very sharp corners and are smoother (almost shiny) than the others? Is there a coating on them? They were obviously melted before by someone to mold them into weights. Anyone have any answers or experiences?