So far all I have casted with is clip on wheel weights. My boolits have always casted heavy when compared to what the mold is supposed to drop at. I.E. the 130 grain cast at 133. The 300 grain cast at 316 etc. I have had zero leading using the passing fad Powder coating and had leading otherwise. It is just plain easier to me. I do have some pure lead and some tin solder and some linotype that I have been keeping for when my wheel weight supply dries up, I will start alloying my supply to replicate the wheel weights as close as possible. It must be noted that when you read the stories of Elmer Keith using "hard cast" lead in his handgun loads, he meant something like 12 BHN. There was no such thing as 18 BHN lead alloys being used back in his day. Anything harder than pure lead that was used in black powder, was considered hard cast.
I will agree that zinc is a bad thing. You should carefully inspect the wheel weights and cull any zinc weights. The lead ones will easily deform with a pair of diagonal pliers and the zinc will not. Also, the zinc ones melt at a higher temperature and if you see one floating at the top when the rest have melted, get it out immediately before it melts. Zn wheel weights will have Zn stamped on the side. The rule of thumb is, if you can't cut it with side cutters, throw it to the side. Once you sort enough of them, you will start to recognize the visual differences and will not the cutters to verify.
Pure lead does not fill out the mold well and is very soft. You have to add tin to help the lead to fill out and get good clean sharp edges, tin will also make it harder. Stick on wheel weights are pretty close to pure and will need tin added. It is my understanding that antimony in the alloy allows you to "temper" when you drop a freshly cast boolit in water. Supposedly you can go from 12 BHN to near 18BHN by water dropping it.
By the way, I have been using clip on wheel weights in a Lee 130 grain gas check mold with Lee ALOX lube in my 7mm rifles and have been pushing them to about 2200 FPS and have 0 leading issues with it.
Rosewood
I will agree that zinc is a bad thing. You should carefully inspect the wheel weights and cull any zinc weights. The lead ones will easily deform with a pair of diagonal pliers and the zinc will not. Also, the zinc ones melt at a higher temperature and if you see one floating at the top when the rest have melted, get it out immediately before it melts. Zn wheel weights will have Zn stamped on the side. The rule of thumb is, if you can't cut it with side cutters, throw it to the side. Once you sort enough of them, you will start to recognize the visual differences and will not the cutters to verify.
Pure lead does not fill out the mold well and is very soft. You have to add tin to help the lead to fill out and get good clean sharp edges, tin will also make it harder. Stick on wheel weights are pretty close to pure and will need tin added. It is my understanding that antimony in the alloy allows you to "temper" when you drop a freshly cast boolit in water. Supposedly you can go from 12 BHN to near 18BHN by water dropping it.
By the way, I have been using clip on wheel weights in a Lee 130 grain gas check mold with Lee ALOX lube in my 7mm rifles and have been pushing them to about 2200 FPS and have 0 leading issues with it.
Rosewood