I been shootin wheel weights for neigh on to a year now. I just put em in my small Lee pot and when they melt, I seine out the steel clips.
I also stir the molten metal around after that, let it set for just a minute and skim off the sludge that raises to the top. From what I have been told this is Zinc as it is kinda clumpy and hard. Zinc takes a hotter temp to melt.
I then dip the molten wheel weight with a lg. table spoon and pour it into my heated .490 mould, let er set for bout 10 sec. and tap the sprue cutter with a wooden stick, open the mould and the purtiest silver .490 RB will drop onto my cushioned pad.
As I am an occasional shooter, I only cast up bout a hundred at a time, bout ever 3 mo. or so. Shoot em out of my TC Renagade with anywhere from 50 to 85 gr of 3f. All are pretty accurate and the cost is just pennies, as I got a 5 gal bucket of them for $10. Ain't seen no harm to my rifle gun yet.
Also borrowed a buddy's .60 cal mould and casted him up some for his smoothie and some for me as well. I was havin so much fun, I bought a .45 cal mould and did a hunered of them to shoot out of my daughter's rifle gun. BTW they do not expand well cause they are so hard.
I just don't think you could harm your barrel, as they are still much softer than the barrel steel. Some folks shoot them new fangled copper jacketed sharp pointed boolits, out of rifle guns with a lookin glass on top of it. Don't seem to harm them none too much either.
I'm gonna keep on a shootin these here home made rifle balls. Draw a fine bead on em son. Bobby