The older wheel weights were alloyed with tin and antimony ( some times zinc ) making the lead way too hard ( ok for smooth bores )
Many and most wheel weights today are steel, zinc or other non lead material.
If you try to use it in a Colt/Remington revolver you will break the ram handle.
Some hunters like a hard ball for penetration, like I said previously, it will work ok in smooth bore, with a patch.
If you are casting for muzzle loaders and modern guns, it is well to keep you lead well separated, so that you don't mess things up.
I am quite sure that shortly lead will be regarded as a real hazardous material, and will put us out of business.
We will have to shoot marsh mellows, or wood sticks.
Fred