Wheel weights

So I made a bar took it to yard and they told me it is 50 50 zinc lead ??
so I am almost sure during some kinda transition wheel weights where also made as 50 50
some are Zinc
I am told Ammo people do put a little zinc in with the lead so the 50 50 might be desired
can any one help with whats up ?
From what I am reading 50 50 is great for larger calibers