Recently I was cultivating the idea about buying sinker mold for use and reuse of lead. what put me off was that lead will deform and I 'll need to process it everytime before going to sling. and doing that everytime made me think of the health hazards so I rejected the idea.
then I searched for high density lead free materials . found out this:
http://www.ecomass.com/frangible-projectiles/they have tungsten powder filled plastics with density of lead. I still wonder what's the price.
what i dont like is that they say "frangible" I think slingers would prefer them non frangible for reuse. maybe they have such a compound.
This could be the future ammo , implanted gps chip with adjusted density, for Olympic slinging.