You have not been paying attention to California, which is where they often try new stuff out. CA has a partial and probably soon to be total ban on lead cored bullets on an environmental basis. The plan appears to be:
1. Ban steel-core ammo as ‘armor piercing.’
2. Ban lead core ammo as ‘an environmental pollitant.’
3. ‘You can have your AR-15s, but it will bankrupt you to shoot them’ because the only option left is bismuth and that’s expensive.
Or silver. Or gold.