Thirdpower has mad details at his place about the Cook County Gun ban. I only want to cover one little piece, which is their new definition of armor piercing ammo.
Metal piercing bullet means any bullet that is manufactured with other than a lead or lead alloy core, or ammunition of which the bullet itself is wholly composed of, or machined from, a metal or metal alloy other than lead, or any other bullet that is manufactured to defeat or penetrate bullet resistant properties of soft body armor or any other type of bullet resistant clothing which meets the minimum requirements of the current National Institute for Justice Standards for “Ballistic Resistance of Police Body Armor”.
One of the rounds that would be banned by this would be the completely copper self defense rounds from Magtech. Off the top of my head, I can’t remember if anyone else makes a lead free round, but I’m pretty sure that someone does. I know that companies are moving towards lead free because they want to reduce lead pollution, so Cook County is banning non-toxic ammo there as well.