Confiscation of semiautomatic rifles in Chicago area town
So, once they figure out you own an assault weapon in this town, they want you to give it up to their police force. Not remove it from their jurisdiction, sell it to someone else, or destroy it -- the daily fines continue until they have it in their hands and you do not. That's a definite escalation from other attempts at gun bans that have focused on banning new manufacture or sale while grandfathering existing firearms.
The actual ordinance is more precise. It's a one-feature test. Semiautomatic, capacity to accept a detachable magazine, plus one feature (including a pistol grip, forward grip, thumbhole stock or other scary stock types, shroud, or anything scary on the muzzle).
In practice, that means almost any semiautomatic firearm with the capacity to accept a magazine regardless of size (since you can always find a standard-capacity magazine).