The govt can do anything it wants. They could grandfather all current AW. THey could go the route of Australia & full on ban on ownership, just demand a turn over & they will give you some paultry amount of money. IT could happen. I doubt it, but it could. There is a constitutional issue of illegal seizure & forfiture of property, but they have gotten around that with current drug laws.
Mags, they could certainly ban them, wouldn't even need a new law, just decree it so for public safety reasons. Mere posession could be a felony, much like marijuana used to be. Anything could happen, we'll just have to wait & see, but IMO, better to spend some money now if you want something, if this stuff is banned, grandfathered in or not, you can't buy it going forward.
Yeah, another thing I see happening will be a ban on ALL gunshow sales unless they go thru a FFL process. Again, all BS, when you consider the top ATF guys are running guns to Mexico for cash.
There is a long standing reason why ALL liberals want guns banned. You can not be a tyrannical govt if the people can't fight back. How are you going to enact 75% tax rates & force people into public transportation, global warming taxes, etc if they rebel? Rebelling w/o guns is a loooong hard road, just look @ Syria today.