The way I see it, CCW’s is an attempt at national registration. Do not surrender your prohibited hi-cap mags. Disassemble them. Spread the parts and pieces through out the house and property. Get them out of the safe or gun closet.
I don’t know if they’ll go for a total ban including existing mags. It would be much easier to pass a bill outlawing new manufacture, import, buying selling etc.
If they tried to outlaw possession, including the ones we own, they’d be creating millions of well-armed felons overnight. They might not want to take that step.
Or, they might.