A mass turn over or confiscation of certain types of weapons, to what end?
I don't even think a federal ban of a specific type can pass at this time or maybe ever.
Here's what I would like to see at the federal level:
A major crackdown on traffickers of illegal guns.
Stricter punishments for any licensed dealer who does business out the backdoor or under the table.
Facilitate more efficient sharing and updating of background information and trace data.
Prosecute federal gun crimes.