it would take a long time Loki and would likely incite violence across the nation in the form of riots. People wont do that easily. I think the only method that could really work would be a register requirement and then extremely stiff fines for failing to report stolen weapons or failure to register.
Although me a insanely long SCOTUS decisions don't get along, (so in other words I havent actually read a decision) I think the SCOTUS has already ruled that the second amendment cannot be infringed by placing undue restrictions or requirements upon ownership. SO it would require an amendment to accomplish that register law. That and the conspiracy nuts claim that if the government KNOWS about your guns then they can somehow get you. Let me tell you all right now if this government wants you then they will get you no matter what your packing. so that is a long lost battle people keep in their heads.
So I simply don't know. I think the long and the short of it is we will see a ineffective "assault looking" weapons ban and a restriction on number of magazines. Neither of which is very effective. Neither of which will result in changing behavior.