In advance of the Giffords gun forum in Las Vegas, Joe Biden has announced his gun plan, which he touts as more "moderate" than those of his rivals. The highlight of the plan is that owners of "assault weapons" would be given a choice: either turn in their guns (for compensation) OR register them under the National Firearms Act. https://www.huffpost.com/entry/joe-biden-assault-weapons-gun-policy_n_5d942938e4b0e9e76054d9c3 The main reason this won't fly is that, thanks to Beto O'Rourke's honesty, everybody now knows that registration is the precursor to confiscation. Therefore you would get a very low rate of compliance. Beyond that, NFA registration is simply impractical. The number of AR-15's, etc., is exponentially greater than those of machine guns, SBR's, etc. You would need an exponential increase in ATF staffing. And approvals for transfers would take years. This would effectively freeze the guns with their current owners. (That's assuming that there was compliance.) Sen. Feinstein considered such a plan in 2013, and rejected it.