My view on this, though simple---is this. If it does sunset, what will change? Not one thing. States will do as they do and the federal law will mean nothing. Example: California:
You still will not be able to own anything new, as they have their own ban concerning assualt rifles and high capacity magazines.
So do many other states, and the ones that don`t---will either revisit changing their laws or let them remain. Lot a hoopla bout nothing.