I think we should push for a re-opening of the NFA registry.
Only one or two legal machine guns have ever been used in crimes. Statistically, they are less harmful to society than lightning strikes.
If they offer us re-opening the NFA registry in exchange for background checks, maybe that's a deal worth making.
Funny thing is that I do support background checks. I'd have supported them if they'd asked. But they didn't bother to ask - they decided to use the power of their offices to bully instead. That is not what government is supposed to do.