How about banning triggers?
Think about it. That would stop all those shootings, and eliminate any unanticipated loopholes.
As an added benefit, ‘triggers’ cause snowflakes to flip out, and should be banned for that, also.
It’s a virtual certainty that groups bent on nefarious use of such items are first going to get in trouble in other ways; such bans aren’t needed. Nor are they practical. Allow the patriot groups to have them. The danger is near zero and the benefits could be great. Mass shootings rarely happen in well defended areas.