Background checks.
Red flag rules/laws, you have to go to court to reverse this, prove you are ok.
Assault weapon ban.
Licensing of people who sell more than a number of guns a year, which means background checks for their customers.
We will have a far better situation in terms of mass shootings, and in cities like Chicago, where guns are purchased 30 miles away in Indiana, and brought into the city. Make it harder to get and transport weapons across state lines this way, much harder.
They are bitching about Biden and the 94 crime bill, but one of the items in that bill was the assault weapons ban!