Federal Assault Weapons Ban (1994–2004):
Banned semiautomatics that looked like assault weapons and large capacity ammunition feeding devices. The law expired in 2004.
There were multiple attempts to renew the ban, but none succeeded.
The Biden administration is attempting to put forth another ban. Chances are it also will not succeed.
More (from Wikipedia) …
A study by Mark Gius, professor of economics at Quinnipiac University, studied the law’s impact on public mass shootings. Gius defined this subset of mass shootings as those “occurring in a relatively public place, targeted random victims, were not otherwise related to a crime (a robbery or act of terrorism), and that involved four or more victim fatalities.”
His study* revealed that “both state and federal assault weapons bans have statistically significant and negative effects on mass shooting fatalities but that only the federal assault weapons ban had a negative effect on mass shooting injuries. This study is one of the first studies that looks solely at the effects of assault weapons bans on public mass shootings.”
Meanwhile, “Gun background checks soar to record in March following mass shootings and gun-control bills.”
Mass shootings in the United States
What Does Background Check Show (Note: Nothing on mental health)
What Is Gun Control: Everything You Need to Know