gun shows? private sales?
private sales are protected by the constitution.
and gun shows DO require background checks. they always require you to seek out an ffl dealer when you try to pick one up. or they are one already.
also, allllll the guns from all these recent shootings were bought from retail stores. with background checks...
and they were all legal legit owners.
you cant really stop people from stealing a gun from another person though. there isnt really a check to that.