A couple more tidbits from that survey...
Among prisoners who carried a firearm
during the offense for which they were
serving time in 1997, 14% had bought
or traded for the gun from a store,
pawnshop, flea market, or gun show.
The 1997 percentage who had
acquired their firearm at a retail outlet
represented a significant drop from
21% in 1991.
91 would, of course, be Pre-Brady-
The percentage of
inmates receiving their gun from family
or friends rose from 34% in 1991 to
40% in 1997.
So a third of criminals got their guns from friends and family before Brady, post Brady background checks, the 7% that didn't get them from retail locations appear to have gone to friends and family.
Again, this survey is admittedly old. and I don't know that I trust a single survey to prove anything. But it's certainly suggestive
of the fact that background checks influence where crime guns come from.