The vast majority of guns ‘in the wrong hands’ are stolen. Plain and simple - that’s where they come from.
They form burglary teams that specifically target homes that they suspect have guns, and sell the stolen goods outside of government supervision.
Next biggest source - straw buyers.
The incidence of a criminal being caught with a gun he purchased at a gun show (sans background check) is rare enough to be newsworthy.
Background checks don’t stop the trade of stolen guns or straw bought guns.
Me personally? If I sell a gun, I will do it through a dealer. I don’t know all the laws...and if I accidentally sell a gun to a felon, I’m not sure what that means to me. And I don’t know about my liability for civil action, if the guy turns around and kills someone. So I cower under the government boot, and plan to obey.
I bought my trap gun from a site called trapshooters. We didn’t know each other and I’m now looking to upgrade again. That means I’ll list my gun there and buy another one there. I don’t see any issues with that, I don’t think its anyones business either