Well according to this, most if them get them from ummm, extra-legal ways.
Look at this, only 19% of firearms used by Federal prisoners were bought from licensed dealers (I am including gun shows, were 99% of buyers go through a FBI background check)
At least some of these guys were not convicted felons at the time of their arrest, so we can assume the system has a less than 15% failure rate. Not too bad for government work. Another thing that is left out of this is the "straw sale" were a person legally barred from buying a firearm gets someone else to buy it for them. There is not a whole lot that can be done to stop such sales, unfortunately. Gun dealers I know have seen a lot of them, and worked with Law Enforcement to have the perpetrator arrested. Nice fact: straw sales are very often done by the convict's mom. For real. Another point to think about when looking at this information is that some of these upstanding gents were no doubt lying. I don't know about the other 6%, but I do think its safe to say they didn't get them legally.
Before you ask - I don't have any documentation to back up this graph. We here at Homemade Defense don't do that kind of shit. Pay here is low.
Who lets someone borrow a gun? "Hey Cletus, lemme see that shotgun, the wife's been cheatin' again"
I mean really.
So, "gun control" advocates, gun grabbers, and the dedicated professionals at the ATF, focus on the largest part of this that you can impact. Dealers and Fences. If it can be proved that you stole a gun, you should receive a heavy prison sentence. Like 10-15 years. The whole point is that legal guns in the hands of adults in this country make up a very small portion of gun violence, and as that is the case, law enforcement and those great folks who feel the need to save the rest of us should direct almost all their efforts towards illegal guns, not legal ones. How about unannounced searches of the homes of those on probation or parole for firearms offences? How about a PSA? Give a gun to a felon, do his time for him? Something like that?