Bagman is an illegal drug user, and addict. The military dismissed him from service for that. The video we have from his computer, etc., show he is just as actively using illegal drugs today.
To purchase a firearm, Bagman had to fill out a federal background check form.
If he truthfully answered "yes" to question 11 e about being a drug addict--which he is--then he would have been rejected for purchase of that firearm.
He was able to successfully purchase the firearm, so either he lied or the dealer ignored their legal responsibility for due diligence. If it were the latter, it is almost certain that person would now be facing charges.
We know the Secret Service swooped in and collected the background check form and other paperwork surrounding Bagman's purchase. This is highly suspect since it's outside the purview of that agency to be involved in a federal firearms crime.
Bagman also left the firearm at his girlfriend / whore, or whatever place where she subsequently threw it in a dumpster behind a store where it was found and turned in by a dumpster diving homeless guy.
So, there's plenty of evidence to charge Bagman of at least two firearms crimes, both felonies. Why hasn't he been charged, or for that matter, even investigated?