I imagine his federal NCIC check came back with a hold. Basically, when a firearm is sold, they run a check with the FBI to make sure the buyer isn't a felon. That background check can come back with one of 3 possible responses (Proceed, Deny, or Hold). If you get a proceed, then you can walk out with your firearm. If you get a deny, then you can't buy the firearm because you have some federal disqualification from owning a firearm. If you get a hold, then they need to do more research on you. It could be because something popped up with a similar name, or someone else with your name is a felon, or the social security number doesn't match the name. Who knows. When you get a hold they will change the outcome to a proceed or deny within 3 days. If they have not proceeded or denied within 3 days, then the hold expires and the FFL can proceed with the sale without the check. So usually when you get a hold, you just have to wait the 3 days til it expires, then go pick up your gun. It happened to me once, not a big deal, though a bit of a hassle.