I can tell you. I know people who can't pass a NICS check for having 1 DUI, or for steeling. And no, when they deign you they won't tell you why the denied you, even if you request to know why. I got constantly denied and delayed with no prior record. I had to go get finger printed by the FBI to get a UPIN number so I could buy a firearm, even though I had never committed a crime. I think that is the ATFs way of creating their database to include fingerprints of people who purchase firearms. No one could give me an explanation of why I was getting denied. Yes all the paperwork was filled out properly every time.
Now that it's come out that the ATF has been building a database of gun owners, it's starting to make more sense.
