Quenton
The odds are in your favor.
In my experience with dudes like that that are willing to brandish a weapon also have a criminal record, so that could be enough to have him either violated, or as cause to have his vehicle searched. A felon + firearm = jail, and one less count to get them sent away.
There's also a very good chance that there is more that he's in possession of than just a firearm.
either way he definitely broke the law, and you should encourage the police to follow through. considering that that dude is a blatant threat to public safety.