THAT is bullshit. The cops had no legal right nor reason to accost him that way. I hope that guy sues the fuck out of those two cops and the department itself. IT IS NOT ILLEGAL FOR A RESIDENT OF USA (That's right you don't have to be a US Citizen if you live in USA and are not a criminal you have Constitutional Rights) you have the Right to buy a gun or any unspecific number of guns. The 2nd amendment puts on such boundaries or restrictions on buy or owning or carrying a firearm. A person can legally sling a rifle, put a gun on his hip, have another in a pocket and still more guns in his vehicle at NOT be in violation of the 2nd amendment.
This looks like a case of illegal search and seizure, kidnapping, police brutality...and more.
I seriously hope this man hires a good lawyer and wins a suit against this Gestapo like policy and practice.