Here's a different wrinkle on this subject. While shipping out of state has been covered well on other topics in this section, how about selling a firearm while physically out of one's home state?
Let us suppose, for example, one had a firearm (assume everything legal, from acquisition through transport and possession in the OTHER state) and traveled from the home state to another, possibly on a trip. Further suppose one goes to a gun show there and just happens to have a good price offered on the firearm. Is it an out of state sale?
The buyer, say, an individual not a dealer (with FFL) wanting to buy it, is making the purchase in his/her home state, in compliance with Federal law. I realize the complication of intent, that is, someone could accuse the seller of transporting the firearm in order to sell out of state; and, this may be it's undoing.
I suppose the question is how federal law is applied here. The seller isn't shipping it.
The question is more or less academic, as I have no plans to do something like this. But, if I had something along on a trip and someone offered to buy it or trade something intresting, it would be helpful to know where I would stand.