Good question Dave. I don’t know, but my opinion is no, since no sale is involved. People travel state to state with guns everyday without having to go through the transfer process.
The folks at Shooting Solutions know you. They’d probably be able to give you a quick answer.
Also, now that I think about it, back when I was playing with class 3 stuff, I had to send my UZI to Vector for some repair work. I sent it straight to them and they fixed it and sent it back to my house. I wasn’t required to go through an FFL in either direction.
Isn’t it also a common practice for hunters to send rifles to their destinations for a hunt to avoid all the airline hassle?
It may depend on whether the transfer is permanent or not.
You can ship a long gun from USPS to an FFL in another state. I shipped @Personofinterest a couple of guns when he lived in WA state. It was my first experience with that and a piece of cake.