We are really addressing two issues.
1. The shipping of the gun. And,
2. The transfer.
All transfers to out-of-state buyers MUST be through an FFL holder. This is law. No exceptions, that I'm aware of.
The technical aspect of shipping this firearm is a bit different. The frame must be sent to an FFL holder. If it is shipped separate, it may be sent as gun parts, without the requisite hassels of shipping a handgun. Same for the barrel, except it doesn/t have to be shipped to an FFL holder.
If I were doing this, I would either:
1. ship the frame to the dealer, and the barrel, grip & forend to the buyer, or
2. Go to my local dealer, and have him ship the whole thing to the other dealer.
Either way, you must first have in hand a signed copy of the receiving dealers FFL. My local dealer doesn't charge me for transfers of this sort, just the shipping. I usually use him, because he isn't restricted to the overnight rule, as I would be. FWIW>>>>>>>>>>>Bug.