I have to add that you don't legally have to have a copy of Dave's FFL to ship anything to him. FedEx does not even require that you have it, although it helps to have it handy because the employees don't always know that (ask me how I know ).Like CK said above, you ship to him, and since you already own the gun, he ships back to you. If you haven't shipped before, here's how I do it in California:
1)Obtain copy of Dave's FFL. Usually he emails it to you. Print it out.
2)Get a medium shipping box from FedEx. I ship mine in some sort of case for protection. Fill remainder of box with packing peanuts or the like so gun DOES NOT RATTLE OR MOVE. You wouldn't want it to slide around and maybe open the box.
3)Address it to Dave, insure it, adult signature it, and ship it overnight. I've heard recently you can 2 day it, but haven't confirmed.
4)Notify FedEx employee that it's an unloaded handgun, and show them copy of FFL. This is required and the only way to legally ship a handgun. This must all be done at a FedEx hub, not a store.
5)Wait patiently (yeah right) for it to return.