The US Air Force uses the Postal Service to ship all our M9 [Beretta] pistols to our local air base. They come in via Registered Mail. Both handguns and rifles being sent back for survey or repair go out the same way.
I won't use FedEx because they require a signature. I'm at work all day/week and the only FedEx terminal is at Buffalo airport...a two hour drive [round trip] from me...I'll refuse delivery before I'll waste twenty dollars of gas to pick up a parcel I already paid shipping on...