Mail them up to yourself, care of someone you know, and have them not open the boxes. Good to go. Ammo sell where you are to pay for postage on the firearms. Sidearms take on the plane or have to send FFL to FFL.
Sorry, but no need to send handguns FFL to FFL when shipping to yourself. You cannot send by USPS. You must use a "common carrier" like UPS, FedEx, etc. While they have their own internal rules about shipping, they are not laws.
