Strip the gun into two parts and mail it home in two separate packages. Once you break it down it is no longer a firearm, it’s parts and not illegal to mail in the regular postal service.
You only need a dealer if the gun is functional. A frame without a cylinder, or a receiver without a barrel is parts. A pistol without a magazine IS still a gun, it is just considered unloaded. You could place a single round in the chamber and fire it.
Once you break it down it is no longer a firearm, its parts and not illegal to mail in the regular postal service.
It would be an excellent reform in the law, if functionality was required. But I do not believe it is.