How do you send a handgun in the mail?

Under US law, handguns may ONLY bemailed by a person that holds an 01 Federal Firearms License (Dealer) or a licensed Manufacturer in the course of trade shipments- and paperwork must be filed with the post office to confirm that.

Persons that are NOT licensed (if you don't know that you have a FFL, you don't) may SHIP a handgun using UPS or Federal Express using Next Day Air. If the firearm is crossing a state line, and is NOT being shipped to yourself, with VERY few exceptions, it must be shipped TO a FFL holder in the recipient's state.