HOW!
This is how,
Here is exactly what the ATF 'Federal Firearms Regulations Reference Guide' (ATF P 5300.4) says:
(B9) May a nonlicensee ship a firearm by carrier?
A nonlicensee may ship a firearm by carrier to a resident of his or her own state or to a licensee in any state.
A common or contract carrier must be used to ship a handgun. In addition, Federal law requires that the carrier be notified that the shipment contains a firearm and prohibits common or contract carriers from requiring or causing any label to be placed on any package indicating that it contains a firearm. [18 U. S. C. 922( a)( 2)( A) and 922( e), 27 CFR 178.31]
B8) May a nonlicensee ship a firearm through the U. S. Postal Service? [Back]
A nonlicensee may mail a shotgun or rifle to a resident of his or her own state or to a licensee in any state. Handguns are not mailable. A common or contract carrier must be used to ship a handgun. A nonlicensee may not transfer any firearm to a nonlicensed resident of another state. The Postal Service recommends that longguns be sent by registered mail and that no marking of any kind which would indicate the nature of the contents be placed on the outside of any parcel containing firearms.
But, if you have an FFL..............
Licensed persons can ship a rifle, shotguns,
or handguns by US Mail. In fact, we suggest that you use the USPS as it is now the most cost-effective way to ship a handgun. To ship a rifle or shotgun, you need only inform the Post Office that the package contains a firearm. A licensed manufacturer, dealer, or importer can ship a handgun via the US Post Office if the licensed dealer fills out a US Post Office Form PS 1508 and files it with the local Post Office branch where the handgun is to be shipped. You can search the US Post Offer Postal Explorer site for specific USPS regulations regarding firearms and ammunition.
I always go through my local dealer when I need to ship a handgun, may cost you a few bucks but it beats having the Feds breathin down your neck!
Mark