Actually, USPS is an accepted common carrier for long guns but NOT handguns. One must alert the carrier as to contents and receive a receipt of delivery. Also, it's perfectly legal to mail a long gun between parties WITHIN the same state. It is not the law to require the sale of private arms to be sold under a Federal Firearms Licence, thus we have the so-called 'gun show loophole.' Yes, I could arrange to buy a long gun from say, The Alaska Outdoors Forum (private owner) and have it sent by mail.