shipping a rifle to myself

Trying to ship my M96 to myself from my home to the state I'm stationed in(TX->SC). Never shipped a firearm before so I had some questions for anyone who has done this before. Is it easier and/or cheaper to go through USPS or an FFL? Does USPS or the FLL package the firearm for me or do I need to find a long enough box for the rifle? Thanks all.