How the seller got the USPS to ship that rifle is still a mystery to me. I was told flat out, they do not ship them. PERIOD!!
Whoever told you that was grossly misinformed or plain ignorant of the regulations. They will not ship
handguns, but long arms can be shipped through the USPS. With centerfire rifles, you have to provide a copy of the receivers FFL when shipping. I mailed a .308 Winchester Browningto a guy down in Birmingham, AL not too long ago via USPS.