If you are talking about rifle barrels that have been chambered then you are correct, however rifle barrel blanks be they contoured or not and even threaded are freely available and can be posted as long as they do not have a chamber, i have bought several the last one in April this year.
TB.
let me get this straight, you can buy a barrel and have it sent to your house but not a silencer/moderater.
"Men occasionally stumble on the truth, but most of them pick themselves up and hurry off as if nothing had happened" Winston Churchill http://planetairgun.com/index.php