I've been paying attention to EKW for a bit over a year and either the barrels sell as quickly as ammo at Wal-Mart when offered...
...or they haven't listed a barrel for sale on that site in over a year.
I would contact eric, he's been 100% with me would highly recommend. I believe EWK isn't his main job and he does work as time permits. If you call about something that's out of stock he usually can give you an estimate on when it'll be in.