If you don't find anything used....
I heard Moon at Crescent Customs is spinning up AI bbls...
The guys I shoot with think he is the best.
I'm shooting a 300NM and 260 Rem. Love them both but the 300NM is my favorite of all the calibers I've had. Maybe would be a good option between the two calibers you are shooting if you are looking for something different. I know the bolt for 338NM and 300NM are the same, not sure about the 338 you are shooting, but if it is you would already have your bolt and mags.
Steve