This is the one thing that has kept me from rebarrelling my rig into the 338 Norma, or his little brother, the 300 Jazz. Nobody seems to have any brass. I can't imagine why Norma would introduce a new round and then not have a good supply of brass on hand to keep shooter's interest in the new round. Seems like a major marketing faux pas to me, but maybe there is a better explanation?
Good luck in your quest. Be sure to post back here when you are successful. I'm sure there are many others besides me that are watching this issue and cartridge with great interest.