I'm also looking for a .338-.378 WBY. Anyone got some they'd sell ? Dummy rounds are fine. Infact just a piece of fired brass would work. I have plenty of .30 caliber bullets I could just glue in. I have quite a collection of cartridges new and old, and I know I will never be done, but I want to round out my .30 caliber board.
On the .30 cal board, I have .30 Carbine, .30-30, .300 Savage, .308 Winchester, .30-06,.300 WSM
, .300 Win Mag, .300 Wby Mag, .300 RUM