If this is addressed to me I reamed my 338-284 barrel from a A+B 338 fed barrel years ago when the 338 fed was popular and midway carried those barrels, cut it and crowned it.
IE a 338-284 ream will clean up a 338 fed chamber.

Its for sale along with dies, brass etc.

You can get Shaw 338-06 savage barrel kit from Brownels but they are backordered.