Very "interesting" thread.
A .30-06 Springfield made in 1942 would have to be a 1903A3. They are plenty strong enough for the .284--or the .300 Winchester Magnum, or any other "modern" round. A bunch were rechambered (and the front of the bolt converted) to .300 Winchester back when that cartridge was introduced, because there were far more very affordable 1903A3s than Winchester Model 70s.
Several gun writers built a .284 Winchesters on longer actions not long after the round appeared, because (like a lot of rifle loonies back then) they believed the "deep-seated" bullets in the .284 case robbed it of significant velocity. (Which isn't true, for reasons too involved to go into here.)
I also seem to recall one of them (possibly Bob Hagel) built one on a 1903A3 ACTION. But I also do not recall whoever made the experiment having any major difficulty getting the .284 to feed.
It is NOT a "magnum diameter" case, so would suggest the OP try some .284 rounds (preferably dummies) in his rifle and see if they will feed. My suspicion is it just might, even without any modifications to the feed rails.
Of course the .284 doesn't do anything a bunch of other cartridges do for hunters who never shoot beyond 400 yards, but if he wants something "special," why not?
