With huge array of high quality bullets available for the 338 and the ballistic compensating scopes that are available, I can't think of one thing a .300WM does better than a 338WM inside 500 yards. I'm a very recent 338WM convert but it has allowed me to get rid of two 300WMs.
Nothing except shoot flatter with most similar bullet weights (and would likely shoot flatter with 250's as well, but I haven't personally tried any in a 300 mag to have an opinion on same), and everything else being equal, out penetrate given the same bullet weight. Yes, small differences, but no "smaller" than the "bigger hole" argument you offer. If one is a "twirler", IE. fiddles with his turrets before shooting, yes, any cartridge can be dialed-in... why not use a 338-06 then? Or a 30-06? Or... Barring things like Grizzly, I always found the 338 Win killed better with a 200-ish grain bullet. It didn't take long to settle on a 225 Barnes TSX in the 340 running just shy of 3100 though, although the Partition of the same weight always performs superlatively as expected with that bullet.
But back to the original comment..... again.... make the various 300 Magnums obsolete? I don't think I've ever heard such an assinine statement.
I guess that the 338 Winchester Magnum is so superior to something like the 300 Winchester Magnum that any organisation that uses the 300 Win Mag in the sniper role will be rushing out to replace their obsolete 300s with 338 Winchester Magnums? 338 Lapua, yes, THAT does offer some advantages, but 338 Win? A resounding "NO".






















































