The .300 Win Mag is an awesome round. Probably the best.
.338 Lapua is better. Brits and Canadians using the .338 for a while now. I believe USSOCOM uses .338 but they get whatever they want.
.300 Winmag is an upgrade over 7.62x51 NATO for sure though. Especially at the ranges of shots taken in Trashcanistan.
The .300 Win. Mag. is a good round and better than the .308 but not by that much. It is not all that much more powerful than the old 30-06 if the 06 is loaded to it’s potential which it never was.