Think I would be looking at a .300 WSM rather than a .300 win mag. The .300 Short ultra mag even a bit more preferred.
I thought that way for awhile but I've slowly changed my mind for one reason.
I have friends that hunt with WSM and they complain about trying to find ammo.
Another friend pointed out to me that if something goes wrong on a hunt, you can usually find .300 win mag at the closest country store. The odds of finding the shorter magnums are slim.
The old win mag has been around long enough to be fairly common and it does the job. Based on that, I'd lean towards it for hunting