I view the usable life of a rifle barrel like the tires on my truck, they will last just so long. With that said if you are very concerned with the round count on your rifle barrel I'm guessing 2000 to 2500 rounds down a .300 Winnie pipe versus a 1000 to 1500 rounds for a 300 RUM as long as you follow good cleaning practices, don't overheat the barrel, and stay away from the lighter bullets.
If your shots are limited to 500 yards the Winnie may serve you best, beyond this mark the Ultra really starts to shine with the 200 NAB.
Of course I like several of the big .300's and the Ultra is one of them! I have been very impressed with the inherent accuracy of this big 30! Of course I have had great accuracy results from the 300 Winnie and the 300 Roy. A moot point maybe that you can find .300 Winchester Ammo or components almost anywhere.
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