A 7mm Rem Mag Bartlein shoots .5 MOA for 2000 rounds and then starts to do crazy shit. I’m well past that in my 300WM, around 2500, and it’s maintaining accuracy, although not as good as when it was new, 0-1000. A 300WSM should last longer than the 300WM, obviously.
Now if you shoot like a retard then you’ll fry your barrel more quickly.