It doesn't have all that many rounds through it, 437 according to my notes. Haven't looked at the throat through my bore-scope lately, but doubt it would show any erosion at all. That's based on looking at the throats of a lot of hunting rifles, some shot a lot more.

My guess is a 7x57's barrel will shoot accurately enough for big game hunting out to 400 yards for several thousand rounds.

“Montana seems to me to be what a small boy would think Texas is like from hearing Texans.”
John Steinbeck