First barrel, the factory C-M, started to degrade accuracy after about 3000 rounds.
The second, a Pac-Nor SS match grade, was good for 3500 or so, then it started
to show erratic tendencies. [If a 6.5 barrel will not maintain 1.25 moa, it is gone]
The barrel on there now is a Shilen Match grade SS. It is a .5 moa barrel with at
least 4 different loads.
I usually load to extract as much potential as is safe. Milder loads would give more
barrel life, I am sure. It takes a lot of shooting to wear out a barrel. 3000 rounds
at an average charge of 48 grains equals approximately 20 lbs of powder to wash
out the throat. [My first barrel had no rifling left for 5 inches from chamber]

Dave.
For the record, I do not shoot long strings of rounds to make the barrel very hot,
since that will shorten barrel life a lot. I had an acquaintance who washed out his
6.5/300 Weatherby barrel in 700 rounds. D.