6.5mm projectiles have superior ballistic coefficients to .308 projectiles making the 6.5 particularly well suited for longer range shooting. The common wisdom is that, as far as long range precision shooting goes, you get ballistic performance similar to a .300 Win Mag but with far less recoil and longer barrel life.
That is the first that I have heard that 6.5 CM has worse barrel life than .308. I had always heard that they were similar, but both way better than higher pressure cartridges and magnums. But I'm still learning so I may have misunderstood...
similar powder capacity, similar pressure, smaller projectile... its going to wear faster than a .308
but its not going to be a 2000 round burnout like some of the magnums