Ldoll:
Re barrel life in any rifle, depends on caliber, type of ammunition used, type of use (a lot of rapid fire is hard on a barrel), care and attention received and so forth.
Re personal experience, with the model 70 standard target rifle, factory barrel, 308 win caliber, the following might be of interest.
When last I fired this particular rifle, it then had well over 6000 rounds, National Match Course Competition, through it. Despite a lot of throught erosion, shooting off a rest, with a scope sight at 600 yards, the rifle held the 10 ring elevation (2 minutes of angle)with a goodly number of X's, with THREE DIFFERENT LOADS. Total score was 591 out of a possible 600 for 60 record shots. I lost a few into the 9 ring, out the right or left side, purely a case of my misreading the wind.
Not likely that all rifles would do this, but it does happen. Hope this helps some.