Depending on the bore size and powder volume barrels wear out at different rates.
A 4000 ft/sec bullet in a .223 cal will last anywhere from 1500 to 3000 rounds if taken
care of and not allowed to get to hot.
At these velocities the bigger the bullet the shorter the barrel life.
As stated there are other variables like twist rate, barrel size,type of bullets and so on.
If it is a hunting rifle chances are you will not shoot the barrel out soon. if you are hunting
P Dogs it will happen all to soon.
Normally velocities of less than 3000 ft/sec are very easy on barrels 3000 to 3500 are
exceptable in most cases but barrel life will be shorter.
Once you exceed 4000 ft/sec the barrel life realy goes down hill and at 4400 to 4500
you will be looking at 1000 to 1200 rounds before some accuracy loss appears.
This is not scientific, just my experance.
J E CUSTOM