Apples , Peaches and Oranges !
The barrels wear at the same rate. The chambers,receivers,gas port hole and buttstocks done deteriate at different rates. Wooden buttstocks fail and lugs wear on M1s. Gas ports erode on M14s do to susstained rapid firing. BCGs wear on ARs. Those are what I have repaired the last couple of years, limited experiences repairing M14s.
I have only one question ... does it matter if you have shot less than six thousand rounds through your gun !! ??