Barrel wear is just part of the game in my books...
If a person could see the throat of a barrle at the cone where the bullet Slams into the rifling it would scare the crap out of us...
My friend calls it the flash,,, kinda like a oxygen and acetylene torch being lit under extreme pressure...
It is said that that flash is so hot that it turns the little edges of the cut rifling red like steel that is about to melt...
Probilibly like the stuff we see in a lava flow...
So a good tool to find out the rough estimate of barrel wear is google a search of """Over Bore,""" the last chart I looked at ranged from 222 hornet on up to the 50 caliber BMG...
All I can say is there are """alot""" of barrel burners out there,,, the 2 calibers / cartridges that are right up there are the 270 Winchester and 7mm Remington Mag,,, let's not forget that there are 20 to 40 other cartridges if not more that fall into the 1.000 and above category...
Cartridges below the 1.000 see better longevity,,, of course the 0.700 to 0.835 seem to last alot longer...
308 Winchester's are in this 0.835 category if I recall... I could be off on these numbers... Ha
Cheers from the North