Look up paper brightening and clay content of paper .
There was a toothpaste commercial long ago that showed that if rubbed long enough it cut through Rolls Royce black lacquer all the way down to bare metal with a soft toothbrush.
In about 1930 it was determined that the life of a 30-06' barrel was 30 seconds , .007 sec at a time or 10,000 rounds of the ammo of the day .
I'm a casual shooter and have fired 10k each of 45 Colts and 12 ga . Nothing else comes even close to that count from me personally. Aside from the shot bridge line in the BPS there's no appreciable wear in either one . The environment that I hunted the BPS in had significant amounts of DG dust all the time unless the was precipitation happening.