In a follow on from the barrel life thread I have some questions. I've often seen it said that you should let barrels cool between strings of shots to prevent excessive barrel wear but after some consideration I'm given to suspect that there can't be any foundation for this claim.
What is the mechanism by which shooting a warm barrel damages the bore? If you consider that the barrel is normally at 20 degress, or about 293K, under ambient conditions (OK, not anywhere close this winter/spring but I need to start somewhere) and that it needs to approach 80 degress or about 350K to be too hot to hold, which is the measure of "too hot" that seems most commonly used on the forums I frequent, then how does this cause any change in state of the steel barrel? In turn how does this change in the state of the steel cause the barrel to wear out?
As an engineer, though with no knowledge of this specific area at all, I fully believe that barrels wear out and that different cartridges, and different loads in a given cartridge, can result in different rates of wear. What I will not believe, until someone can describe the exact mechanism, is that shooting a warm barrel, at a few tens of K above ambient, can have any significant impact upon the life of a barrel which is regularly subjected to extreme high pressure events with a flame front temperature measured in thousands of K. I just can not see any mechanism by which starting say 60K higher than ambient can be a major or significant factor in an event which might occur at 6,000K above ambient.
As an aside to this despite many questions on various forums I have yet to find the potential life of my Blaser barrel as I can't find anyone who has worn one out. This can only be a good thing.