I will say that when you work up reduced loads using fast burning powders, especially pistol powders, that as the charge goes down, the heat goes down. It isn't a matter of pressure, because I've got a 17 FB load using TiteGroup that runs what seems to be very close to full pressure, and I can fire 3 times the rounds that I can with "standard" powders before the barrel gets hot.
I've also noticed that single base powders in full charges generate less heat than those using double base powders. And that cases full of powder warm up a barrel faster than cases with less fill. Seems like less powder would equal less barrel erosion, since erosion is a product of heat, but I have never been able to discern how much it matters. Not enough, I think, moving between 90% case fill and 105% case fill.
