Not like I am making something up. It is common belief to let the barrel cool between shots. So I am saying you are being disagreeing cause I wrote. This is site where I can not say anymore than that.
I don't need to take about thermal coffecients, though I suspect I have great deal more education on it than you. I have seen what happens with hot barrels. I could as poorly educated as you, and and still observe this. No math needed.
All I did was say the guy should try speading the shots out and see. Not like I am asking him to spend any money or make any effort. Very easy to try. If if it doesn' work he is out an hour. But you would rather argue with me than help someone.