I hadn't thought much about it before, but the difference in overall barrel length between winter freezing temps and summer heat, is quite striking. This alone should be cause for elongating holes a tich.
For example and this should show some evidence of what I speak, the quarter-rib on a #1 Ruger binds if the gun is fired until the barrel is hot, just one of the reasons for them needing accuracy help.
This elongation from cool to too hot was written up in PS magazine as being upwards of .007". I have never measured one.
This makes me wonder just how much elongation there is between the tang screw and front pin on a longrifle's barrel, with the gun sitting in the summer sun or being shot hot during that time of year, or worse maybe, during the winter time?