battue,
The tight, stiff forend is one factor, but as other people have stated a good barrel doesn't shoot less accurately or change POI when it's hot. Douglas makes good barrels, as do a number of other companies. Many factory barrels are also good, but some aren't.
However, I would think skinny barrels are more affected by heat than those that have a larger diameter. If so, and Melvins rifles still group well even being extremely hot, then his stock and tight bedding must be a significant factor.
Another question would be is heat transfer less of a factor with synthetic stocks vs wood?
Addition: JB, your last reply beat me to the punch and I think you answered some of my questions. Also heat waves coming off the barrel would be less in cold weather and thus may answer part of the 65BRs original question and way some think LW barrels shoot more consistently in cold weather.
