jwp,

When the Ramshot ballistic lab tested powder for temp sensitivity, they used ammo that had been chilled or heated--which has been done many times over the decades. In fact that's what Bob Hagel did for the results listed in his classic book, Game Loads and Practical Balliistics for the American Hunter.

But when I started testing powders for temp-resistance in the 1990s, I found that sometimes just heating/cooling ammo didn't produce the same results as when actually testing BOTH rifles and ammo in different temperatures. In fact the results only agreed maybe 20% of the time. There are several reasons for this, but it's why I don't trust results shot with ONLY the ammo heated or cooled.

This is also why the test results I list in Chapter 10 of The Big Book of Gun Gack II were primarily shot at actual temperatures, not with just the ammo heated or cooled.

Might also mention--as I have many times in various articles and books--that just about any modern smokeless rifle powder will produce very consistent results at any temperature from the 20s to 80s Fahrenheit, at least for typical big game ammo.

It's also well-known among Shrapnel's friends that he almost never hunts when it's really cold or hot....

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John Steinbeck