A few comments:
Most modern powders don't vary much from about 30-80 degrees.
Temperature sensitivity, as some mentioned, can vary with the particular cartridge and bullet weight.
It also varies somewhat with loading density. A full case of powder, slightly compressed, is usually less senistive.
The primer can make a measurable difference as well.
Heavier barrels usually result in minimal point-of-impact or accuracy change, even when velocity changes considerably. Lighter barrels can show considerable variation in both, but you won't know how much until you try 'em.
Chilling or heating only the cartridges usually won't show the same results as shooting in colder or warmer temperatures, but occasionally does. If you're really interested in hunting-condition results, test at the actual temperatures you may be hunting in.
