Originally Posted by Mikecr
For long range shooting, there is no way I would use a single gun for a range of 40-90degs.
Two of the barrels used on my .30-.338's were fired in competition in temperatures from the upper 20's (Raton, NM, early March) to high 90's (Port Clinton, OH, late July). Both held the same load of IMR4350 and RWS 5341 primers to under 3/4 MOA at 1000. Wish I'd been able to put 'em on paper that well in the cold weather when 'twas hard to hold still shivvering like jello in an earthquake.
I've had similar experience with .308's over almost the same ambient temperature range and observed no significant difference in accuracy through 1000 yards. But the zero will change; cold air's thick and cold powder's weak so the lower muzzle velocity means more drop. Hot air has the opposite effect. Such is life.