I have only used 760 from 80 to -17 degrees, and never noticed any change of impact. Hunting not target shooting. I might never notice on animals. Now I need to do some cold weather tests. I haven't read MD's test results yet. I will look them up, he is always a good read.
I published an article on the subject in
Handloader or
Rifle years ago, which eventually was republished with some additional infor as Chapter 10 in
The Big Book of Gun Gack II, "Temperature and Rifle Powder." It shows the results with various cartridges from the .17 Hornady Hornet to .375 H& at both 70 and zero degrees Fahrenheit, and sometimes with the ammo heated to up to 115 degrees.
The biggest point-of-impact shift I've seen from 70 to zero was three inches at 100 yards, which probably wouldn't affect shooting a deer in the chest at 100 yards--but would at longer ranges, which as I relate in the article is exactly what it did on a mule deer doe at around 250 on a cold morning. Luckily, the doe was broadside facing to the right, and I aimed behind the shoulder to minimize meat destruction. But the bullet landed right in the middle of the shoulder--which is why I retested the load at zero degrees on paper a few days later and found the 3-inch shift--and also found the load lost 130 fps from 70 to zero.
But also also depends on the rifle itself. If a particular rifle, for instance, doesn't change POI much with different bullet weights, it's also not likely to shift at different temperatures. This tends to be the case in heavy-barreled rifles, especially chambered for .17-.224 varmint rounds. The only way to make sure about typical big game rifles, however, is to test them at varying temperatures.
I have yet to find such a shift in temperature-resistant powders such as the Hodgdon Extremes, and even some not advertised as temp-resistant. Most of the original Ramshot rifle powders--TAC, Big Game, Hunter and Magnum--are about as good as the Extremes, with the exception of Hunter, which usually loses about 100 fps from 70 to zero. But again, the rifle we use Hunter in most is Eileen's NULA .257 Roberts, which has a #2 Douglas barrel that's full-length bedded in the very stiff NULA stock--so POI doesn't change.
However, have yet to test any powders at 70 and at 100+ degrees that don't gain velocity at temperatures over 80, even the Hodgdon Extremes--but they don't gain as much velocity (and hence pressure) as "standard" powders. Powder compression and the primer can also make a difference.
The chapter contains a lot more detail than this post, of course. Eileen's been throwing a 25% off sale "Leap Year" on all our books since mid-February, and today is the last day. The regular price is $32.75, which like all our prices includes media-mail shipping in the U.S. The shipped sale price of
Gun Gack II is around $24.50.