I'll save you the drama Brad...
Stick with 165 Partitions and Varget and you'll not likely see any shift in impacts between now and middle summer. I've chronographed that load from -18 (as cold as the Chrony display will work) up to mid 90's It's in the 2710's in the dead of winter, and in the 2730's in the summer
Also, the difference in speed between 45.5 and 46.0 grains ain't worth the extra wear and tear on your brass... Bumping up that last half grain only netted me 20 FPS in the Montucky, worse accuracy, and bigger spreads. 45.3-45.4 is where it noded up in my Montucky, at a year 'round avg of 2720 FPS, and pretty much groups under 3/4" in any conditions that aren't completely insane...
