I'm in the same boat shooting IMR 4350 in both of my elk rifles. I sight in in rural San Diego County at about 4000 Ft of elevation and somewhere around 75 degrees. It will be close to 90 today. We hunt at 7800 Ft on average in Colorado at around 25 degrees any morning or evening.
One of my younger, very technical shooting friends who thinks you need a ballistic program to pull a trigger was terribly worried about the climatic differences. I explained to him that I'm the biggest source of inconsistency in the field shooting and that he was full of crap..... but feel free to run the numbers and let me know.
When he figured the difference it was .2 of an inch at 400 yards and I assured him that even though I've always thought my marksmanship is stellar - that I wiggle a heck of a lot more than that at 400 from a field rest. Last year at 550 yards my 2 shot group was middle of elk vitals with all that inconsistent powder, elevation, and barometric pressure working against me..... funny how those bullets keep hitting where the crosshairs meet hide.
