Well, time for some input here that contradicts what has been posted.
I shoot both rifles and shotguns competitively. From very recent experience (Sunday), I can say for certainty that H-4350 is not temperature insensitive as is claimed.
I shoot a 6.5 Creedmoor with 41.3 grains of H-4350. I've been using the same lot of powder since the warmer Summer months. Just last week I checked long range data by shooting. The data had not changed. Temperature was 57 degrees and was entered into Ballistic AE along with the other atmospheric data.
On Sunday we had our little local Precision Match. It was very cold all day with the temperature from 36 degrees to 41 degrees at the end of the match. When targets were engaged at 760 yards, impacts were .2 Mils low. I thought my zero was off, not the drop data, so I added .2 mils to my zero.
Had many chances to check the 100 yard zero as we shoot paper during the match. Well, it was now .2 mils too high. I moved it back to the original zero. As long range targets were engaged, everything was low. I can only attribute the change in drop data to the cold temperatures decreasing velocity.
Ballistic AE has a "temperature sensitivity" parameter in the rifle profile reloading set up page where a number can be input as a decrease/increase in velocity per degree of temperature change. I had never used this part of the program. I entered "3" as in 3 fps change per degree of temperature and the output matched my actual for Sunday's shoot at the colder temperature. The temperature at the time of load development was 55 degrees giving a velocity of 2785 fps. After the conditions on Sunday were input with the Sensitivity feature enabled, the program output that the velocity was now 2743 fps and gave proper data for drop.
With H-4350's reputation as very insensitive to temperature, I was very surprised to see this. I also now believe that ALL powders have to be sensitive to temperature changes.
At 760 yards I'd bet the difference in air density has more effect on POI than temp sensitivity of H4350.
