Sorry I don't have all the details but I started shooting the 300/221 last winter when I lived in Alaska. I was using 2400, velocities of various loads were somewhere in the range of 900 and 1150fps with a SMK 220gr. It was quite cold, 15F degrees. I was amazed at how each different load would move up or down vertically but would group 10 shots in less than 3/4 inch at 100yds.
Since then I have moved to Nevada and with the 2400 at 95F to 100+F degrees I get lots of variation in velocities resulting in some big vertically stringing groups. I'm talking maybe up to 8 inches and more from top to bottom.
I started working on some loads using AA#9 and my groups have tightened up nicely. If it weren't for the occasional flyer the AA#9 groups at desert temps would be just about as good as the 2400 at cold temps. I am still trying to sort out the flyer issue but I am much happier under these conditions using the AA#9.
Anyone else notice big changes with temperature, or better yet not notice much change at all with a particular powder?
Regards-
David
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