Ive been reloading for about two years so I'm far from expert level. Early last year I had some loads worked up with imr 4350 for my .338. The tightest groups I had were 3.5" @ 100y. An old timer that I usually avoid because he doesnt stop talking recommended I start using H4831sc because it isnt a temperamental.
I came back to the range a few weeks later and and shot the same groups but they were 3" lower. It was 25 degrees colder. I bought some h4831sc and really like it. With sierra 250gr bullets I shot sub moa once I figured out how many grain of powder she liked. Then in the spring the tempature jumped up to 55 degrees. Im still shooting sub moa but the groups were 2.5" higher. I load 55gr vmax with varget in .223 and dont have this problem. I predator hunt year round in temps from -30 to 70.
Do any of you guys deal with this in big bore rifles. The temp range I hunt a .338wm in are usually between 0 and 65 degrees. The shots I take are usually around 150y but some caribou shots are as far as 600y. A 2.5" variance @ 100y translates to 15" @ 600y. Any suggestions on a less temperature influenced powder?
