Loads for 10" AR15
I'm having trouble with H110.
Here at 4000 feet elevation, the speed of sound is about 1150 fps on a summer day. I'm trying to work up a subsonic load for my 10" AR15.
10 grains of H110 pushing a sierra 220 will do 1115 with 6fps standard deviation. However, at 50 yards, that load will only group 2+ inches. I can't figure out why. My brass is all the same trimmed length.
I'm using winchester small rifle primers.
What should I do for better accuracy? I'm thinking magnum pistol primers might be a good start. Is H110 just a poor powder for my purposes?
Papa
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