What did M14 Doctor have to say when you asked him?
Irons or optic?
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I would remove the scope and retest the accuracy at 100 yards with irons... hope that helps.
I did that. Same results. It's not the scope.
Is it possible that because of the shorter barrel the bullet doesn't fully stabilize until it's past 100 yrds? I'm thinking it might be keyholing when it hits 100 ?
Are the conditions you're shooting under absolutely identical (same stance, same rest, same sling, etc.) for the 100 yard and 200-300 yard shots? I'm wondering if some small, seemingly unimportant change is affecting your patterns.
Now I'm curious and kinda wondering why I didn't get a p.m. about it.
What muzzle velocity are you getting with that load/powder?
Does it group good then open up the more you shoot it? Does the POI change in any pattern?
Are you able to post any pictures of the groups at 100, 200 and 300 yards?
Shoot it at paper and report back. You might be simply shooting over or under the plates at 100 and calling that a larger group size.
I did shoot it at paper. I just gave the plates as an example. But, it prints 6-8 inches at 100 on paper and under 3 inches at 200 and 300...consistently.