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Rifles, Reloading, Optics, Equipment
Reloading
Need help interpreting OCW development for 308 Varget and 175 SMK
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<blockquote data-quote="new2mud" data-source="post: 1789429" data-attributes="member: 24831"><p>It is for a .308, 20.5" 1:10 twist barrel, loading 175 SMK with Varget.</p><p></p><p>I've done several Optimal Charge Weight (OCW) developments, but this one has my head scratching. I know in OCW development you're not supposed to focus on the tightest groups, but rather POI shifts--however, the data on this one is confusing to me. (Ignore the top left target--sighters)[ATTACH=full]165230[/ATTACH]</p><p></p><p>Often the accuracy node is the charge weight that provides the lowest SD. In this case, however, 2 consecutive charge increments had the lowest SD: 43.9 grains and the next step up at 44.3 grains had SDs of 3.3 and 4.5, respectively. However, they went from horizontal stringing (43.9gr) to vertical stringing (44.3gr), and grouped around 1-1.1 MOA.</p><p></p><p>From the target picture, 43.5gr and 45.1gr (the low and high of my charge weights tested) had the highest SDs of 19.7 and 13.6, respectively, yet had the tightest groups (0.61MOA and 0.72MOA, respectively).</p><p></p><p>Could I get some collective help in interpreting this data and suggestions on where to focus next?</p></blockquote><p></p>
[QUOTE="new2mud, post: 1789429, member: 24831"] It is for a .308, 20.5" 1:10 twist barrel, loading 175 SMK with Varget. I've done several Optimal Charge Weight (OCW) developments, but this one has my head scratching. I know in OCW development you're not supposed to focus on the tightest groups, but rather POI shifts--however, the data on this one is confusing to me. (Ignore the top left target--sighters)[ATTACH=full]165230[/ATTACH] Often the accuracy node is the charge weight that provides the lowest SD. In this case, however, 2 consecutive charge increments had the lowest SD: 43.9 grains and the next step up at 44.3 grains had SDs of 3.3 and 4.5, respectively. However, they went from horizontal stringing (43.9gr) to vertical stringing (44.3gr), and grouped around 1-1.1 MOA. From the target picture, 43.5gr and 45.1gr (the low and high of my charge weights tested) had the highest SDs of 19.7 and 13.6, respectively, yet had the tightest groups (0.61MOA and 0.72MOA, respectively). Could I get some collective help in interpreting this data and suggestions on where to focus next? [/QUOTE]
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Reloading
Need help interpreting OCW development for 308 Varget and 175 SMK
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