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Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
# of Shots per Group and MOA - Results
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<blockquote data-quote="speedengineer" data-source="post: 1941962" data-attributes="member: 112986"><p>Yeah...I've never done a ladder test, mostly because I don't want to waste the time and ammunition. I think many people have tackled this topic already. The idea of looking for a velocity plateau of a few fps (using a 1-shot ladder test) when your standard deviation of velocity is of similar or larger magnitude is silly. </p><p></p><p>I'm not interested in doing a full statistical analysis, but this graph took only a couple minutes in excel. It just applies some random velocity variation to a nominal velocity vs charge weight profile (linear) by using a normal distribution with a specified standard deviation. The point is just to visually indicate how much noise one would expect to see in any given 1-shot per charge ladder test. It's repeated 5 times, a through e.</p><p></p><p>[ATTACH=full]203617[/ATTACH]</p><p>^ Line "e" looks like a real swet spot around 57gn! ...Oh wait, that's just noise. <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite2" alt=";)" title="Wink ;)" loading="lazy" data-shortname=";)" /></p><p></p><p>[ATTACH=full]203618[/ATTACH]</p><p></p><p>I'd guess that one would probably need to have an SD of around 2 fps or less for this type of test to have any reliability. </p><p></p><p>I once searched the internet really hard to find someone who had performed a 1-shot ladder test twice in a row, to see if they got a similar result the second time as they did the first. I wasn't able to find anyone who had shared such info. And, I bet even if someone out there did get two tests in a row to agree on a plateau, a third test likely would not!</p></blockquote><p></p>
[QUOTE="speedengineer, post: 1941962, member: 112986"] Yeah...I've never done a ladder test, mostly because I don't want to waste the time and ammunition. I think many people have tackled this topic already. The idea of looking for a velocity plateau of a few fps (using a 1-shot ladder test) when your standard deviation of velocity is of similar or larger magnitude is silly. I'm not interested in doing a full statistical analysis, but this graph took only a couple minutes in excel. It just applies some random velocity variation to a nominal velocity vs charge weight profile (linear) by using a normal distribution with a specified standard deviation. The point is just to visually indicate how much noise one would expect to see in any given 1-shot per charge ladder test. It's repeated 5 times, a through e. [ATTACH type="full" alt="laddertest_SD10.PNG"]203617[/ATTACH] ^ Line "e" looks like a real swet spot around 57gn! ...Oh wait, that's just noise. ;) [ATTACH type="full" alt="laddertest_SD5.PNG"]203618[/ATTACH] I'd guess that one would probably need to have an SD of around 2 fps or less for this type of test to have any reliability. I once searched the internet really hard to find someone who had performed a 1-shot ladder test twice in a row, to see if they got a similar result the second time as they did the first. I wasn't able to find anyone who had shared such info. And, I bet even if someone out there did get two tests in a row to agree on a plateau, a third test likely would not! [/QUOTE]
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# of Shots per Group and MOA - Results
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