Jeff_Schultz wrote on Sep 28
th, 2018 at 5:34pm:
joeb33050 wrote on Sep 28
th, 2018 at 11:21am:
I consider the NRA results to be suspect-perhaps false.
A mighty thin evidence.
It just got thicker
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That's complete nonsense! I just looked at the scores from the latest match in Camillus, NY from the J Louis post. 1st place was .209; 15th place was just over .3 and 29th place was just over .4. 1" + groups at 100 yds in IBS competition? It never happened.
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Yes, IBS 100 yard 5-shot groups >1" (almost) never happen, and 5 group aggs happen less often.
I never said that they do.
Years ago I made a computer model of group sizes; from 2 to 10 shots per group. This will simulate ex 200,000 5-shot groups.
Model + some algebra and I made a table of ratios, 2-10 shots per group, 2-10 groups per set.
To check the arithmetic and model, I kept records of largest group/smallest group in my shooting. My record avg looked like the model/algebra expected avg, so I figured the arithmetic was correct.
Then, lately, I checked CBA records for 3 years. Looked ok.
Data was scarce, so to American Rifleman, and NRA data looked very different. ?????????????////
Then to IBS data, looks like mine and CBA.
What we're measuring is largest group/smallest group in a set of groups, ex 1"/.5" = 2.00 in a set of 5 groups. We expect 1.91, get 2.00.
Mine, CBA and IBS suggest the arithmetic is correct, NRA is off and I can find no explanation.
There are no group sizes in the tables above.