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colo native
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Re: ACCURACY-GROUP SIZE DIFFERENCE AND n
May 1st, 2019 at 3:34pm
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Hummmmmmm------------
  
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joeb33050
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Re: ACCURACY-GROUP SIZE DIFFERENCE AND n
Reply #1 - May 5th, 2019 at 6:28am
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ACCURACY-GROUP SIZE DIFFERENCE AND n
We want to know if two loads are different, if primer choice or bullet diameters or powder weights make an accuracy difference. This table shows the number of 5-shot groups that must be fired at various % of difference in group size and % sure of the difference.
Instead of just dumping the table here, Iíll make some statements about VALID testing.
Nobody has tested or will test for accuracy differences less than 5%. We donít know for sure that ANY change makes a <5% difference in group size. Weíre never going too know if shooting bullets in the order cast makes an accuracy difference.
Almost nobody has tested or will test for accuracy differences between 5% and 9%. We donít know, fairly certainly, that ANY change makes a difference between 5% and 9%. Weíre probably never going to know if indexing bullets makes an accuracy difference. 
As the difference increases to 10% and above, valid testing begins. We can see, fairly clearly, differences of 10% and above. Thatís the stuff that we know to be true. We know, with a great deal of certainty, that the Lyman 311/314299 bullet will shoot accurately in most rifles. 


  
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joeb33050
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Re: ACCURACY-GROUP SIZE DIFFERENCE AND n
Reply #2 - May 5th, 2019 at 6:29am
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Found and fixed an error.

joe b.
  
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Re: ACCURACY-GROUP SIZE DIFFERENCE AND n
Reply #3 - May 5th, 2019 at 12:19pm
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A question - how would the numbers change for larger number of shots, say 10 or 15 instead of 5?

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joeb33050
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Re: ACCURACY-GROUP SIZE DIFFERENCE AND n
Reply #4 - May 5th, 2019 at 1:27pm
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MikeK wrote on May 5th, 2019 at 12:19pm:
A question - how would the numbers change for larger number of shots, say 10 or 15 instead of 5?

Thanks.


For any % sure of the difference between loads, the % sure varies with the total number of shots.
Shoot 30 2-shot, 20 3-shot, 15 4-shot, 12 5-shot, 10 6-shot, 5 12-shot, 4 15-shot, 3 20-shot, 2 30 shot or 1 60-shot groups, and the result is the same % sure. But, any combination of total 70 shots and the % sure goes up; any combination of 50 shots and the % sure goes down.
In the long run.
  
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