ACCURACY-GROUP SIZE DIFFERENCE AND n

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joeb33050 posted this 01 May 2019

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, I’ll make some statements about VALID testing.

 

Nobody has tested or will test for accuracy differences less than 5%. We don’t know for sure that ANY change makes a <5% difference in group size. We’re 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 don’t know, fairly certainly, that ANY change makes a difference between 5% and 9%. We’re 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. That’s 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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45 2.1 posted this 01 May 2019

Joe stated:

"Nobody has tested or will test for accuracy differences less than 5%. We don’t know for sure that ANY change makes a <5% difference in group size."

There are some quite serious folks outside the CBA membership that have done the above Joe...... I'm one of them. Specifically the Z= 2.33  3%, 440 groups.................. There are several things I've never seen in print either here or in the Fouling Shot that should be pertinent to things you try to discuss. Your turn.

 

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John Alexander posted this 01 May 2019

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45 2.1 says: "There are several things I've never seen in print either here or in the Fouling Shot that should be pertinent to things you try to discuss. Your turn."

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Ah! The wondrously serious shooters who are above joining the CBA or sharing the news about their labors and their secrets. on our humble forum.  We hear about these mysterious folks from time to time. But we never hear anything useful from them -- just their condescending  statements of superiority. 

Apparently these superior beings are like the alchemist of old who kept their procedures a closely guarded secret so nobody else could profit. So we never see their amazing results here or in the Fouling Shot. Can we see them anywhere backed up by witnesses of their remarkable feats?

The keyboard is easy to master -- accurate cast bullet shooting not so much.

John

 

 

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45 2.1 posted this 01 May 2019

John, everyone is free to do as they please. You can mock or denigrate as you see fit, but it doesn't change what other folks have already done. Your statement above is not a real credit to you or the CBA. Most of these guys stay away from the internet because of things like that.......................

As for the information to do things like that, it is already in print as has been for a very long time. All you or anybody else has to do is understand what they meant and put it together so it works. That is something that most people have a problem with. You want proof of these things?..... most of them will invite you to their range and show you, but they are not interested in traveling to shoot a match or to demonstrate their prowess... it won't happen because they're not interested in it.

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John Alexander posted this 01 May 2019

45 2.1,

I am sorry if my response sounded like I was exasperated. That was because your one-upmanship posts are often exasperating and insulting. However, I should have been more careful with my wording and I apologize for the tone -- but not for the content.

I suspect you have a lot to offer to others on the forum, I have told you so, and asked you to contribute your knowledge. But your posts seem to usually say that you, or some non-CBA member somewhere, knows things we don't know but "should be pertinent to things you TRY to discuss". But you never tell us what these things are.

Implying that members of this forum are so ignorant that they can only TRY to discuss issues is pretty insulting.

I also don't buy your contention that these experts you allude to are too sensitive to survive the discussions on this forum. But if so the Fouling Shot is always looking for new articles.  Why are these guys keeping all their wisdom to themselves? We would like to learn from them. Nobody here thinks they know it all.

John

 

 

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45 2.1 posted this 02 May 2019

You have a PM.

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John Alexander posted this 02 May 2019

Joe,

To be sure I am reading your post right; when you say "Nobody has tested or will test for accuracy differences less than 5%. " Is this the same as saying nobody has tested for differences under 5% because it would take 79 5-shot groups with each of two loads to get to 95% confidence and 159 groups with each to achieve 99% confidence level?  And nobody has done that, or will do that, because it isn't worth it?

John

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joeb33050 posted this 02 May 2019

Yes

 

Joe,

To be sure I am reading your post right; when you say "Nobody has tested or will test for accuracy differences less than 5%. " Is this the same as saying nobody has tested for differences under 5% because it would take 79 5-shot groups with each of two loads to get to 95% confidence and 159 groups with each to achieve 99% confidence level?  And nobody has done that, or will do that, because it isn't worth it?

John

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Ken Campbell Iowa posted this 02 May 2019

to kinda re-enforce joeb and johna 'ss thoughts on the steep mountain of testing for that 2 or 4 percent of improvement.

when i was shooting 22rf bench, with very accurate ammo and rifles and indoor 50 yard range ... ... my little group of 2 or 3 obsessives went through at least 100,000 rounds of testing,  trying for that 3 per cent.

we never found anything that we hadn't already learned from talking to shooters at the matches:

bullets, barrels, bedding .... then do everything exactly the same way each shot.

*******************

these days, i like the simplicity of cast bullets in deer rifles::  a 8 inch group is bad, but tweak a few things and you get a 3 inch group .... after that, better get out joeb's chart, ( and buy some more primers ) because that mountain is going to get steeper ...

ken

 

 

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Squid Boy posted this 02 May 2019

This conversation reminds me of when I was drag racing. It was pretty easy to get within a half second of the National Record but as you shave off tenths and then hundredths the cost went up exponentially. Only the most dedicated were willing to put in the time and effort let alone the money to get there. I am one of those crazy people who looks for the perfect load combination and will likely be doing it forever. I came here to be with like minded people. Thanks, Squid Boy 

"Squid Pro Quo"

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RicinYakima posted this 03 May 2019

I am so sorry you are also inflected with this illness, too. There is not cure, I'm afraid.

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Squid Boy posted this 03 May 2019

Actually I am glad there is no cure. It is a life long pursuit of perfection and like they say, if it was easy, everyone would be doing it. Squid

"Squid Pro Quo"

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