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If you are deeply interested in patterns, read Dr. Andrew C. Jones's book, "Sporting Shotgun Performance - Measurement, Analysis, Optimisation." Dr. Jones deals with statistically viable data. Data is obtained by feeding a computer program digital photos of patterns. One of the most enlightening findings is that patterns have so much variability that one must have ten (10) patterns with the same factors to get reliable data. This sort of data is capable of predicting "X" hits on a target at given range. Now that is a true prediction of performance.

Rifle fire uses the same type of statistics. Should you shoot 3 shot groups? 5? 10? How about 600! (sounds suspiciously like a shotgun pattern, no?)

I have no idea why O & T did all that work and then fell flat with their analysis.

DDA

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Don, to play the devil's advocate, do you have any idea why Jones fell upon the number 10?


"With one foot in the grave ..........and one foot on the pedal, I was born a Rebel" T.P.
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Yes, Stan. In statistics there are equations that predict how confident you may be in conclusions based on the variability of data and how much data you can gather. One such equation is "R-squared." It is a good predictor of how much data you need. For example, my little MOI machine has "R-squareds" of , usually, better than 99.9%. In said case, I would be safe with one data point. Note that the weight, balance, and MOI of any single gun does not vary. The only significant source of variability is bearing drag or weather vaneing in a strong air draft. With patterns there are many variables that may/may not be significant. I would take a SWAG that Jones used R-squared in his decision as to the number of data points required.

DDA

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That's about as good an answer as I can understand, Don. Thanks!


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IMO, a lot of misinformation has been passed to shooters over the years. O&T should have understood what was required for proper analysis. I guess they were unable/unwilling to invest the resources to do it manually, even with semi-slave student labor, like Jones and his trusty computer do it.

I'm aware of master barrel borers shooting patterns and "tinkering" with the choke until they got the pattern they/the customer desired. Never heard of anyone firing nine more patterns for verification.

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I have fired scores of patterns (not thousands) at paper and my grease plate over the last 40 years or so. I have never found the need for statistical analysis of shotgun patterns. Not saying there isn't a need, just that I have not had one. My main purposes for patterning a shotgun are:

1) to determine if a doublegun's patterns are regulated, and to determine to what extent they shoot to point of aim
2) to determine what load they are regulated for
3) to determine the approximate percentage of the pattern of a certain load

Beyond that it is is "too much sugar for a dime", for me. Once regulation is determined, and the best load for the gun and purpose, I just need to shoot it, because at that point I have confidence in the gun and load. And, it's hard to overstate the importance of that, IMO.


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#1, absolutely. #2 & 3, not, IMO. You are drawing a conclusion about a choke/load/distance/target area based on much too limited data. The ten patterns to draw valid conclusions still applies, IMO. Conclusions based on statistical unreliable data are, well, unreliable. IMO.

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How can you disagree with #2 and #3 Don, when they make no hard statement about any general principle? They are two of MY purposes for patterning a shotgun. If you read closely you will see that neither make a broad, sweeping statement about patterning, in any way. They are MY purposes. You may not agree with my reasoning for having these purposes, but you can't reasonably disagree with my opinions for myself. You can state that my principles are at fault, but my decisions on the level of accuracy necessary for me are mine. I have killed a limit of doves without a miss, a limit of 6 ducks with 6 shells, and have shot two 100/100 on sporting clays courses. Do I have to do each 10 times to have a valid statistical reference about my loads in each circumstance? I guess the answer may be "yes", and that without 10 replications it means nothing.

I just cannot see how determining the APPROXIMATE percentage of a load requires 10 shots, over 5? Remember, I said approximate. (The expectations here are the key. Actually, the expectations are the real reason for choosing 10 over other lesser numbers, are they not?)


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Re Dr. Jones, I recall that he came to some conclusions about skeet and single pellet breaks that, I think, pretty much surprised skeet shooters. Jones' analysis concludes that they're relatively common. Personally, that caused me to wonder whether maybe he needed to walk away from his computer, stroll around on a skeet field, and see how many unbroken targets he could find with holes in them. Plenty with one hole . . . some with even more than one. While his analysis might predict the likelihood of single pellet hits, can it predict the likelihood of single pellet breaks? The simple exercise of examining unbroken targets clearly shows that single pellet hits often fail to produce single pellet breaks.

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