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Thread: Does the Eley Lot Analyzer predict ammo performance in custom .22lr BR rifles?

  1. #21
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    I believe Eley grades the ammo by score (ISSF) of rounds tested rather than by 10 shot group sizes as to whether it is Tenex or Match.

  2. #22
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    Albert,
    Everything that you and Landy post is brilliant. And, I really appreciate your willingness to share. You two contribute immeasurably to these forums.
    But my poor little brain does get headaches just trying to understand it all.

    It seems to me that the inconsistency in results between the first and last groups fired could, at least theoretically, have four different causes. To wit:

    1. Eley’s test protocol (equipment, methodology, etc) is so inadequate or inconsistent that it cannot give repeatable results.

    2. Sample sizes are inadequate.

    3. The variation is simply a product of the order in which the shots are fired. I believe it was Landy who noted in a thread sometime ago, that extreme spreads of a series of groups can be significantly altered by the order in which the shots are fired.

    4. There is really no practical difference among tests. We are simply measuring too precisely. For example, if we measure the length of ten cartridges with a yardstick, we get the same measurement every time. If we measure the lengths with a micrometer, they will all vary. Is there really any significant difference to ARA shooters between a lot that will put 91% of its sample in a 0.2" circle and a lot that will put only 88% in?

    Or there is a significant probability that I shouldn't attempt to understand your threads and respond to them at 4 a.m.

    I would note that the two best lots of Tenex that I've ever shot (out of dozens and dozens) have been the two best lots I've seen on the Analyzer. The first of those lots, I purchased before the Analyzer was online. It shot amazingly well. The other lot, I bought because of it's Analyzer data.

    Hawkeye Wizard
    Last edited by Hawkeye Wizard; 10-23-2017 at 08:21 AM.

  3. Default

    I still think it should be looked at as a tool. A marketing tool to the greatest extent but that's not what I'm referring to. It has some correlation with lots I tested and the biggest surprise was that it showed that one of the best Match lots I ever had (2015 lot) should have been exactly that. Is it going to correlate exactly with what can and will be shot? I don't see how it can. Because either Eley ammo has degraded a bunch over the last few years or an ARA 2500 would just be the pure luck of which 25 bullets you pulled and shot for record. Nobody needs a bunch of analysis to see that. Just look at Eley's statistics. It would just be luck. But it's been done more than enough times to indicate it's not luck.

    The analyzer should be looked at as a tool and no more, but people will buy Eley blind based on it and that's what Eley wants. Eley looks at it as a marketing tool.

    You can get some ammo that will hit a dime all you want. Think about that. They only say you could hit a dime 100% of the time on really good ammo. Not dead center the dime, just hit it. Just nicking the edge of it is about a .700" center to center group. I wouldn't want ammo that would produce only dime sized groups and certainly I wouldn't want ammo only capable of nicking the edge of a dime, but how many times have you seen that iconic picture of a group with a dime beside it for perspective? So, iIt might impress some people that you could hit a dime 100% of the time.

    So for people who get off on analyzing the analyzer do whatever floats you boat the highest. I think most people see it for what it is, but it will sell some ammo.
    Last edited by wsmallwood; 10-23-2017 at 08:10 AM.

  4. Default

    I appreciate your kind words.

    I don't believe shot order plays a role in this analysis. Once I had the data entered into Excel, a wide variety of comparisons was possible. For example, I compared average group size of groups 1 and 3 to groups 2 and 4 as well as a bunch of other combinations. I also looked for correlations between the average of all the groups for one barrel to all the groups in each of the others. The conclusion was always the same. I saw little of use.

    Yes, the difference between 91% and 88% is significant, and neither is sufficient to score well. As I mentioned, at 50 yards, an aggregate of 2200 requires 95% of impacts to be within 0.2 inch. For 2300 that number increases to 98%. Adjusted to measuring at 50 meters, the corresponding numbers are 92% and 96%. The difference may not be significant for other disciplines.

    Thanks.
    Albert

    Quote Originally Posted by Hawkeye Wizard View Post
    Albert,
    Everything that you and Landy post is brilliant. And, I really appreciate your willingness to share. You two contribute immeasurably to these forums.
    But my poor little brain does get headaches just trying to understand it all.

    It seems to me that the inconsistency in results between the first and last groups fired could, at least theoretically, have four different causes. To wit:

    1. Eley’s test protocol (equipment, methodology, etc) is so inadequate or inconsistent that it cannot give repeatable results.

    2. Sample sizes are inadequate.

    3. The variation is simply a product of the order in which the shots are fired. I believe it was Landy who noted in a thread sometime ago, that extreme spreads of a series of groups can be significantly altered by the order in which the shots are fired.

    4. There is really no practical difference among tests. We are simply measuring too precisely. For example, if we measure the length of ten cartridges with a yardstick, we get the same measurement every time. If we measure the lengths with a micrometer, they will all vary. Is there really any significant difference to ARA shooters between a lot that will put 91% of its sample in a 0.2" circle and a lot that will put only 88% in?

    Or there is a significant probability that I shouldn't attempt to understand your threads and respond to them at 4 a.m.

    I would note that the two best lots of Tenex that I've ever shot (out of dozens and dozens) have been the two best lots I've seen on the Analyzer. The first of those lots, I purchased before the Analyzer was online. It shot amazingly well. The other lot, I bought because of it's Analyzer data.

    Hawkeye Wizard
    Last edited by ahighe; 10-23-2017 at 11:54 AM.

  5. #25
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    Quote Originally Posted by jerry h View Post
    I believe Eley grades the ammo by score (ISSF) of rounds tested rather than by 10 shot group sizes as to whether it is Tenex or Match.
    Jerry,

    Eley does pump out a bunch of literature where 10-shot group ES's and ISSF scores are mentioned quite often, but I suspect they do that because they are the metrics that most shooters are familiar with, especially so for European shooters.

    I find it doubtful they'd ever use something like 10-shot groups as a metric for evaluating performance because 10-shot groups have a much poorer statistical correlation to precision, and I feel the same about ISSF scores, although to a lesser degree because that particular target does lend itself to that usage since the decimal scoring rings are fairly small for better resolution and the radius of each scoring ring increases by the same amount.

    Eley has also mentioned they use a statistical process quite often in their literature and webinars, so they should be very familiar with those metrics for performance that have the highest correlation to precision. That means it's highly probable they use something like MR (Mean Radius), RSD (Radial Standard Deviation), etc........for their in-house QC and ammunition grading.

    Landy

  6. #26
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    Quote Originally Posted by Hawkeye Wizard View Post
    Albert,
    Everything that you and Landy post is brilliant. And, I really appreciate your willingness to share. You two contribute immeasurably to these forums.
    But my poor little brain does get headaches just trying to understand it all.

    It seems to me that the inconsistency in results between the first and last groups fired could, at least theoretically, have four different causes. To wit:

    1. Eley’s test protocol (equipment, methodology, etc) is so inadequate or inconsistent that it cannot give repeatable results.

    2. Sample sizes are inadequate.

    3. The variation is simply a product of the order in which the shots are fired. I believe it was Landy who noted in a thread sometime ago, that extreme spreads of a series of groups can be significantly altered by the order in which the shots are fired.

    4. There is really no practical difference among tests. We are simply measuring too precisely. For example, if we measure the length of ten cartridges with a yardstick, we get the same measurement every time. If we measure the lengths with a micrometer, they will all vary. Is there really any significant difference to ARA shooters between a lot that will put 91% of its sample in a 0.2" circle and a lot that will put only 88% in?

    Or there is a significant probability that I shouldn't attempt to understand your threads and respond to them at 4 a.m.

    I would note that the two best lots of Tenex that I've ever shot (out of dozens and dozens) have been the two best lots I've seen on the Analyzer. The first of those lots, I purchased before the Analyzer was online. It shot amazingly well. The other lot, I bought because of it's Analyzer data.

    Hawkeye Wizard
    Hey Ron,

    You were up way to early and might want to consider taking a nap today. LOL

    Your point #2: "Sample sizes are inadequate."

    Yup, IMHO and in all the available material I've seen on the subject, you can't detect the small differences that are so important to us with only 40 rds in a Service Center or even the 200 rds Eley uses thru their test barrels in grading the ammo.
    However, in Eley's defense, where do you draw the line? It's simply not practical to shoot bricks of ammo when lot testing or grading for either Eley or the individual shooter.

    In addition, I would point out that even with my skepticism I still consider the Service Centers to be a valuable tool because it appears with the data I have you'll be able to weed out the really poor shooting lots and if you're close to the records at most Service Centers you stand a pretty fair chance of selecting a great lot.

    Thanks to a whole bunch of you guys sending me data from your testing at both Eley and Lapua for several years, and Dan as well as others identifying those rifles that end up as hummers....that's the trend I appear to see even though I can't prove it's true at this time.

    Remember also, not all of this selection process is driven solely by the ammo and I believe it's possible that an equal component of a great shooting rifle is probably the barrel or another unknown characteristic yet to be identified.

    I would be remiss if I didn't also point out that the average or beginning shooter, and more than a few experienced shooters, don't have the resources or time to test on their own and quite frankly do a very poor job of decision making in the process.
    For those shooters, and they're probably the majority, I believe the Service Centers are a viable option and perhaps a better one than what they're currently doing.

    I hope some of you are already aware of some of things I've said after reading Albert's articles in the last year but I suspect most of you won't be changing your minds based on anything Albert and I might say.
    BTW, any disagreement or non-belief is fine with me and I'm fairly sure it's fine with Albert. I'd like to think our sole purpose in dealing with these issues is to present the data and hopefully some of you will be curious enough to question it or research it farther on your own.

    Point #3: "Variation is simply a product of the order in which the shots are fired."

    I don't remember saying that but it wouldn't surprise me in the least if I did. In any event, it deserves some clarification.

    In so far as every rd you pull from the box will land in a different location due to the ammo's QC, the firearm shooting it, changing environmental conditions, and a 100 other variables....it's only natural for the sizes of a series of groups to vary depending on which rd you happened to pull from the box and which group it was fired into.
    If the QC process isn't used throughout the manufacturing of a lot, it may be true that the end of a lot shoots differently than the beginning or middle of the same lot, and that would be a component that affects the statistics and subsequent analysis.

    Fact is, it's an incredibly abnormal if not entirely impossible scenario when all the groups and targets you shoot are of the same size or same score!

    In the case of 5-shot groups and only 5-shot groups, one means of expressing that variation is with the use of COV (Coefficient of Variation) and that number is 25%. That number which is simply the Standard Deviation divided by the Average group size, changes based on the number of shots in each group and it means that "on average" every group you shoot will vary by 25% from one to another. Now if you only shoot a few groups, chances are the COV could be either much higher or much lower, but it narrows down to 25% as you continue to gather data.

    Just for a comparison, the COV of 2-shot groups is 50%.

    Landy

    I did this kind of hurriedly so let me know how many mistakes I may have made.

  7. Default

    Quote Originally Posted by ahighe View Post
    Hi Marty,
    Excellent question!
    I had forgotten about that article.

    I assume you are referring to the specification for the percentage of 10-shot reference groups whose size is less than 15 mm at 50 meters. The article reported that current (as of Jan, 2011) Eley TenEx Ultimate EPS ammo averaged 50 percent.

    Because averaging the Analyzer-supplied group sizes is tedious, I’ve calculated them for 26 Tenex lots so far. Only three (12%) met the specification of 15 mm if measured center-to-center. The average outside-to-outside group size for those same 26 lots was 0.885 inch (22.6 mm).

    I hope my math is wrong, or they used higher-quality barrels for previous testing, because the performance doesn't appear to meet their former levels.

    Albert
    Albert, thank you. marty

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