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A replication of the Federal Paper reload test

Discussion in 'Shooting Related Threads' started by Neil Winston, Feb 6, 2013.

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  1. Neil Winston

    Neil Winston Well-Known Member

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    I’ve admired some of the photos here of just how far you can push reloading a hull and some of the speed data interested me as well. But I feel I have to say something about “N=1” testing. That notation, “N=1,” means that these are “single subject” experiments.

    Such experiments may extremely limited in the extent to which the results can be generalized to apparently similar situations. In the case of multiple-reloading data, I advise readers here to consider each case a solitary example, maybe the only such result in the world, and take speculation no farther. Don’t, for example, consider it “demonstrated” that Hull X survives more reloads than Hull Y. You have only seen one of each and –this is the point – you have no idea if the examples you have seen are typical of the two kinds of hulls at all. You may have been shown, by chance, the best-ever example of one and the worst-ever example of the other and the only way you will know is to see more hulls tested.

    There was a recently-posted test of the longevity of a Federal Paper hull. It looked like a once-in-a-lifetime result and I didn’t want readers here to go away with a negative attitude toward the shells I myself shoot. You may remember it. I’ve re-graphed the result based on data from a graph of the results on this site.

    [​IMG]


    I decided to replicate that experiment as best I could with components on hand. I used 18.0 grains of Red Dot as dropped by an RCBS scale/dispenser combo. I used Federal 12S3 wads, Federal 209a primers, and put the shells together on a single-stage MEC, the perfect tool for this sort of thing. I used six shells since they fit so nicely into the six compartments of the small Frabill tackle box I used to keep the hulls straight.

    The chronograph is an inductive Oehler Model 84. Let me introduce you to its data sheets. The top third are the conditions, components, and so on. The middle third are the individual shots: their velocity, peak pressure, and the rise time of that pressure.

    Below that is the summary for this test, standard chronograph variables: Average speed, the standard deviation of the speeds, the high and low rounds, and the extreme spread. To the right of the speeds are the same summary statistics for peak pressure and rise time.

    Here are the shells I emptied to get hulls for the experiment.

    [​IMG]


    And the first reloads.

    [​IMG]


    The factories are a little faster, but the SD’d are similar, 7 and 9, and the extreme spreads are the same, 21 fps. It’s clear that for first reload you can duplicate factory speed performance, though the reload pressures are a bit more variable, with an SD of four compared to the factory’s remarkable two.

    But those non-zero SD’s and extreme spreads are a warning that single shell (N=1) tests are certain to provide less “representative” results than tests with more shells.

    Those results are always full of variability, no matter whether they are factory or reloads. Here are the raw data which will need some cleaning up before we can see the detail of what’s happening. Notice that every hull shows dips and rises in its slow trek to slower speed, but in the end they all get about as close to each other as they started out.

    [​IMG]


    All those lines just confuse things and we aren’t really interested much in the speed history of a single hull but rather in all of them. The following is probably the best way to present the two salient variables of multi-reload testing, where the speeds are headed and how consistent are the results. Let’s lose the lines connection adjacent data points and . . . here we have it, the results of the whole experiment which can be taken in all at once.

    [​IMG]


    The mean is another way to summarize data, but it can’t show variability in the way that graph does. But if we are going to compare these results and the TS.com data, it’s what we have to use. The beginning speeds are a little different but adding 24 (correction: 34, cited later in the thread) to all my data points gives us even starting points and here are the results of the test:

    [​IMG]


    As I suspected, the result of the test I saw here are in no way representative of the performance of Federal Papers in general when loaded with appropriate components. This illustrates the truth of my warning about single-subject experiments. Your subject may be an oddity and without more data to study you will never know it.

    This goes for all kinds of gun testing of course. People who shoot a pattern or two with this gun or choke tube or shell and think they can meaningfully compare it with equally carelessly obtained data from a different setup are deluding themselves. If some information is worth finding out, then it’s worth the expending the effort to get it right. Otherwise why bother to do it?

    Neil
     
  2. Scott Johnson

    Scott Johnson Well-Known Member

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    Neil "wizard" Winston excellant info and break down as expected, thank you, very interesting. Scott
     
  3. Barry C. Roach

    Barry C. Roach Well-Known Member

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    Impressive ....... but not as much fun.
     
  4. CharlesK80

    CharlesK80 Member

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    Neil, there you go again. We love it. Throwing cold water on an effort to show a trend.

    Well, you are like correct in your conclusion that the contested sample was very limited. And probably not available for retesting. But it is like winter... and the photos were very interesting... and we like to see individual efforts...and we can’t like shot outside...and the photos were really like interesting... and it is on a subject we all have some first hand knowledge, abet not as like precise.

    So, thanks to both posters. We do learn from them.
     
  5. Johnny

    Johnny Well-Known Member

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    MIA, Actually, we don't know Neil's 6 hulls are representative unless the experiment is repeatable.

    Your "one and done" rule is not valid at all. One pattern is never representative. Didn't we argue that point a year ago when Neil was absent.
     
  6. Bob Butler

    Bob Butler Active Member

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    Why does the red line on the last chart labeled- equalized average -have an 1160 fps when both scattergram charts above it show the tenth reload at about an 1130 fps for the average?
    Loads 8 and 10 both have results in the 1120 fps area.
     
  7. Joe Smoke

    Joe Smoke Member

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    Excellent work both researchers. Really makes me think, and will probably be thinking about this on the line as I pull the Fed paper from my shell box and insert it into the gun. I will be visualizing Neil's charts.....instead of thinking of nothing....

    Seriously, I will probably cull a little sooner now that I know the velocity tends to decrease. It also explains why I have noticed some variability in my chrono, as I have not been particular with using just once fired for my tests.

    Joe
     
  8. gdbabin

    gdbabin TS Member

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    The original intent I believe was merely a demonstration to show how far one could go reloading a hull multiple times. I don't remember any attempt by the ORIGINATOR to draw conclusions.


    Neil's approach is much more scientific. Expanding on his testing methodology would begin to produce reliable data that could be used to draw informed conclusions.


    I like both pictures and Excel generated graphs--but I really prefer pictures...




    Guy B.
     
  9. hmb

    hmb Well-Known Member

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    Reloaded Federal Papers smell good, what else do you need to know? HMB
     
  10. Neil Winston

    Neil Winston Well-Known Member

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    Bob (Butler) you are correct. Above I wrote "24" when the correct number was "34".

    I probably skipped over that a little too rapidly anyway; here's the complete story.

    [​IMG]

    Neil
     
  11. kenf

    kenf Active Member

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    Great stuff Neil- this stuff should really be stickied at the top of the forum.
     
  12. APrice

    APrice Active Member

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    BYG's tests (with photos) were very interesting and informative. To point out the obvious flaw(s) and try to paint it as a useless experiment in a "scientific" sense is small-minded at best.

    I'd guess that almost without exception everyone who posts here and reloads will continue to do what they always have...load a hull until it fails in some small way or just gets ratty looking.

    The biggest surprise to me was how far you could actually push the reloading process. The last thing on my mind was how all that was going to look on a graph.
     
  13. bkt514

    bkt514 Active Member

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    Find this kind of work very interesting, and would probably have some fun doing it myself, if I had the equipment. It lends some credance to what we often visually see when we go to do another reload of an empty (ie...check over the empty hull for flaws). Conclusion for my simple mind is....after 3 or maybe 4 reloads the empty hull should be chucked!! HEY...what smells better in a paper reload........Red Dot or Green Dot??
     
  14. Trap2

    Trap2 Well-Known Member

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    Uh Oh....
     
  15. Beretta Young Gun

    Beretta Young Gun Active Member

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    Neil, good data and graph. I was in no way trying to disprove that paper hulls are a good hull. I reload a lot of them and will continue to load them. I was wrong in testing only 1 hull as that 1 hull could have been defective from the factory. I really wasn't trying to be scientific in my approach I just wanted to see how far you could puch a hull. There are 10,000 variables that alter the results of a shotgun experiment from the batch of powder to the chrono its self. If you were to conduct this test again the results may vary drastically. I was not trying to say 1 type of hull was better than another I was just satisfying my curiousity. Again nice work. BYG
     
  16. Scott Johnson

    Scott Johnson Well-Known Member

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    BYG and Neil,
    Both of you, thanks, Great info and great job by both. Very interesting and its better than reading negative stuff or personal attacks. Thank you guys for making us think and ponder. Scott
     
  17. BigM-Perazzi

    BigM-Perazzi Well-Known Member

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    Neil, ever thought of taking up ice fishing???
     
  18. Scott Johnson

    Scott Johnson Well-Known Member

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    If he did he would probably break all the Minnedamsota records..........Scott
     
  19. Avaldes

    Avaldes Well-Known Member

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    Good stuff. I am glad that there was an interesting shooting related thread this early in the year!!
     
  20. Bob Butler

    Bob Butler Active Member

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    Neil,
    second question. How come you tested 6 starting at 1175 fps instead of the 1200 fps of the single hull test?
    Would seem to me that the data would be more comparable if the original speed of reload #1 matched the single hull test starting velocity.

    I am wondering now if the results of a 6 hull test started out at a higher speed would have any effect on the shape of the average results by load 10 due to the higher pressure and its effect on the hull.

    I think it is important to keep the FPS scale on the charts the same when presenting data as well.
    Makes for a better evaluation.

    I don't own a pressure set up and my Chrony is not that accurate. But I am a curious reloader. I see from this the value in shooting factory or once fired for when the score really counts.

    In the end does 40 fps matter, or a hundred?


    Bob
     
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