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"The Effect of a Shot String" by Ed Lowry

Discussion in 'Shooting Related Threads' started by Neil Winston, Mar 21, 2009.

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  1. Neil Winston

    Neil Winston Well-Known Member

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    It's 30 years old, but it remains the last word. If you want to know about shot strings it's all here.

    It's pretty tough going in places, but I hope you will come away with

    1. How he did his tests

    2. The "cylinder of candidate pellets" which is a huge restriction on what shot string can do.

    3. Give some time to the shot string factor and see that the minor effect you get from the cited example table B depends on a crossing target at 70 fps. In the trap situation the crossing speed is a tiny fraction of that, leading to table B results that are so small you can discount shot string entirely, _including_ as an explanation for putative superiority of light loads.

    If you don't want to slog through the whole thing, you can just read the last two sentences.

    ". . . Burrard's conclusion that the practical effects of shotstring are very slight. The best evidence is that Burrard was right."

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    Neil
     
  2. crusha

    crusha TS Member

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    Thank God _somebody_ still has a brain...
     
  3. Neil Winston

    Neil Winston Well-Known Member

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    Anyone? Anyone?

    Neil
     
  4. hmb

    hmb Well-Known Member

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    Voodoo science. The only thing that allows a verifiable and accurate evaluation is shooting at a clay target and visually evaluating the hit. HMB
     
  5. Neil Winston

    Neil Winston Well-Known Member

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    Grrrrrr...

    Neil
     
  6. hmb

    hmb Well-Known Member

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    Good morning Neil, I thought that would wake you up. HMB
     
  7. Neil Winston

    Neil Winston Well-Known Member

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    Though I'll take your post as a joke, hmb, it does represent a common point of view here on TS.com, the aggressively "know-nothing" rejection of anything that smacks of science, mental effort, data, or what could be generally called ballistic "real life."

    It's a bad sign that about any fanciful shotstring claim will mop up responses in triplicate but the "real thing" appears to generate no interest at all.

    Neil
     
  8. WarEagle2017

    WarEagle2017 Active Member

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    Niel what is that BOOGER doing on the last pic.. LOL
     
  9. hmb

    hmb Well-Known Member

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    You're right, we are caught between, the seeing is believing, and the proof is in the pudding, believers. HMB
     
  10. Carol Lister

    Carol Lister TS Member

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    I'll never understand the need/ urge/ tendency to over-analyze and over-complicate things over which one has so little control such as the random distribution of the pellets in a shotgun pattern.

    Scientific analysis/ speculation won't change the basics: point the barrel at the proper place, keep it moving, pull the trigger and the target breaks! And that is especially true when the results of the analysis/ speculation is... "it really doesn't matter".

    Carol Lister
     
  11. Neil Winston

    Neil Winston Well-Known Member

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    Carol, the point of Ed's article is _not_ to complicate things, but rather to simplify them. It sweeps away all the nonsense about shotstrings and any arguments based on them and lets us look at two-dimensional patterns without worrying about the next response which will usually be that "patterns don't mean anything because they don't take shotstring into account." The proof he provides is that such comments are simply wrong.

    Nor is this "speculation." Mr. Lowry was the head ballistician for WW for decades and added immeasurably to what we know about shotshells. These are facts and to call them speculation is a perfect example of the "know-nothing" attitude so prevalent here.

    It's not even true that one has "little control such as the random distribution of the pellets in a shotgun pattern." Chokes can be changed, shot-size varied, shot-weight manipulated. Some of these changes will have an effect on scores, and if you want the best scores you can get you can benefit from analyzing what's going on. It's fine to just point the gun but remember, you are shooting against people who not only point the gun as well as you, but also use added knowledge to make pointing the gun more likely to break a target. In the long run, I see no point in pretending that scores are all shooter and not a combination of shooter and ballistics.

    Neil
     
  12. rennerize

    rennerize Active Member

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    It's fine to just point the gun but remember, you are shooting against people who not only point the gun as well as you, but also use added knowledge to make pointing the gun more likely to break a target. In the long run, I see no point in pretending that scores are all shooter and not a combination of shooter and ballistics.

    Neil

    Wow Neil you have hit the nail on the head again. I completely agree with this statement. I have tried to (and have helped) many shooters for over forty years and some that have nothing done to help their scores are still skeptical.

    Don
     
  13. chipking

    chipking TS Member

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    Thanks Neil and thanks to Ed

    --- Chip King ---
     
  14. Hap MecTweaks

    Hap MecTweaks Well-Known Member

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    Neil, notice the retained velocity of the buffered loads in table "C". I use to load quite a lot of buffered loads using data from my old loading manuals. Almost always, the velocities were lower from the beginning while chamber pressures would rise. Comparing the 1-1/4 ounce lead load to the 1-1/2 ounce buffered load says those buffered loads starts much faster? I found that odd because the 1-1/2 ounce buffered loads I've loaded were less velocity from the start?

    I've never put much faith in shot string length for success regardless of how rag writers contend they figured it all out. I do however believe that the smaller the payload the shorter the shot string length and the pellets pass through a target much sooner due to being shorter in length only.

    Hap
     
  15. gun fitter

    gun fitter TS Member

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    Neil I will agree with the data and I don't feel there is a lot of effect from shot string.

    I have to ask this question since it seems to be something of an effect. Will hitting an object with all the pellets at the same time have a more positive result? I really wonder?

    Now were getting in to pellet energy and target composition. If it takes 3 to 4 hits to break a target will two hits at the same time work?

    I have noticed that some chokes look similar on paper but seem to hit targets differently. Can you explain this?

    We all know that incoming targets break easier than outgoing targets.
    (at least all Sporting shooters)

    Could the elongation of time that the pellets strike an outgoing target effect this? If so than there would be an effect from shot string.

    Or is this simply the result of the pellets striking the clay at a higher velocity? I really want to know but I suspect it's a bit of both.

    Your thoughts?

    Joe
     
  16. welderman

    welderman TS Member

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    I agree that Lowry is brilliant. I also believe that after all the books that have been written and all the tests that have been performed, we don't really understand or agree on the ballistics of shot flight. If you think I'm wrong, go into any club and start a discussion on the subject. Being able to break every bird doesn't qualify one as a ballistics expert. The quest for knowledge may take us into new territory and I am personally interested to see where it leads. I am using high speed video, lasers, piezo-detectors, and a bunch of other high tech. devices to better understand the physics of shotshell flight. Giblin's work is the most recent publication I know of, and I think our video recordings have provided superior results. welderman (Tom S)
     
  17. just_bob

    just_bob Member

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    Neil,
    I for one thank you for all the effort you make to clarify these issues.
    I will no longer look to use the shot string to any advantage.
    It is obvious that it is a distinction without a real difference.

    Now 7-½ or 8???
    Well to each their own.

    Just_bob
     
  18. zzt

    zzt Well-Known Member

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    I'm just flabbergasted by this thread and what most of you are reading into it. Read the damn article again. It didn't say shot string didn't count. I'll grant you that for ATA targets you can disregard it. Geez, the maximum intersection angle for even a slow 27 yard shot on a 3-hole hard left is only 25 degrees. That's a going away shot in anyone's book. However, for the example given, if you don't want as much as you can get of the 4.8% PE you lost to the long shot string back, you are simply looney.

    Welderman, keep up the good work. When are the next pictures due?
     
  19. derbyacresbob

    derbyacresbob Well-Known Member

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    Why no mention of muzzle speed? Because muzzle speed has no effect on the pattern or shot string. The pellets all leave the barrel together inside the wad. The pellets do not spray side ways just because the barrel is moving.

    Shoot at rabbit targets on the ground and swing your muzzle as fast as you want and you will see a round pattern hitting the ground. Muzzle speed would change how far you need to lead the target though.

    I don't think targets that are flying at 40 mph fly into the side of shot strings very often when the shot strings are going 600 to 800 mph.
     
  20. welderman

    welderman TS Member

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    A simplified way of thinking about shot string is to answer this question. If you had to choose between a perfectly uniform pattern with all the shot arriving at the same time (no shot string) in a 30 inch circle, or a continuous line of pellets arriving one right behind the other spaced less than one inch apart (long shot string), which would you choose? Welderman (Tom S.)
     
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