Can't get my head around this

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by royinidaho, Jun 2, 2011.

  1. royinidaho

    royinidaho Writers Guild

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  2. lostart

    lostart Member

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    Think of the bullet as a top. When you spin a top it takes some time to level out and spin smoothly. The less mass of a bullet or a top the faster this happens...the more mass the longer it takes to level out. The same is true as the bullet or top looses speed.
     

  3. rscott5028

    rscott5028 Well-Known Member

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    Lostart,

    The top analogy sounds great. Except that the top never stabilizes in the same location/orientation because there are too many variables. Likewise, the bullet won't stabilize downrange such that it corrects for error that was previously induced.

    Why would a bullet that wobbles and yaws begin to home in on a given point of impact as it travels farther down range like a laser guided bomb?

    I beleive that those claiming to have observed this phenomenon have not proven it statistically and/or have not accurately accounted for why they shoot better at long range.

    I haven't read the McCoy book. But, I suspect it's being over-stated and/or taken out of context.

    Hopefully, Bryan Litz or someone knowledgeable will jump in.
     
  4. SBruce

    SBruce Well-Known Member

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    In my experiences, it only applies to measuring in moa. I've seen loads that shot 3/4 moa at 100yds be 1/2 moa at 300 and 400 yds.

    I don't see how the groups could actually get smaller though.? Unless, it's a parallax issue...? I am no expert, just passing on what I've seen with a couple of rifles.
     
    Last edited: Jun 3, 2011
  5. rscott5028

    rscott5028 Well-Known Member

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    I too have seen people shoot better MOA at longer ranges.

    Was it the bullet "going to sleep" or the shooter making a better effort?

    All of the experiences I've seen and heard have been statistically insignificant to say one way or the other.

    I have yet to see a study where someone proved this with good science.

    But, I'm keen to better understand how this could be.

    -- richard
     
  6. Dano1

    Dano1 Well-Known Member

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    Howdy Roy!

    I can't understand this either, I just figgure that if I can get the rifle shooting one hole groups at 100yds, It'll shoot just as well way out therE (considering I can hold still). So far It's worked out ok.

    Dan
     
  7. the444shooter

    the444shooter Well-Known Member

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    Haven't you guys seen the movie "Wanted?" It's all in how you bend the bullet's flight path--Angelina Jolie does a great job demonstrating it, albeit with a pistol.





    Sorry, nothing actually useful to contribute to this thread--just wanted to insert some humor--I too, have been perplexed about bullets "settling" down and grouping tighter at longer distances.
     
  8. rscott5028

    rscott5028 Well-Known Member

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    You jest. But, that's exactly what the proponents of this theory unknowngly advocate.

    Any wobble will simply decrease accuracy/consistency. Hence, group size will be inconsistent and therefore allowing some groups to be tighter as well as looser at any distance.

    All you have to do is draw it out on paper and trace the path of a bullet from a top view. Put a little wobble in your lines at the start. But once the bullet "goes to sleep", it will continue along that path in a straight line unless the wind, spin drift, or correolis moves it.

    I really need to buy Bryan Litz's book to see if he addresses the subject.

    Either that or contact Mythbusters.

    JMO
    -- richard
     
  9. lostart

    lostart Member

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    The federal government has done some testing on this theory. The fellas at Los Alamos have concluded that it holds true. I work with the former director for the labs there. Though I also have my doubts, I am, as usual inclined to take his word for it. Do I completely understand it? No.

    rscott, you make some good points. They are also some of the very same problems that I have with the theory.

    If I remember next week, Ill ask him to further explain the phenomenon and Ill get back with his answers.
     
  10. rscott5028

    rscott5028 Well-Known Member

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    I'll be keen to learn more.

    Preferably something where someone proves that a rifle is consistently 1 MOA at 100yds and .5 MOA at 500 yds using a statistically sound model.

    ... and, no fair misadjusting parallax like SBruce pointed out.

    All I've ever seen on the matter have been (a) theories, (b) analogies, (c) computer models written by someone with an agenda, and (d) annecdotal examples of instances where a smaller group occurred at a longer distance.

    I'm ready to eat crow. But, I'm not going to fold because someone has a fancy title. Show me something convincing.

    -- richard
     
  11. Mikecr

    Mikecr Well-Known Member

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    Litz/Berger did do a 'mythbuster' on the elliptical swerving notions. It only happens within feet of muzzle release and ain't causing decreasing moa, or anything else -decreasing.

    I am one of 'those shooters' who consistently shoot tighter grouping in moa with distance.
    I can't prove anything, but I believe it's scope parallax.
    This passes more tests..

    I also consistently shoot with scopes at 25x or higher, and I wear prescription glasses.
    Any gun I shoot tighter at distance with, holds growing moa(as expected) when my son shoots them.
    He has eagle eyes, perfect method, and is a far better 100-200yrd shooter than I. But I catch up by 500yds!

    I've thought about it alot. Notice while shooting through glasses that there is just this little tiny area on the edge of the shooting eye lens that has to be focused through. This area NEVER matches a center lens prescription. That may be significant. Also, setting parallax on a scope is much easier and precise with growing distance. Our brains adjust vision to focus even with a relatively bad parallax setting -up close. But at distance, anything other than dead on seems blurry and moves more with head movement.
    There is no band to play with at distance, that a brain could quickly adjust to.

    Anyway, it's my theory, but I cannot acquire a solution from local lens-flippers...
     
  12. Speedo

    Speedo Well-Known Member

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    Found on Youtube: [ame=http://www.youtube.com/watch?v=KH9SCbCBHaY&feature=related]YouTube - ‪Pitch, Yaw and bullet path‬‏[/ame]

    Gus
     
  13. Topshot

    Topshot Well-Known Member

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    There is a simple answer to this question = Parallax.
     
  14. Mikecr

    Mikecr Well-Known Member

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    Notice the bullet PATH immediately set off on an angle(moa), and never deviating from that angle. So the 'going to sleep' aspect of this does not steer the bullet back to original POA, or cause reducing moa of impacts down range.