Bullet drift question ? The yaw factor...

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by dustybrown, Feb 18, 2011.

  1. dustybrown

    dustybrown Well-Known Member

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    I noticed that my POI was lower today when I shot my 300 rum in the wind than when it was calm. The drop data for my load has been right on for along time. I've just never shot in such crapy conditions as I have today. It was blustery at best. When it was stable at around 15 mph I shot a 3 shot group. All LOW for my dope.

    My question is.... when a bullet is bucking a full value wind like it was today 15 mph plus is the YAW in the bullet killing some of the velocity because its not on a straight flight path as in a no wind or tail wind ???? Not as efficient yawed out ?

    Target was at 935 yards. My dope was 18.3 MOA up and I had about 7 moa left impact for a full value wind out of 9 oclock. I noticed my POI was a full MOA lower than the day before with no wind. Is my bullet actualy traveling further because its in a parabolic curve fighting the wind ????

    Any help would be great guys thanx....
     
  2. Scot E

    Scot E Well-Known Member

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    It likely had to do with how the wind was traveling along the terrain you were shooting in. Any wind can affect elevation up/down depending on how the wind is traveling along the terrain in between you and the target. Canyons, ravines etc can wreak havoc with elevation adjustment.
     
  3. SBruce

    SBruce Well-Known Member

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  4. bigngreen

    bigngreen Well-Known Member

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    A wind from 9 o clock will cause a low hit, as far as I understand it is the wind and the rotation of the bullet getting together to cause this, a 3 o clock wind causes a high POI.
    Boss Hoss sent me this to help with wind calls.
    [​IMG]
     
  5. Scot E

    Scot E Well-Known Member

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    I believe that chart is accurate for flat land use if I remember correctly. Varied terrain can have all kinds of additional affects as well.
     
  6. SBruce

    SBruce Well-Known Member

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    You are absolutely correct. Both charts are basically designed around flat ground shooting.
     
    Last edited: Feb 18, 2011
  7. dustybrown

    dustybrown Well-Known Member

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    Great info !!! thanx....
    just when ya think yer a shooter try some wind on for size....
    and yes the canyon I shoot across has some side draws .... posibly a down draft too? but I think its somthing to do with Speedys chart. thanx agian...