Long Range Wind Drift.; Which Winds Have the Greatest Effect?

Discussion in 'Rifles, Bullets, Barrels & Ballistics' started by Bart B, Jan 29, 2006.

  1. Bart B

    Bart B Well-Known Member

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    This subject is often discussed among people who shoot at long range. It's about what crosswinds across the line of fire has the greatest effect on bullet drift; closest to the shooter, halfway or closest to the target. So let's read about what folks think. Here's the situation.....

    The target is 900 yards away. And there's three 10 mph 300-yard crosswind situations; each with the wind coming straight from the left or from 9-o'clock.

    First situation; an uprange 9-o'clock wind blowing across the line of fire between the muzzle and 300 yards. There is no wind between 300 yards and 900 yards.

    Second situation; a midrange 9-o'clock wind blowing across the line of fire between 300 and 600 yards. There is no wind between the muzzle and 300 yards and between 600 and 900 yards.

    Third situation; a downrange 9-o'clock wind blowing across the line of fire between 600 and 900 yards. There is no wind between the muzzle and 600 yards.

    There's three situations where the bullet goes through a 10 mph crosswind for 300 yards enroute to the 900-yard target. Which crosswind causes the greatest bullet drift at 900 yards; uprange (close or near wind), midrange (halfway) or downrange (furthest or far wind)?
     
  2. 4ked Horn

    4ked Horn Writers Guild

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    [​IMG]

    Thats how I understand it.
     

  3. jb1000br

    jb1000br Well-Known Member

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    4ky -- nice illustration...equal winds...closer they are to the the muzzle = more displacement on paper.

    JB
     
  4. 4ked Horn

    4ked Horn Writers Guild

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    Thank you. /ubbthreads/images/graemlins/smile.gif
     
  5. Fiftydriver

    Fiftydriver <strong>Official LRH Sponsor</strong>

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    While cross winds are the main issue, never forget updrafts and down drafts. If you shoot in an area with these you will learn quickly that they can leave you scratching your head in a big way!!

    Where I shoot LR, Lot of it is from one rim of a canyon to another. Up and down drafts are always an issue and can result in misses of several feet by these forces alone.

    Keep them in mind as well.

    Kirby Allen(50)
     
  6. Varmint Hunter

    Varmint Hunter Well-Known Member

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    I agree with the previous posters in that the wind at the muzzle would have the most impact on bullet deflection. However, the bullet, while traveling from 600-900yds has the longest time of flight and should, therefore, be more affected by the prevailing wind then the bullet during periods of shorter flight time. /ubbthreads/images/graemlins/crazy.gif /ubbthreads/images/graemlins/wink.gif /ubbthreads/images/graemlins/smirk.gif /ubbthreads/images/graemlins/tongue.gif /ubbthreads/images/graemlins/grin.gif
     
  7. 4ked Horn

    4ked Horn Writers Guild

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    Hair splitter. /ubbthreads/images/graemlins/wink.gif
     
  8. ss7mm

    ss7mm Writers Guild

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    What we need to remember is that the effect of wind on the bullet from the muzzle to 300 yards effects the bullet for the full 900 yards of flight. The bullet doesn't immediately go back to the line of sight when it passes 300 yards. It continues at the angle imparted by the wind from muzzle to 300 yards. The effect of the wind on the bullet from 600-900 effects it for only 300 yards, not 900 yards.

    I'd also go with the opinions that it makes more difference from muzzle to 300 yards.
     
  9. Shawn Carlock

    Shawn Carlock Sponsor

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    The slightly longer exposure to the wind does effect the bullet more in its given window of 300 yards (slightly) but the bullet shot in the muzzle to 300 yard wind will be effected the most by a good margin. 4kd's illistration is spot on.
     
  10. bailey1474

    bailey1474 <strong>SPONSOR</strong>

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    Gotta agree w/everyone else. 4kie, I do like the illustration. With all the praise your getting on this thread, your hat may not fit tomorrw /ubbthreads/images/graemlins/blush.gif!!!
     
  11. 4ked Horn

    4ked Horn Writers Guild

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    I do appreciate the kudos from you and Shawn and all the others before. I wasn't going for praise but I'll take it any way I can get it. I just figured that a picture is worth a thousand words.

    Besides I like pictures. Even if I gotta make 'em myself. They are often more clear than words.
     
  12. redbone

    redbone Well-Known Member

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    Looks good
     
  13. Mysticplayer

    Mysticplayer Writers Guild

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    Nice wind pic. I agree IF wind speed and basic direction is equal, the wind at the beginning has the greatest effect.

    But as Kirby said, I have shot out to 1000m in competition where updrafts and downdrafts, side winds at various distances have had varying effects. The wind at the bench was the least important.

    So, take that sighter shot if you can especially if hunting in new terrain.

    Jerry