Compensating the wind when shooting with iron sights

Discussion in 'General Rifle Discussion' started by 11811O2, Jul 22, 2011.

  1. 11811O2

    11811O2 New Member

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    Hi guys.
    I'm new, so pray bear with me should I happen to misplace a thread or two.

    When I'm shooting (prone, 300m), I usually take my Schmidt-Rubin Infanteriegewehr Modell 1911 (for convenience's sake abbreviated to "L11").
    Solid Swiss rifle, straight-pull bolt action, 1'308mm of fun, shooting 7.5x55mm (GP11 / 7.5 Swiss), six rounds a mag.
    Easy to shoot, easy to care for, only half a downside I can think of (in non-combat marksmanship, that is): You cannot adjust the sights for wind.

    Which is what brings me here.
    As you can see, the sights can be adjusted but to distances and only between 300-2000m.
    Well, I said "half a downside". That is, because technically, you don't need to be able to adjust the sights.
    In a nutshell, you aim a tad off-target to allow for the wind to take care of the rest.
    Now I'm curious, though, how much, exactly, is a tad?

    Probably necessary stats:
    Distance to target: 300m
    Length of Barrel: 780mm
    Length of Drall: 270mm, right
    Muzzle Velocity: 760m/s
    Bullet Weight: 11.3-12.3g
    Angle to Wind: variable
    Strength of Wind: variable

    So, how would I go about working out the "tad"?

    Ps: Images not by me. I can, however, shoot and upload pretty
    much any angle and/or part with my not-so-good camera, if necessary.
     
  2. Wambli

    Wambli Member

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    A very important portion of the equation is your bullet's BC (ballistic coefficient). You can get those from the bullet manufacturers websites.

    Here you go:
    www.jacksonrifles.com/files/pejsa%20ballistics.xls

    You need Microsoft Excel (or the mobile versions that come with most smart phones) to run it. I have it downloaded in my Android phone and it works like a champ.
     

  3. jpattersonnh

    jpattersonnh Active Member

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    Practice. It is called Kentucky windage!
     
  4. HOSSFLY

    HOSSFLY New Member

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    Bout it -
    Making things more complicated than need be is not a good thing IMHO :eek:
     
  5. dnthmn2004

    dnthmn2004 New Member

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    What I was going to say. :cool:
     
  6. c3shooter

    c3shooter Administrator Staff Member

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    Part of the training of a long range shooter is to "read the wind". What does a 5 mph wind look like? In regard to leaves, branches, smoke, tall grass, flags. A 10 mph? Is it blowing L to R, at angle, or towards you? Elevation is quickly adjustable, since at long range, a rifle with sights set to close range would block your view of the target completely with the raised muzzle. But you could hold 1-2 body widths of your target left/right and still SEE target. Known as "Kentucky windage"