wind(Mirage) vs. distance off ground Q???

Discussion in 'ELR, Ballistics & Bullets Board' started by Rem06, Feb 4, 2018.

  1. Rem06

    Rem06 Silver $$ Contributor

    Joined:
    Jun 21, 2006
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    i Suk at reading wind and Mirage, come ups are easier, L/R dope tough. I just read the short version of "Reading Mirage with Wind Effects" and will head to the full version soon.

    Q1. as short as i can put it, if i say/type it correct?

    is Mirage better farther off the ground?

    aka: belly on the ground, bench vs standing using tripod?

    farther off the ground better or worse? say off the edge of a cliff over a ravine shooting at a mountain goat?

    mirage/wind?

    "A condition of cool air overlaying warm air next to the ground is the cause of heat waves or mirage",

    thus and eliminating heat off the barrel?
     
  2. XTR

    XTR

    Joined:
    May 15, 2011
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    3,274
    What follows is my personal experience.

    I find mirage to a very good indicator up to about 8MPH. After that it starts getting really flat and flags become better. Above 12 MPH it's pretty much useless because it's just a flat layer on the ground, and flags, competitors hats, shooting mats etc become better indicators.

    It may just be that I am watching all the time and not shooting, but it seems that I can see mirage better from a chair than from the ground, but I think that's a perception that is skewed because I am in and out of the scope shooting as opposed to watching and reading when I am scoring or coaching.

    Mirage is easier to see over level-ish ground; e.g., some place like Oak Ridge where the line of sight is 40 feet off the ground at 600 yards is much harder to pick up the mirage than a range like Phoenix or Camp Perry where you are looking across a generally level field.

    In long strings of fire barrel heat will cause mirage that distorts your view of the targets. You don't see it if your scope is focused beyond 300 yards somewhere, but it makes everything more blurry. That is the reason for the mirage shields on most long range rifles in NRA competition. A breeze will blow it out of your view, some BR shooters use a small fan on the bench to blow it away to one side. Once on a calm afternoon I was shooting some velocity tests at 100 yards and I noticed the mirage curling up in the edges of the rifle scope. Only time I've ever been able to actually see the waves from the barrel, but you can tell the difference in your view at long range with and with out a mirage shield.
    .
     
  3. steve_podleski

    steve_podleski

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    The further the ground below the line of sight, the weaker the mirage since the ground heats the air.
     
    Canadian bushman likes this.
  4. Bart B.

    Bart B.

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