Wind reading for +1K shots

Discussion in 'Extreme Long Range Hunting & Shooting (ELR)' started by Topshot, Aug 1, 2012.

  1. Topshot

    Topshot Well-Known Member

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    I thought I would open a thread on reading and dialling wind on ELR shots. This is a difficult skill and I am sure that their are different methods used. To start off, I will describe the method that I use.

    First up, if the wind is blowing strong, I do not shoot at game beyond 1K. Rocks etc are fine but for ELR shots at game I will only consider it with a light breeze or dead still conditions preferred. Experience has shown me that it is better to stay within my comfort zone when shooting at game.
    But when I do take an ELR shot in the wind I try and gather as much wind information as I can prior to taking the shot. This means taking wind readings at different locations on my way to the shooting location. It is amazing how much the wind strength changes just by moving around the side of a hill 20 or 30 yards. One side of the hill will be sheltered and only a short distance away on the other side of the hill the wind could be a lot stronger. What I am looking for is the maximum wind strength I can find and then looking at the trees etc at that location. I then use this as a reference for areas way out down range where I can see movement in the vegetation.
    While on flat country the cross wind can be quite consistent, in the hills it is very different. The wind strength mid way across a valley can easy be 1/3 or more higher than what the vegetation movement at ground level is telling you.
    I think of wind it as being similar to water flowing down a river. It is slower near the river bank and faster out near the middle where it is deeper. Canyons and valleys have the same effect on the wind. They also have a vertical component as the wind rises up and down the hill sides at an angle. The steepness on the terrain will indicate how much vertical you can expect. If the terrain has hills that have a 20% slope angle then it would be a fair bet to assume that their might also be a 20% vertical wind component as well.
    I sit and watch the effect that wind has on vegetation down range while glassing for game. I try and get the direction and strength while taking the topography into account.
    Where taking a practice shot, I put a lot of effort into working out the wind correction prior to taking the first shot. Then I look for the bullet splash and see how much I was off. With the information from the first shot I then take a long look at the wind and try and work out where I went wrong. This is how I learn from experience.
    If you practice at the same location a few times it gets quite easy to get the first shot very close to the target. On a new location it can be tricky. So when hunting it teaches you to be wary.
    My longest shot on game was at a locations where I had also practiced a few times. If I had not done this, I doubt I would have attempted the shot even though the wind appeared calm. Its those hidden breezes that can catch you out.
     
  2. bigbuck

    bigbuck Well-Known Member

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    Thanks for starting this thread . I know I will follow it along. I just started 1000 yard shooting and I am a beginner at wind reading . For the first time out I installed a ribben at the edge of my wooden target (plywood) and the wind was present the whole time . Now at first glance I couldnt see any wind activity but the ribben told me other wise. I know this is different from what you do but it has helped me to get it drilled into my mind that there is always going to be wind at 1 point or the other sometimes multiple wind conditiions.

    Great subject and thanks again for posting.......
     

  3. Broz

    Broz Well-Known Member

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    Good post Top Shot. You covered it pretty darn well. I will add a little of my own methods and indicators I look for other than the ones you listed and a little on how I see it.

    Verticle wind or as I call it "Lift" Pine trees are a great indicator. If they are moving and appear to be flapping their limbs like they are trying to fly but no left or right lean is obvious, that is lift. Most of the time shooting 1000 yards and on out to 2000 it will be from 1/2 moa to to 1 1/2 moa of lift. I usually go for a 1/2 to 3/4 moa on the turret and time the shot where the flapping is least.

    Morning light fog is the sweetest indicator. Like painting the wind. I have sit and watched it move for hours to learn what the terrain below does to it.

    Give me dead still light fog and I will have the confidence I want for that long shot on game.

    Here are a few pics of fog and wind currents.

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    If I am shooting aross a canyon I will be watching the very tip tops of trees between the gun and the target. That sprout going out the top of an everygreen tree is a great indicator for direction and speed. Plus they might be up where the bullet will arc depending on terrain.

    On game I will look for these small but important indicators. Breath steam from their nose for wind direction and speed. On antelope if you watch long enough, and if it is dry enough, one will move and leave a little dust off their feet. Small to look for, but a good indicator of direction of wind at the target.
    Also in some cases I have seen the long hair on the mane of an elk move too. If I see this there is a brisk wind at the target and I real in all the distance I can or pass.

    Wind at the rifle trumps all other. It starts the bullet off path first and that direction or path will be hard to over come by wind at the arc or at the target. It is a common mistake to let down range wind, even if a complete different direction, over rule all of the wind at the gun. So give the wind at the gun the most value. It is also common to want to underestimate the wind at the gun. As TopGun said, if you are shooting across a canyon you can bet it will be stronger in the middle. So don't be affraid to add a few MPH to the wind at the gun. I sometimes will double it depending on clues from other indicators.

    Mirage.... Not as easy to read as some like to talk. I go slightly off focus on the target and read it there. I also on some occations will pick a point 1/2 way to the target and go slightly off focus to get a reading of mid wind direction. But be careful here. I want to read the mirage in mid air. It will always look much faser off an object like a deadfall or a hot rock. So look above objects for a truer reading.

    My advice to beginners would be this. Use a quality wind meter like kestrel. Read the wind at the gun and go with the higher side of the reading to enter into your program. It will get you close and if it is a consistant wind will put you on.

    Wind Rules on long range shots. I do not in any way claim to have it mastered. But I practice alot and I have gotten much better. But, if the conditions are not good for the distance I real it in to where I am confident or I pass on game shots.

    I also do like Top Gun suggested. If I miss a rock I watch the splash if visable and try to learn what just happened. Plus I spend quite a bit of time in the spring shooting from my favorite vantage points for hunting. And I keep a good log.

    Jeff
     
  4. Boss Hoss

    Boss Hoss Well-Known Member

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    Read, Understand these instructions from one of the best shooters on the planet and you will be sucessful:

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  5. Topshot

    Topshot Well-Known Member

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    Boss Hoss,

    I think you need to resize your post as it is very large. You may also need permission from the author to reproduce it here.

    Also, humidity does not work as he described it. He is wrong!
     
  6. Broz

    Broz Well-Known Member

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    + 1 Please, :D
     
  7. Boss Hoss

    Boss Hoss Well-Known Member

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    Will pass you comments on to him when I speak with him later today but his comments will not be Top Shot----sorry but Speedy Gonzalez is a HOF BR shooter, has held several world records, ran the Brownells Gunsmith 3rd year school at Trinidad, author of countless articles on the subject of shooting, is one of my best friends and shooting partner. To put it bluntly he has forgotten more about the subject of accuracy and what it takes to shoot accurately, build the rifles and to design and make the bullets including the dies that make the bullets than most folks on the planet. Please post your response and it will be forwarded to Speedy. If you are correct it will be acknowledged.

    Will pass your comments on to him when I speak with him later today but his comments will not be printable lol.

    Am on the phone right now and read this to him and the part from the conversation that I can quote is “that’s ok that is why I do not post anything on those kinds of websites”.

    Also--the edit function is not showing up when I try and resize..
     
  8. bigngreen

    bigngreen Well-Known Member

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    I find the wind and learning how it moves through an area to be one of the things that I like about ELR shooting, it's something that the ballistics table won't tell you and your Kestrel may only give you hits of. I really like watching an area with a wind while snowing then during the spring shoot the area and evaluate what is influencing the wind path.

    One key thing clicked for me this spring in my shooting area and that was paying attention to the prevailing wind direction, we're sending bullets 100+ ft over the line of sight to the target and it's getting into air flows that are determined more by the natural air flow in the area vs the air that is more affected by the terrain.

    I've really had a hard time using trees as an indicator for wind, I think they are just to stiff in my area and if they are moving it's a wicked wind. I do use them a lot to listen for the wind velocity, you can really hear the wind coming up and down.
     
  9. Augustus

    Augustus Well-Known Member

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    Yep, he needs to re-visit his statement on humidity, bet it was a typo.
     
  10. Augustus

    Augustus Well-Known Member

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    Just playing with the Atrag, using inputs for a 175 SMK at 2650 there is only around one tenth of a mil difference in vertical drop at 1000 yds when comparing 10 percent vs 100 percent humidity. In the case of the 375 Cheytac it is barely measurable.

    If shooting a Rd with low velocity or very low BC the effects are much more pronounced.
     
  11. Topshot

    Topshot Well-Known Member

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    Boss Hoss,

    I make no derogatory statements about Mr Speedy Gonzalez ability as a shooter or his record in competition. He is obviously a well known a and respected shooter. However his statement on the effect of humidity is in error. Simple as that.

    This may be a typo or a misunderstanding of the facts, I don't know. He states that a 20% change in humidity will result in a 1 MOA change in point of impact. This is a vague statement as he does not define a distance that this 1 MOA change is made.

    In no way will a 20% change in humidity result in a 1 MOA change in POI at 100 yards or any distance under 1000 yards. In actual fact, the only change that I can find at 1000 yards is a mere 0.1 MOA. and that is in the opposite direction to what he states it will be.


    The effect of atmospheric conditions on a bullets trajectory is due to changes in air pressure, temperature and humidity. Variations in these three things, result in a change in air density and the speed of sound.

    While changes to air density have a large effect bullet drop, changes in the speed of sound have only a very minor effect on trajectory and mainly at extreme long range where the transonic barrier is encountered.

    A change of humidity from 0% to 100% at 59 degrees F, has only a 0.2% change in the speed of sound. So only a minor effect at best.

    Please read the effect on air density due to changes in humidity below and in the link provided, it helps describe why the effect on trajectory is opposite to what Mr Speedy states.

    The effect on air density can be read here..... Density of air - Wikipedia, the free encyclopedia
    But in short........ The addition of water vapor to air (making the air humid) reduces the density of the air, which may at first appear counter-intuitive.
    This occurs because the molecular mass of water (18 g/mol) is less than the molecular mass of dry air (around 29 g/mol). For any gas, at a given temperature and pressure, the number of molecules present is constant for a particular volume (see Avogadro's Law). So when water molecules (vapor) are added to a given volume of air, the dry air molecules must decrease by the same number, to keep the pressure or temperature from increasing. Hence the mass per unit volume of the gas (its density) decreases.

    A lot of the other tips that Mr Speedy gives sound like good advice. :)

     
  12. drbill

    drbill Well-Known Member

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    So if the elk I'm going to eat is standing by a range flag and that range flag is drooping a little more than the wind conditions appear to be and I'm a little more damp I should expect the bullet to be just a smiggen faster when it reaches my meal and therefore may not need to raise up on his chest as much (distance dependent). I believe Linda Miller mentions this in "The wind book for rifle shooters". The most "common" thing to think is the humidity will make the air "thicker". In reality it makes the air "thinner" (for reasons you just explained).

    Is that fair to say? or am I wrong?
     
    Last edited: Aug 6, 2012
  13. .30 CAL

    .30 CAL Well-Known Member

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    Is that fair to say? Or am I wrong? ? ? ?
    I don't think there is a right or wrong in shooting but more of an effective and not quite so effective approach. The statements made on humidity are also published in FM 23-10 HQ Dept of the Army 17 August 1994. But this thread isn't on humidity, so here's what I do for reading the wind:
    1. Set up wind flags at the bench, half way to the target, and at the target. I use these
    http://www.brflags.com/
    Extra large with HIVIS colors, obviously they don't go up hunting (not because that is ridiculous but because if don't camp where I plan to shoot from they will probably be stolen).
    2. Get a wind reading from the Kestral (I use the line it up to point of aim method and use the reading as a full right or left value).
    3. Observe nature from the muzzle to the target and decide if I need to make an additional correction (so far I have only corrected for wind at the gun) and apply this correction.
    4. Observe the wind flags I've set up because nature and the wind flags tell 2 very different stories (the flags are super sensitive).
    5. Get all dialed in and ready to pull the trigger.
    6. Start all over again because the condition has changed.
    7. Wait for the same condition because this wind reading is kicking my A$$ right now.
    8. Record my hit or miss and try to understand why I hit or missed.
     
  14. drbill

    drbill Well-Known Member

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    My comment was an attempt at humor and the "confirmation" of my understanding of humidity.:D I use Source for Super-Sized NRA Range Flags « Daily Bulletin from the Starr family atop 1.5 or 2 - 1 3/8" chain link top fence eye hooked t-posted in ground. $50 total or less when done. The difference in long range and ELR hunting has many factors that each of you have described and I am greatly thankful for your comments. Some individuals do not have/make a chance (but should for reasons explained) to visit their favorite hunting grounds in the off season to practice on "their" terrain. Snow at elevation, heck sometimes you have 80 degree days and no snow and maybe next year feet of snow. I can "see" each individuals "understanding" on this topic and its a good topic at that. I can see how practice at these locations will build the confidence of a shooter and of course keep ethics in check. As each year passes one would understand his hunting ground more and more and the increased ability for ELR in that area. Thank you.