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Thread: Reading wind

  1. #21
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    Quote Originally Posted by Tatume View Post
    True.



    I'm not so sure. This is the topic of many heated discussions. Here is my opinion.

    First, many people, including some accomplished shooters, believe that the wind changes the direction in which the bullet travels. It doesn't. Side wind displaces the bullet sides ways, but the direction of travel is unchanged. Ask any pilot how the wind affects an airplane in flight. Imagine that you're flying in dead calm air and your direction of flight is directly towards your destination. Along the way you enter an area where there is a 10 mph wind at 90 degrees to your direction of flight, and you fly for one hour without making any correction. At the end of the hour you re-reenter dead calm air. You will miss your destination by 10 miles in the direction in which the wind blew. It doesn't matter if the side wind was near the destination or closer to the departure point.

    Second, a faster bullet will be affected by wind displacement less than a slower bullet. This is simply because the wind has more time to exert force on the slower bullet. By this logic, the wind down range has a greater effect than the wind near the firing line, because the bullet is slower down range.
    A bullet does not have an engine to maintain a constant speed so wind drift is similar to drop. It's a parabolic curve not a straight line. As the bullet slows the wind has longer to affect it's time of flight. The question that is highly debated is at what point are the effects of wind the greatest?

    The faster verse slower is only valid if it's the same bullet. I can push a 22 cal. 40 grain Nosler Ballistic tip at over 4,300 FPS yet it is not much of a 1,000-yard bullet compared to the 80 thru 95 grain bullets that start much slower.

    Some light reading here:

    https://apps.dtic.mil/sti/pdfs/ADA317305.pdf

    https://www.sierrabullets.com/exteri...ects-of-winds/

    https://www.premsvcs.com/post/the-ro...nd-bullet-drop

    https://www.tmtpages.com/windvector.htm

    https://www.thetruthaboutguns.com/ba...ginners-guide/
    Last edited by M-Tecs; 01-15-2025 at 01:18 AM.
    2nd Amendment of the U.S. Constitution. - "A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."

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  2. #22
    Boolit Grand Master

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    If you get the chance watch a 1000 yd match thru a spotting scope at about 600 yds from the target ( some days its much closer to you) you will see the trace and swear its going to hit 10-12 targets over, then the wind catches it and between drop and wind it looks like a banked curve the trace drops and swings back into the right target. As M-tecs said it is parabolic getting tighter and dropping faster as it nears the target. It really makes wind and drop easy to understand. You really need the full 1000 yds to see it and the full effect.

    Watching this youll be amazed at how high the trace is above the line of sight and the curve of the wind on the bullet. The bullets trace will start out almost straight heading for the target 10-12 over then slowly start to curve back in on the way up then as it slows it starts to drop and the winds effect increases the curve bringing the bullet into the target.

  3. #23
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    Here is an illustrative chart of a bullet fired at a 1000yd target.
    It shows a 10 mile per hour cross wind acting on only the first 100yds of the bullets 1000yd flight. The remaining 900 yds were "free of wind" for the purpose of this informational chart. The bullet moves 19 inches off the target. This shows the effect of the wind importance of the First Wind to act on the bullet.
    If we charted this same 1000yds., this time having no wind for the first 900yds and blowing 10MPH across the range like before in the last 100yds, in other words, this same 100 yards of cross wind only acted on the segment described as 900 - 1000yds, the bullet would have moved only the amount shown in the chart from zero (0) to 100yds., basically very little by contrast. The bullets moves 1 inch off the target.




    Sorry for the very large image. I am still learning how to reduce size in a hosted service.
    Last edited by Chill Wills; 01-16-2025 at 07:30 PM.
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  4. #24
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    Quote Originally Posted by Tatume View Post
    True.



    I'm not so sure. This is the topic of many heated discussions. Here is my opinion.

    First, many people, including some accomplished shooters, believe that the wind changes the direction in which the bullet travels. It doesn't. Side wind displaces the bullet sides ways, but the direction of travel is unchanged. Ask any pilot how the wind affects an airplane in flight. Imagine that you're flying in dead calm air and your direction of flight is directly towards your destination. Along the way you enter an area where there is a 10 mph wind at 90 degrees to your direction of flight, and you fly for one hour without making any correction. At the end of the hour you re-reenter dead calm air. You will miss your destination by 10 miles in the direction in which the wind blew. It doesn't matter if the side wind was near the destination or closer to the departure point.

    Second, a faster bullet will be affected by wind displacement less than a slower bullet. This is simply because the wind has more time to exert force on the slower bullet. By this logic, the wind down range has a greater effect than the wind near the firing line, because the bullet is slower down range.
    You haven’t shot any 1000 yard matches have you? Just for the record I don’t agree with your assessment.

    Kenny Wasserburger.

  5. #25
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    Quote Originally Posted by Chill Wills View Post
    Here is an illustrative chart of a bullet fired at a 1000yd target.
    It shows a 10 mile per hour cross wind acting on only the first 100yds of the bullets 1000yd flight. The remaining 900 yds were "free of wind" for the purpose of this informational chart. The bullet moves 19 inches off the target. This shows the effect of the wind importance of the First Wind to act on the bullet.
    If we charted this same 1000yds., this time having no wind for the first 900yds and blowing 10MPH across the range like before in the last 100yds, in other words, this same 100 yards of cross wind only acted on the segment described as 900 - 1000yds, the bullet would have moved only the amount shown in the chart from zero (0) to 100yds., basically very little by contrast. The bullets moves 1 inch off the target.



    Sorry for the very large image. I am still learning how to reduce size in a hosted service.
    Spot on. But then again, we have both shot 1000 matches for over 30 years.

    Kenny W.

  6. #26
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    Yup. Kenny knows.
    Chill Wills

  7. #27
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    2nd Amendment of the U.S. Constitution. - "A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."

    "Before you argue with someone, ask yourself, is that person even mentally mature enough to grasp the concept of different perspectives? Because if not, there’s absolutely no point."
    – Amber Veal

    "The Highest form of ignorance is when you reject something you don't know anything about".
    - Wayne Dyer

  8. #28
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    Last edited by M-Tecs; 01-15-2025 at 04:07 AM.
    2nd Amendment of the U.S. Constitution. - "A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and bear Arms, shall not be infringed."

    "Before you argue with someone, ask yourself, is that person even mentally mature enough to grasp the concept of different perspectives? Because if not, there’s absolutely no point."
    – Amber Veal

    "The Highest form of ignorance is when you reject something you don't know anything about".
    - Wayne Dyer

  9. #29
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    [QUOTE=Tatume;5820433]True.



    I'm not so sure. This is the topic of many heated discussions. Here is my opinion.

    First, many people, including some accomplished shooters, believe that the wind changes the direction in which the bullet travels. It doesn't. Side wind displaces the bullet sides ways, but the direction of travel is unchanged. Ask any pilot how the wind affects an airplane in flight. Imagine that you're flying in dead calm air and your direction of flight is directly towards your destination. Along the way you enter an area where there is a 10 mph wind at 90 degrees to your direction of flight, and you fly for one hour without making any correction. At the end of the hour you re-reenter dead calm air. You will miss your destination by 10 miles in the direction in which the wind blew. It doesn't matter if the side wind was near the destination or closer to the departure point.

    Second, a faster bullet will be affected by wind displacement less than a slower bullet. This is simply because the wind has more time to exert force on the slower bullet.
    I always believed this (based on shooting smokeless hi powers) so I brought that logic with me into blackpowder - it doesnt take much wind to put a roundball out in the white at 100 yards so i drove them s hard as I could whilever accuracy held up .....only to be told later that was counter productive - something to do with the round ball shape, a slower ball was actually dislodged less over the distance - sounded counter intuitive but the teller quoted some ballistics to back his story - anybody know this is true or just another story?

  10. #30
    Boolit Grand Master Tatume's Avatar
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    Joe – Hey Alex, where did you hold?
    Alex – Nine o’clock in the nine ring.
    later
    Joe – Hey Alex, that put all my shots at three o’clock in the nine ring.
    Alex – That’s where mine went too. ��

  11. #31
    Boolit Master TurnipEaterDown's Avatar
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    Quote Originally Posted by M-Tecs View Post
    A bullet does not have an engine to maintain a constant speed so wind drift is similar to drop. It's a parabolic curve not a straight line. As the bullet slows the wind has longer to affect it's time of flight. The question that is highly debated is at what point are the effects of wind the greatest?
    Interesting conversation/tutorial, and admittedly one which I want to investigate to learn more. Have shot some dozen + head of game, and numerous varmints in Wy, 350-500 yds, w/ success, but certainly could do to learn more. 350 yds after all really isn't so very far.

    I do think a number of people are in a bucket like me though: range w/ access tops out 200 yds, so difficult to practice the skill. 22 RF sounds like the right thing to do, but mine are not capable of enough precision to sort wind from variability in POI I think.
    Am considering cast from a rifle w/ more precision, and while not down to 22 RF Std Vel speed, they are closer than jacketed.

    Anywho:
    The drift / airplane comparison.

    The wind puts a Force on the bullet by acting on the presented Area.
    F = MA (Force, Mass, Acceleration)
    A is Acceleration, Not Velocity.

    If the wind has acted on a bullet for a portion of it's flight, it has created an acceleration, and that function integrated over the time of action results in a velocity. If the wind then suddenly stops, the bullet Still has that Velocity in the direction in which the wind accelerated it, just no more acceleration.
    Due to the Velocity created by the wind force accelerating it, as the time of flight continues, the static velocity (i.e. no additional acceleration - yes, there will be decay...) continues to produce offsetting motion on path to target. O=VT, (O=offset distance, V=Velocity, T=Time).

    The airplane Engine I think has nothing to do with it.
    More likely the airplane rudder, adjusted to keep the heading constant, provides the offsetting Force to produce zero acceleration of the plane perpendicular to the desired path. However, for the path to be offset, then there is likely something more complicated going on there than just average/bulk wind speed. However, I am not a pilot, nor an aerospace engineer.

    The wind from the side will also create Lift, OR Depression of the bullet path depending on which side (L/R) it is presented from, and what way (RH/LH) the twist is.
    A fellow who used to be on here ("OS OK" I remember) was kind enough to remind me of that because it makes a notable difference w/ 22 RF on 100 yd target.
    While I understood airflow, curvature of body, lift & drag, he was kind enough to relate it to the 22 RF. My mind was baseballs. golf balls, airfoils on cars, artillery shells, and airplanes. It should have been rather apparent to me that a baseball or golf ball which is going much slower than a 22 being affected pointed to the RF also being effected, but rather than embarrass me he helped me understand. Very fine fella. Too bad he is gone.

    If I remember right, TC twisted some barrels "backward"/"opposite of norm" for some chamberings. Never knew why. Maybe someone here does.

  12. #32
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    I restored the wind chart that went missing in post 23. If you haven't seen it, take a look.

    Joe and all, In the case of the round ball, if you could drive it fast enough, as in crazy fast and you could have the ball arrive at the target still faster than about 1800 or 1900 fps, you could over come the poor wind drift performance.
    It is hard to conceptualize and even harder for us laymen to write about in an easy to understand way, but, in a nutshell, a bullet who's flight is mostly in the trans-sonic range will be pushed around more than a subsonic bullet, .....or a supersonic bullet that maintains a velocity above the teens all the way to the target.
    There for, the 22rf and all BPCR ballistics are in a fight for there lives so to speak, because of the greater effect the wind has on them. This is true and in addition to anything you want to say about "time of flight' comparisons. With this in mind, you can see how 22's, BPCR bullets, magnum velocity handgun bullets and any other bullet, like cast rifle bullets that operate in (about) the 1100 to 1900 FPS range have more drift than ones moving slower or faster during their flight.


    This subject gets kinda heady and can give brain damage trying to get rapped around it, do to the fact that what may seem reasonable and intuitive is not with every example someone can throw out there.

    Thanks for taking the time to read to this point.
    Last edited by Chill Wills; 01-17-2025 at 06:42 PM.
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  13. #33
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    Bullets do not have a rudder, or a pilot or an engine. Hence it’s not very comparable. The effects are generally the same yet are compensated by the 3 above things mentioned.

    Kenny Wasserburger

  14. #34
    Boolit Master semtav's Avatar
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    Couple things to keep in mind re airplane vs bullet.
    In tatume's example above, the airplane is held on a constant heading throughout the entire flight. The same cannot be said for the bullet.

    Air temp/altitude have the opposite effects on said objects. The thinner the air the easier it is to drive a bullet thru it, the thinner the air the harder it is to propel an airplane thru it.

    And now that got me to thinking. Does a 10 mph crosswind have the same affect on a bullet in 100 deg as it does in 0 deg?

  15. #35
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    Quote Originally Posted by semtav View Post
    And now that got me to thinking. Does a 10 mph crosswind have the same affect on a bullet in 100 deg as it does in 0 deg?
    Without digging through texts that I used for fluid dynamics 35 years ago, I am going to say: No, the same effect should not be produced by crosswind in varying air temperatures. Colder air is denser and the density should have an effect on the impingement forces produced. How much different, don't know.
    Logically the density of the air should affect things. If true, same would go for altitude.
    Haven't used my fluid dynamics in a very long time...

  16. #36
    Boolit Grand Master Don McDowell's Avatar
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    Quote Originally Posted by semtav View Post
    Couple things to keep in mind re airplane vs bullet.
    In tatume's example above, the airplane is held on a constant heading throughout the entire flight. The same cannot be said for the bullet.

    Air temp/altitude have the opposite effects on said objects. The thinner the air the easier it is to drive a bullet thru it, the thinner the air the harder it is to propel an airplane thru it.

    And now that got me to thinking. Does a 10 mph crosswind have the same affect on a bullet in 100 deg as it does in 0 deg?
    The windage adjustments needed in different temperatures is not affected much. Temperature does have an affect on elevation adjustments
    Long range rules, the rest drool.

  17. #37
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    Quote Originally Posted by Chill Wills View Post
    I restored the wind chart that went missing in post 23. If you haven't seen it, take a look.

    Joe and all, In the case of the round ball, if you could drive it fast enough, as in crazy fast and you could have the ball arrive at the target still faster than about 1800 or 1900 fps, you could over come the poor wind drift performance.
    It is hard to conceptualize and even harder for us laymen to write about in a an easy to understand way, but, in a nutshell, a bullet who's flight is mostly in the trans-sonic range will pushed around more then a subsonic bullet, .....or a supersonic bullet that maintains a velocity above the teens all the way to the target.
    There for, the 22rf and all BPCR ballistics are in a fight for there lives so to speak because of the greater effect the wind has on them. This is true and in addition to anything you want to say about "time of flight' comparisons. With this in mind, you can see how 22's, BPCR bullets, magnum velocity handgun bullets and any other bullet like cast rifle bullets that operate in the (about) 1100 to 1900 FPS range have more drift than ones moving slower or faster during their flight.


    This subject gets kinda heady and can give brain damage trying to get rapped around it, do to the fact that what may seem reasonable and intuitive is not with every example someone can throw out there.

    Thanks for taking the time to read to this point.
    Thanks for the further explanation - the round ball thing was a puzzle but I saw it play out on the range, 1800fps is about the practical upper limit and that puts the entire (100yd) journey right in that trans sonic range. Major lesson for me is pay attention!!! . We shoot in what most would consider fairly friendly conditions but even then, 4 to 6 inches drift is common at that range.

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