Could someone enlighten me on the effect of the wind on pellet trajectory? I know the effect the wind has on bullets but I remember reading somewhere that for pellets things are somehow different?
Air effect
- Thread starter Elgreco
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I’m no expert on ballistics, but my understanding is that there are a couple prevailing thoughts. Both bullets and pellets get affected just the same, but the effect is more pronounced because of the weight of the ammo, it’s shape, and its speed.
Thought 1 Heavy pellet does better in wind because it bucks it better. Thought 2 Faster speed is more important because the ammo has less time to be affected by the wind. I guess there’s a combination of these that probably help. But in either case, a hard wind will blow your pellet away from the POA really good.
Hopefully some of the experts in ballistics can give you a more complete answer, but that’s what I have for now.
Thought 1 Heavy pellet does better in wind because it bucks it better. Thought 2 Faster speed is more important because the ammo has less time to be affected by the wind. I guess there’s a combination of these that probably help. But in either case, a hard wind will blow your pellet away from the POA really good.
Hopefully some of the experts in ballistics can give you a more complete answer, but that’s what I have for now.
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Also, try looking up on YouTube. I don’t have the links, but am sure either or both Matt Dubber and Ted Bier have videos addressing this subject. I’m sure there may be others as well.
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Something like 1" push per mile an hour of wind at 100 yards. Or there abouts from what I have read and seen in my own shooting. That's with wind at 90 degrees to the shot.
So it is significant. A decent slug will be affected about half that amount. The link has a bunch of information on wind deflection.
https://hardairmagazine.com/ham-columns/vertical-deflection-for-pellets-in-crosswind/
Right and left wind pushes pellet up or down
https://www.airgun101.com/index.php/component/allvideoshare/video/aerodynamic-jump-simplified?Itemid=456
So it is significant. A decent slug will be affected about half that amount. The link has a bunch of information on wind deflection.
https://hardairmagazine.com/ham-columns/vertical-deflection-for-pellets-in-crosswind/
Right and left wind pushes pellet up or down
https://www.airgun101.com/index.php/component/allvideoshare/video/aerodynamic-jump-simplified?Itemid=456
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I was just doing some shooting Tuesday morning at long range. Steel gongs at 200 yards with my Impact. I purposefully got up early to beat the wind so that I could shoot that far. I hung ribbons to use as wind flags. Even in a mild wind that barely moved the ribbons the slugs were moving up to a full mil. That’s over 7”. I really learned a lot about wind drift by shooting at that range. It was a real education. I was shooting the NSA .218 24.8 grain slugs. The tiniest change in wind speed and direction would have me chasing my POI all over.
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Yes, wind is surprising on air rifles. There is no difference in the physics between wind drift for a bullet, a ball, a pellet or an arrow. The same math applies in all cases. What changes things the most is time of flight. The longer the thing is in the air, the longer the moving air has to get the projectile moving at the same speed it is moving.
Shambozzie gives a good example above. I was looking at drift on my .177 JSB Exacts @840 FPS the other day. It was funny. I kept running the numbers, not believing the result, and running them again. Then I would check all the inputs and do it again. I just couldn't believe the drift for that setup was almost 4 inches in a 10 mph full value wind. My mind was stuck in powder burner mode and I had to remind myself that flight time is the biggest part of the calculation.
Shambozzie gives a good example above. I was looking at drift on my .177 JSB Exacts @840 FPS the other day. It was funny. I kept running the numbers, not believing the result, and running them again. Then I would check all the inputs and do it again. I just couldn't believe the drift for that setup was almost 4 inches in a 10 mph full value wind. My mind was stuck in powder burner mode and I had to remind myself that flight time is the biggest part of the calculation.
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TOF has some to do with it, and as that may be all your able to currently comprehend, there is more...physics has its way with more than just time.
If you want a headache, then give this guys writings a good read...
https://www.gatewaytoairguns.org/GTA/index.php?topic=169459.0
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This is a link to the first article in the HAM series on external ballistics, including wind drift. One of the main points made is that ballistic coefficient is the major factor affecting wind drift in pellets, not velocity, and not weight itself. You can prove this to yourself using any ballistic software capable of predicting wind drift. The only reason pellet weight seems to make a difference is because for a given caliber heavier pellets usually do have a hgher BC. But enter a pair of values for BC and velocity into your ballistics program and you will see that no matter what pellet weight you enter the wind drift remains the same.
https://hardairmagazine.com/ham-columns/the-external-ballistics-of-diabolo-pellets/
https://hardairmagazine.com/ham-columns/the-external-ballistics-of-diabolo-pellets/
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Some of the explanations given here would have you believe that "faster is better". That is not necessarily the case. The physics of it just doesn't prove that to be true. The BC of the pellet is more important than the speed of the pellet. And the wind at the muzzle is more important than the wind down range.
To the OP, look for something like this. It is called a wind rose. It helps you to see that given the direction of the wind, the pellet will be effected in different ways. For example, a headwind will cause the pellet to impact slightly down from the POA. And Tailwind will cause the pellet to impact high of the POA.
Be sure when you find a wind rose online somewhere, that you are getting the one for PELLETS. Slugs behave abnormally comparatively.
Crusher
To the OP, look for something like this. It is called a wind rose. It helps you to see that given the direction of the wind, the pellet will be effected in different ways. For example, a headwind will cause the pellet to impact slightly down from the POA. And Tailwind will cause the pellet to impact high of the POA.
Be sure when you find a wind rose online somewhere, that you are getting the one for PELLETS. Slugs behave abnormally comparatively.
Crusher
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Every time I start to read about wind and shooting my head starts to hurt but Crusher is correct about speed not necessarily being a plus. There is a theory that discusses that actually called the "delay theory" but rather than talk theory just look at reality. I do some smalbore competition and I have NEVER seen any one using high speed ammo. They always use standard velocity target ammo which is a couple hundred FPS slower than highspeed stuff. Why? Because the standard velocity ammo is more accurate! All I am saying is that there are a lot of factors besides wind that also have to be taken into consideration.
Rick B.
Rick B.
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Some of the explanations given here would have you believe that "faster is better". That is not necessarily the case. The physics of it just doesn't prove that to be true. The BC of the pellet is more important than the speed of the pellet. And the wind at the muzzle is more important than the wind down range.
To the OP, look for something like this. It is called a wind rose. It helps you to see that given the direction of the wind, the pellet will be effected in different ways. For example, a headwind will cause the pellet to impact slightly down from the POA. And Tailwind will cause the pellet to impact high of the POA.
Be sure when you find a wind rose online somewhere, that you are getting the one for PELLETS. Slugs behave abnormally comparatively.
Crusher
Now those I want to get THANK YOU FOR A GREAT PIC AND ADVICE
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