New memer, question about wind effect on bullets

[injb]

Hi, this is my first post here. I've been looking for a forum where I can learn more about precision shooting, not specifically Olympic stuff but just general principles. I hope this is the right place to post questions like this. I found this video (timestamped link below) from a Biathlon coach, but I don't see why this issue would be specific to that discipline. He says that wind affects the rifle more than it affects the bullet, and that this is why wind closer to the shooter matters more than wind downrange. I have never heard this before. I know that wind close to the shooter matters more but I always thought this was due to the fact that gives the bullet a push earlier in it's travel.

Is he correct about the reason that wind near the shooters position has a bigger impact? I would have thought you'd be able to see any deflection of the rifle in your sight picture and compensate for it if that was the case.

https://www.youtube.com/watch?v=DRUceCXg6pc&t=162s

[Tim S]

Yes, a very string wind can buffet a shooter. I'd imagine this could happen more often in Biathlon than smallbore because: 1) Biathlon ranges are more open to the weather; and 2) Biathletes don't wear the heavy jacket that smallbore shooters do, which may limit how tightly the sling can lock the position in.

As for being able to compensate, remember the wind will blow against the rifle as well as the shooter. And secondly, wind is very rarely totally constant or predictable.

[Rover]

Remember, the wind doesn't just blow....it sucks!

[rgibson]

If you want to make sense out of the debate on whether wind close to the shooter or farther downrange affects the projectile more, consider the following to make your own conclusion.

From listening to the expert ballisticians, the ballistic coefficient (BC) of a projectile gets lower as the velocity decreases. The higher the the BC, the more aerodynamic.

Also, the projectile is much higher off the deck further downrange.

Having spent some time behind a spotting scope watching bullet traces while scoring long range shooting I see what appears to me as much more horizontal dispersion, or curve, to the trajectory in the last half of travel. For a test of your own, put a no wind zero on a rifle and have a competent shooter fire at a target at 1000 yards in a steady, full value 10 mph or higher wind. Watch the trace with a spotting scope.

As far as the wind moving the shooter, I remember standing on the 200 yard line at Perry when a gust of wind would have you looking through your sights at your own target one second and the next second at the next target over; luckily not as the shot broke.

It’s all great fun ain’t it!

[injb]

If you want to make sense out of the debate on whether wind close to the shooter or farther downrange affects the projectile more, consider the following to make your own conclusion.

From listening to the expert ballisticians, the ballistic coefficient (BC) of a projectile gets lower as the velocity decreases. The higher the the BC, the more aerodynamic.

Also, the projectile is much higher off the deck further downrange.

Having spent some time behind a spotting scope watching bullet traces while scoring long range shooting I see what appears to me as much more horizontal dispersion, or curve, to the trajectory in the last half of travel. For a test of your own, put a no wind zero on a rifle and have a competent shooter fire at a target at 1000 yards in a steady, full value 10 mph or higher wind. Watch the trace with a spotting scope.

As far as the wind moving the shooter, I remember standing on the 200 yard line at Perry when a gust of wind would have you looking through your sights at your own target one second and the next second at the next target over; luckily not as the shot broke.

It’s all great fun ain’t it!

Thanks for the reply. Actually I didn't realize there was a debate on this. But I wonder if we're talking about quite the same thing. When I talked about wind closer to the shooter having a different effect, I was assuming the case where the wind is different at the shooter's position vs downrange. I think that video I referenced assumed the same thing - he was saying to pay more attention to the closer wind flags than the further ones. That wouldn't make sense if they were all showing the same thing.

In the extreme case, suppose a puff of wind of a given strength is going to blow the bullet once, briefly, but we can vary where that happens. Then the question is, which is worse for the bullet: a puff of wind at the shooter's position, or the same puff of wind near the target? When the puff happens, it's going to impart a sideways force to the bullet, making the bullet move off course at an angle. In that case, the longer the bullet travels after being pushed by the wind, the more it'll drift off target. It'll be a linear relationship between time and drift.

In your example, the wind is constant for the full journey of the bullet. So, constant force = constant acceleration, and so the bullet's trajectory will be a curve that steepens as the bullet gets further downrange. I think it's exasperated by the fact that the bullet is slowing down, so its sideways motion as a function of distance downrange increases even more. I can see why in this case you could argue that the greater sideways velocity near the end of the travel has a bigger impact, but that's moot because you can't account for it separately if the wind is constant all the way downrange.

[rgibson]

You misunderstood, my friend. I suggested watching the bullet trace in enough wind so that you could see where the most deflection occurred. Wind causes issues at all yard lines. I think that if I watch the flags downrange and you watch the close ones we’ll have it covered, right? Good luck and great shooting!

[injb]

You misunderstood, my friend. I suggested watching the bullet trace in enough wind so that you could see where the most deflection occurred. Wind causes issues at all yard lines. I think that if I watch the flags downrange and you watch the close ones we’ll have it covered, right? Good luck and great shooting!

Sorry I still don't understand then. I thought the question of where the most deflection occurred was in order to figure out which wind flags to pay the most attention to when they are showing something different. But if they're all showing the same thing, then this question doesn't arise.

[rgibson]

It takes a lifetime to try and figure out the fickle wind. You must pick out the flag on the range which is giving you the best indications of what the wind is doing to your bullet given the results on your target. Buy some books on reading the wind. Nancy Tompkins book “Prone and Long Range Rifle Shooting” has an excellent chapter on “Wind.” The answer to your question from one of the greatest long range shooters (Tompkins) is on page 232.

[injb]

Thanks for the recommendation. I might pick that up at some point, but I am not really trying to learn how to read the wind right now though... I have bigger problems for the time being, like being able to shoot consistently when there's no wind! I don't have access to a long distance range and the range I do shoot at doesn't have wind flags anyway.

I am just curious to understand the principles at work here. What the biathlon guy said surprised me - when I shoot in a ~10mph wind with little to no shelter for me and my rifle, I see my bullets landing an inch or so off target, but I don't feel or see the rifle moving. According to this guy, the wind blowing the rifle is responsible for most of the displacement in biathlon shooting. But maybe he's talking about far stronger winds etc. I suppose their rifles are a lot wider too!

Anyway you piqued my curiosity in saying there's a debate about where wind matters more - I thought it was widely accepted that wind closer to the shooter matters more (although for a completely different reason that this biathlon guy said), and I just wanted to understand what the counter argument is.

[Peter_Scant]

Here's some wind videos for smallbore from Heinz Reinkemeier
https://www.youtube.com/watch?v=2_xCBD9hQSo
https://www.youtube.com/watch?v=GEk1J8h1AX4

For fullbore I'd recommend the wind book for rifle shooters by Miller and Cunningham.

By the way, with regards to wind effects, not everything transfers between smallbore @50m and fullbore @1000yd/900m

[william]

Thanks for the recommendation. I might pick that up at some point, but I am not really trying to learn how to read the wind right now though... I have bigger problems for the time being, like being able to shoot consistently when there's no wind! I don't have access to a long distance range and the range I do shoot at doesn't have wind flags anyway.

I am just curious to understand the principles at work here. What the biathlon guy said surprised me - when I shoot in a ~10mph wind with little to no shelter for me and my rifle, I see my bullets landing an inch or so off target, but I don't feel or see the rifle moving. According to this guy, the wind blowing the rifle is responsible for most of the displacement in biathlon shooting. But maybe he's talking about far stronger winds etc. I suppose their rifles are a lot wider too!

Anyway you piqued my curiosity in saying there's a debate about where wind matters more - I thought it was widely accepted that wind closer to the shooter matters more (although for a completely different reason that this biathlon guy said), and I just wanted to understand what the counter argument is.

You, sir, are overthinking.

[injb]

Here's some wind videos for smallbore from Heinz Reinkemeier
https://www.youtube.com/watch?v=2_xCBD9hQSo
https://www.youtube.com/watch?v=GEk1J8h1AX4

For fullbore I'd recommend the wind book for rifle shooters by Miller and Cunningham.

By the way, with regards to wind effects, not everything transfers between smallbore @50m and fullbore @1000yd/900m

Thanks, those are fascinating, especially the curved patterns that show how the bullets get deflected in stronger winds.