does wind affect elevation

[johnrice]

shot a local match in 30 mph full value wind was hitting low, two seperate indivuals told me when the wind is blowing like this i need to add 2 to 3 tenths in elevation.
i ran the numbers in ab no matter how high the wind was there was no elevation change, could this be just a phenomenon of this paticular range? i/e wind comming down off thop of a mountain?

 

[Matches Malone]

AJ comes to mind. If you have AJ enabled then it’s auto calculating it in. So in short, it’s possible in 30 mph wind depending on distance.

 

[johnrice]

AJ comes to mind. If you have AJ enabled then it’s auto calculating it in. So in short, it’s possible in 30 mph wind depending on distance.

going to check ab, i believe i have everything turned off aj and spin drift

 

[Steel head]

Right hand twist
Left to right can hit low
Right to left can hit high

Mountain winds can do some funky things.
Upswells and downswells are common.

 

[johnrice]

Right hand twist
Left to right can hit low
Right to left can hit high

Mountain winds can do some funky things.
Upswells and downswells are common.

It was a left to right wind. Shooting directly into the base of a lone desert mountain.

 

[morganlamprecht]

ive only done it with 308 once purposely, but ive shot a ton of 6 and 6.5...idk how AB calculates it, but it doesnt match anywhere ive ever shot with 6 or 6.5...or for any of the other top shooters in our region...in south tx the ground is 99% flat, so its just wind, no hills to worry with

if you put wind speed 1 into a kestrel it moves your dope up/down something like .1mil per 8-10mph...depending on rounding, it can cause the calculator to give a .2-.3 elevation change in 15-20mph winds...the wind almost always blows 10-20mph here

the last time i went out with 308, i hit a 10" 1k plate, holding edge, wind was like 2-3 mph from 1-2oc...the very next day a front blew in and the winds were 12-22mph...went back out and hit the same plate w/ 3.7-4.5 mils of wind, using the exact same elevation...if i input that wind into my kestrel for ws1, it changed my dope .2-.3 iirc, which would have put me consistently over a 10" plate (it was a right to left wind)

that same day my buddy was shooting his 6brx at the TYL rack @ 400, he had just recently got a kestrel...had been using geoballistic for a year or 2 before (doesnt havent AJ)...he said his dope was always 1.7 before, but the kestrel, with ws1 and direction of fire captured was telling him 1.5x...pretty sure it rounded down...and he hit the first 3 plates in the stem @ 6oc...i had him zero out ws1 in his kestrel, and it told him 1.7...he cleaned the rack with 1.7, center hits

ive purposely taken a rifle out and input every value in a kestrel and trued it up to 1k using wind/dof/lat/any amount of small zero offset i could measure...i noted the standard elevation (pre wind)...then waited for another windy day and shot at a different location, in different winds...with everything captured, my dope was off the amount it changed post wind inputs...remove wind, and back to center hits on target

i know of multiple other shooters from my local club who got burned by ws1/AJ shooting in their first high wind matches...probably 5 stories similar to above

since i got my first kestrel in '15 or '16, when i figured out from shooting and talking to other shooters more experienced than me at the time... zeroing ws1 removed the small day to day elevation issues in was having, i havent used it since...ive shot multiple matches in NM, OK, FL, CO, and TX...some of those matches had 30mph winds...never used it once for targets out to 1520 yds...i dont miss high/low very often, its 99% wind/shooter wiggle...the only times i can remember myself and squads mates missing consistently high/low was due to out of the ordinary lighting/cloud/mirage conditions...those differences were usually in the .2-.4 range, wind wasnt a consistent factor in any of them

the place i normally shoot/verify dope is next to a thick tree/brush line, so the 100 yds line is pretty much protected, the prevailing wind is from 2-3oc and it can be blowing 15mph and ground level from shooter position to 100 yds, you almost cant feel anything ...shooting to the 800 yd target you leave that brush line and clear the trees/brush...there are 6" orange dots painted on a 4'x8' sheet of metal, and ive hit those same dots with the same dope (on same DA days), holding straight up and holding 2-2.5 mils of wind from all of my rifles (and so have my buddies who shoot there along with the land owner)


all that said...to say...lol we have purposely tried to set up and see it in order to make it match the kestrel...it would make using the kestrel easier for us...but however the kestrel calculates it...it doesnt match when the winds change, for any of us...

 

[RTH1800]

David Tubb could answer this well. Short answer is yes. Every wind has a vertical component. Often gets lost in the noise.

 

[Jack Master]

The high and Low effect of this chart is caused by aerodynamic jump (AJ).

AJ for a 90 or 270 degree wind is 0.1 Mil per 10mph (0.3 moa per 10mph) This is the easy way I remember this if you are having to manually add it to your data.

 

[Greg Langelius *]

Drop is a direct factor of Time of Flight; headwind increases it, tailwind decreases it.

Crosswinds can also induce Magnus Effect.

As you view a spinning bullet from the upwind side, the upper or lower surface that is spinning away from you generates less aerodynamic drag, has less pressure, and thus generates aerodynamic lift in that direction, exactly like a wing.

As the other upper or lower side spins into the wind, the air on that side backs up in comparison, due to relative stagnation, and has the higher pressure.

This pressure differential generates lift in the direction of lower pressure, pushing the bullet toward the lower pressure. This is exactly the same principle as the way aircraft fly.

POI prediction is an art, not a science. Air currents in the intervening space from rifle to target can vary in all three axes, and over time, to effectively make each trajectory unique.

Greg

 

[_Raining]

600 yards no wind for my rifle in AB mobile app shows U 11.875 MOA, L .250 MOA
Add 30 MPH wind left to right: U 13.0, L 10.875

Which is about .33 MIL's difference in elevation.

 

[Jack Master]

600 yards no wind for my rifle in AB mobile app shows U 11.875 MOA, L .250 MOA
Add 30 MPH wind left to right: U 13.0, L 10.875

Which is about .33 MIL's difference in elevation.

Just curious here - Could you try that for 1000 yards and see what your vertical difference is? is it the same .mils? or real close?
Thanks

 

[Gunfighter14e2]

Drop is a direct factor of Time of Flight; headwind increases it, tailwind decreases it.

Crosswinds can also induce Magnus Effect.

I have seen a head wind raise the impact, and a tail wind lower it. To me it's were the river of wind intersects the bullet in flight. Most cross winds follow the chart above, is what I've seen.

 

[Greg Langelius *]

I have as well. But it's my conclusion that surface air/terrain turbulence generates a lot of its own vertical components.

 

[Dthomas3523]

Just talking AJ here, not up and down winds caused by terrain......

My understanding is AJ affects the bullet within a very short distance. Short enough that it can happen within your 100yd zero range.

So, theoretically, wouldn’t the jump be factored into your zero already? For better or worse.

Don’t most calculators assuming zero AJ factored into the zero and then add it in when you input wind1 or turn AJ on (software dependent)?

If the above assumptions are correct, I think this is why calculators don’t do so well with AJ.

As such, I keep my wind1 at zero and cant remember the last time I missed vertically (that I couldn’t attribute to shooter error or wobble).

 

[johnrice]

The high and Low effect of this chart is caused by aerodynamic jump (AJ).

AJ for a 90 or 270 degree wind is 0.1 Mil per 10mph (0.3 moa per 10mph) This is the easy way I remember this if you are having to manually add it to your data.

View attachment 7370479

Okay here's what happened. I thought I was getting ready for these team matches and produced a hard range card, had zero wind inputed. Was going to use my rifle mph for when calls. Had no idea how it affected the elevation impacts. So I'm learning a lot from you guys.

 

[Dthomas3523]

@lowlight

Topic for the next podcast with Litz and Emil:

Aerodynamic jump: what it is, how it works, and why some people don’t see it as much or use it in their software

 

[Dthomas3523]

Okay here's what happened. I thought I was getting ready for these team matches and produced a hard range card, had zero wind inputed. Was going to use my rifle mph for when calls. Had no idea how it affected the elevation impacts. So I'm learning a lot from you guys.

Keep in mind, that graphic is exaggerated to show the effect properly.

For example, a head wind or tail wind does affect the velocity, but inside 1k it’s almost so minuscule that you won’t see it on paper.

 

[_Raining]

Just curious here - Could you try that for 1000 yards and see what your vertical difference is? is it the same .mils? or real close?
Thanks

1000 yards no wind: U 27.375, L .625
1000 yards 30 mph wind from 9 o clock: U 28.5, L 21.0

1.125 MOA or .33 MILs

Honestly surprised that it is the same difference.

Note: It is the same 1.125 MOA diff at 100 yards as well.

 

[morganlamprecht]

Just talking AJ here, not up and down winds caused by terrain......

My understanding is AJ affects the bullet within a very short distance. Short enough that it can happen within your 100yd zero range.

So, theoretically, wouldn’t the jump be factored into your zero already? For better or worse.

Don’t most calculators assuming zero AJ factored into the zero and then add it in when you input wind1 or turn AJ on (software dependent)?

If the above assumptions are correct, I think this is why calculators don’t do so well with AJ.

As such, I keep my wind1 at zero and cant remember the last time I missed vertically (that I couldn’t attribute to shooter error or wobble).

this is why when we tried to force scenarios to see it, we used dof and wind in the 100 yd zero

Example: if the predominant wind was 3-4 mph crosswind, and that input into the kestrel made the zero .07mil high @ 100, we measured offset best we could from the zero being .25” off...using generic numbers as example

also have done it just getting a perfect zero and ignoring 100 yd input from wind...neither worked out consistently when the winds changed

if I put a 20mph wind from 3oc one of my match rifles dope is 2.08...if I change the wind to 9oc, it’s 2.47....I’ve never been different .4mil @ 500 in any wind ever and I’ve shot in 15-30 mph winds both directions at the heatstroke In OK twice...the way the range is set, u shoot both directions from a single ridgeline

 

[Dthomas3523]

this is why when we tried to force scenarios to see it, we used dof and wind in the 100 yd zero

Example: if the predominant wind was 3-4 mph crosswind, and that input into the kestrel made the zero .07mil high @ 100, we measured offset best we could from the zero being .25” off...using generic numbers as example

also have done it just getting a perfect zero and ignoring 100 yd input from wind...neither worked out consistently when the winds changed

if I put a 20mph wind from 3oc one of my match rifles dope is 2.08...if I change the wind to 9oc, it’s 2.47....I’ve never been different .4mil @ 500 in any wind ever and I’ve shot in 15-30 mph winds both directions at the heatstroke In OK twice...the way the range is set, u shoot both directions from a single ridgeline

So, let’s say I have a 100yd zero input into my kestrel (looking at it now and doing the inputs).

I input a 10mph 3 o’clock wind. And input a target distance of 100yds. It’s telling me I should have an AJ of .1 (for sake of example, lets say this was the wind conditions when I zero

You may have stated this above and I didn’t interpret it correctly.

If I set my turrets to 0 elevation that day, theoretically wouldn’t I have 10mph of AJ in my zero?

To make the calculator work, wouldn’t I need to set my turrets to .1 up?

 

[Dthomas3523]

Or did you already try that and see how it worked on other days?

 

[morganlamprecht]

So, let’s say I have a 100yd zero input into my kestrel (looking at it now and doing the inputs).

I input a 10mph 3 o’clock wind. And input a target distance of 100yds. It’s telling me I should have an AJ of .1 (for sake of example, lets say this was the wind conditions when I zero

You may have stated this above and I didn’t interpret it correctly.

If I set my turrets to 0 elevation that day, theoretically wouldn’t I have 10mph of AJ in my zero?

To make the calculator work, wouldn’t I need to set my turrets to .1 up?

Yes, we’ve tried it both ways...zeroing to match the kestrel with ws1 input to match the conditions...and zeroing ignoring it

it hasn’t matched 100% either way...the day I matched 100 yd wind, I had to tweak a previous tried and true velocity and BC to make mid range and 800 yds match the in the kestrel...then when I shot in a different wind condition (direction and value) my dope was off the amount I tweaked the BC and velocity...set everything back to standard, and dope was perfect to 1k

 

[Matches Malone]

Yes, we’ve tried it both ways...zeroing to match the kestrel with ws1 input to match the conditions...and zeroing ignoring it

it hasn’t matched 100% either way...the day I matched 100 yd wind, I had to tweak a previous tried and true velocity and BC to make mid range and 800 yds match the in the kestrel...then when I shot in a different wind condition (direction and value) my dope was off the amount I tweaked the BC and velocity...set everything back to standard, and dope was perfect to 1k

So if I’m understanding, shooting with a zero wind zero AJ comes into play, but zeroing in the condition washes out the need for AJ correction?

 

[Dthomas3523]

So if I’m understanding, shooting with a zero wind zero AJ comes into play, but zeroing in the condition washes out the need for AJ correction?

Theoretically. If you zero’d in wind and turned your turrets to zero, you have AJ factored in your zero.

But, many have attempted to either A) zero in no wind or B) set their zero to account for the AJ that should be present

But it’s still not working out better (in fact it works much worse at times) that just zero’ing without any adjustment and then turning wind1 or AJ off.

My thoughts is that’s because having a bit of AJ factored into your zero ends up being somewhere in the middle and the rest of the AJ you see in action is less than shooter/rifle/wobble/wind capability.

 

[morganlamprecht]

So if I’m understanding, shooting with a zero wind zero AJ comes into play, but zeroing in the condition washes out the need for AJ correction?

according to what I’ve read from AB and seen in my kestrel....that’s what their math says

0 wind in kestrel For my 6cm...
50 yd = .23u
100 = 0.00
500 = 2.27u
1k = 7.03u

20mph from 9oc...
50 = .43u
100 = .2u
500 = 2.47u
1k = 7.22u

20mph from 3oc...
50 = .03u
100 = .2d
500 = 2.08u
1k = 6.82u

it’s locking in .2mil basically from muzzle to target depending on wind direction

so according to the kestrel, that crosswind shifts your zero as much as .4 if u go from 3oc to 9oc winds...I’ve never seen or seen anyone I trust be able to match that anywhere I’ve shot

From my perspective, I don’t care what the math does/says...I’m there to hit a lot of targets on the first shot...if I put in all the inputs and it causes shifts that miss, and I remove them and the shifts go away...to hell with what the paper math says

 

[Steel head]

I have seen a head wind raise the impact, and a tail wind lower it.

One of my favorite shooting Spots has that happen quite often.
A solid headwind often requires .6-.8 less elevation at 1810 yards.
Steep river valley.

 

[johnrice]

so just when i thuoght i was getting a grasp on my garmin. so is it possible to true your data rock solid and go to a different area say from sea level to 4500 ft and be off again?

 

[Dthomas3523]

so just when i thuoght i was getting a grasp on my garmin. so is it possible to true your data rock solid and go to a different area say from sea level to 4500 ft and be off again?

If you trued it properly, you should be good.

But there are other factors. For example, if you’re loading your own ammo and you’re not in a good powder node, the environmental change may throw your ammo out of wack.

 

[johnrice]

i was setting the garmin to a 3 or 9 oc wind, i did not care and setting wind speed 1 to zero and wind speed 2 to 10 mph and adjusting my wind call off of that.
wich worked ok untill i shot in these winds. i pretty much set my self up for failure ?

 

[Dthomas3523]

i was setting the garmin to a 3 or 9 oc wind, i did not care and setting wind speed 1 to zero and wind speed 2 to 10 mph and adjusting my wind call off of that.
wich worked ok untill i shot in these winds. i pretty much set my self up for failure ?

I think the Garmin allows AJ to be turned on and off. If I remember correctly, wind1 doesn’t affect AJ on the Garmin. But I haven’t used Garmin in a while. I could be wrong.

 

[Steel head]

i was setting the garmin to a 3 or 9 oc wind, i did not care and setting wind speed 1 to zero and wind speed 2 to 10 mph and adjusting my wind call off of that.
wich worked ok untill i shot in these winds. i pretty much set my self up for failure ?

I usually Measure the high and low in strong winds and adjust accordingly.
Is garmin AB based?

 

[johnrice]

I usually Measure the high and low in strong winds and adjust accordingly.

Are you setting the low as wind one and high as wind 2?

 

[Steel head]

Are you setting the low as wind one and high as wind 2?

Yes but only in high winds, at low to moderate winds I set wind 1 to zero and just use a simple G1 wind hold talked about here and favor slightly high or low depending on direction like the chart jack posted.

Take notes on every wind situation, when I started doing that my ballistics got a lot better.

 

[johnrice]

Thank you

 

[morganlamprecht]

so just when i thuoght i was getting a grasp on my garmin. so is it possible to true your data rock solid and go to a different area say from sea level to 4500 ft and be off again?

I’ve gone from sea level in south tx, to CO @ 4-5000 ft, NM @ 6-7000 ft, OK @ 1-2000 and been spot on to 12-1500 yds...but I wasn’t using any AJ, during truing or those matches...adding the ws1, I would have been off on multiple occasions

not to say that will hold true 100% Of the time, but in my experience, it’s worked really well

 

[richthe1]

Could someone help explain (dumb it down for me) the Kestrel stuff? I just got a kestrel 5700 elite, still learning how to use it. Right now I capture target direction, capture wind speeds WS1 and WS2, and then take my shot. Should I not be using WS1? If so, how do you turn it off?

 

[Rocketmandb]

Drop is a direct factor of Time of Flight; headwind increases it, tailwind decreases it.

Side winds also impact time of flight - as any pilot will tell you. Your bullet travels farther.

 

[Dthomas3523]

Could someone help explain (dumb it down for me) the Kestrel stuff? I just got a kestrel 5700 elite, still learning how to use it. Right now I capture target direction, capture wind speeds WS1 and WS2, and then take my shot. Should I not be using WS1? If so, how do you turn it off?

You just set it to zero wind.

 

[Steel head]

You just set it to zero wind.

This
Wind 1 to zero
Most of the time I don’t even use the wind function of the kestrel, just strong winds

 

[Deleted member 10043]

I live on the high Plains of SE New Mexico and it is almost always windy. But a full value 30 mph wind is going to be variable veritical and horizontal. Almost a waste of ammo. Every shot practically stands alone at long range.

 

[morganlamprecht]

Could someone help explain (dumb it down for me) the Kestrel stuff? I just got a kestrel 5700 elite, still learning how to use it. Right now I capture target direction, capture wind speeds WS1 and WS2, and then take my shot. Should I not be using WS1? If so, how do you turn it off?

there may be a faster way...but how ive done it for years, this is just for the kestrel...can get to similar values using the gun mph method and known full value x wind, etc...all just a means to a similar end

make sure ws1 is set to 0

cycle thru and note every distance i have to shoot, whether its 1, 2, or 5 for a stage...all of them

then capture wind speed

manually set predominant direction...i dont care about using the compass (ive used the compass and target direction/wind capture before, but i found on some large metal tower structures ive shot from, it throws the compass off if youre too close to the metal, so i just quit doing it that way years ago out of habit)

cycle back thru each distance, noting low and high wind

from there i make judgement calls based on terrain/mirage and which wind value i feel its consistently staying closer to...is it always gusting with short let off, or calmer with short gusts...is it staying consistent in the middle...etc

if the winds are light, less than 10mph, or closer targets with smaller overall wind holds...ill usually just set the ws2 value and only cycle thru once...if the wind is max 6 mph and ws2 tells me a .3 max, im not worried much with ws1 being 3-4 mph, i know i just need to come off .3 which likely puts me holding on target anyways

having to cycle thru 2x is why we always tried to get the dope to match with ws1 and AJ in there, it would save some time...but we havent ever been able to

on other apps such as geo and ballistic ae that dont factor AJ, u can just do elevation and wind at the same time...faster, but i dont like using my phone

 

[Greg Langelius *]

Figuring a linear deviation for wind is probably not the best strategy; since under constant wind, deflection grows exponentially with distance, and under inconstant wind, it becomes pretty totally unpredictable.

I've seen (and used a few times) wind flags at a sequence of intervening distances. They can help, but they can't tell us all. Just considering the downrange viewpoint, head and tailwinds are masked by perspective. On many occasions, I have shot on such ranges (Cherry Ridge, Bodines, Odessa, and there must be many others...) where scores often depended largely on shooting mound assignments.

The river of wind is often not a ribbon at all, but rather a tangle of crosscurrents trending in all three axes.

I have shot, and achieved consecutive hits at 1000yd, in a steady 30mph wind. But that's rather a special case, and nowhere near the norm.

It was during my first ever comp at 1000yd. I asked myself whether that was all there was to it.

Time has corrected my Newbie ignorance.

Greg

 

[Jack Master]

Figuring a linear deviation for wind is probably not the best strategy; since under constant wind, deflection grows exponentially with distance, and under inconstant wind, it becomes pretty totally unpredictable.

Aerodynamic jump is linear. The jump happens in the first 30 to 50 yards and sends the bullet in a consistent trajectory after its fully stabilized.
Aerodynamic Jump in a 30mph cross wind = 0.3 mil up or down at 200yds and 1000yds.
Per the Applied ballistics (AB) books - Aerodynamic jump is not caused by magnus effect. Its caused by the wobble of the spinning bullet as it exist the barrel and stabilizes in windy conditions.
I understand the Magnus effect and also used to think it was a factor but I drank the AB coolaid where they proved that is not the case.

 

[Dthomas3523]

Aerodynamic jump is linear. The jump happens in the first 30 to 50 yards and sends the bullet in a consistent trajectory after its fully stabilized.
Aerodynamic Jump in a 30mph cross wind = 0.3 mil up or down at 200yds and 1000yds.
Per the Applied ballistics (AB) books - Aerodynamic jump is not caused by magnus effect. Its caused by the wobble of the spinning bullet as it exist the barrel and stabilizes in windy conditions.
I understand the Magnus effect and also used to think it was a factor but I drank the AB coolaid where they proved that is not the case.

Which means if you zero in wind, and don’t add in the AJ......its never going to work......correct?

 

[Jack Master]

Which means if you zero in wind, and don’t add in the AJ......its never going to work......correct?

my 2c on this.

First of all, if you are zeroing your rifle in more than 10mph wind you're going to have a lot of trouble. Not with only AJ but right and left wind too. I think we all know its not a good situation. But, If you had to zero in high winds you will certainly want to take AJ into account. The easiest way to do this is to look at your ballistic calculator. Put in the wind speed and direction then read the 100yd numbers (use wind 1 on an AB platform). If it tells you to dial 0.1mil up at 100yds I would zero the rifle on the target center (POA=POI) and then slip my turrets to 0.1 up rather then slipping them to 0.0. This will account for the AJ adjustment.

We also want to think about how perfect your rifle zero is to start with? how much "noise" are we dealing with? Are you between clicks to get it just right? Could your fundamentals have changed from today to tomorrow to change your 100 yd zero? If we are zeroing our rifle in less then 10mph wind AJ is lost in the noise because its less then a 0.1mil. If its a 20 or 30 mph day AJ is going to start to matter... but your wind is going to be worse. So again, when zeroing in those wind conditions the AJ is lost in the noise because your wind zero will probably be so far off. Even if you adjusted for the wind, are you sure its right?

Ignoring the fact that zeroing in 20+mph winds gives you a hasty wind zero, at best, lets look at how much the AJ really matters. Again assume a right to left 20mph wind so your zero is 0.2 mil high. If the wind keep blowing that day and you are not using AJ in your calculator you should hit all day. if you are using AJ in the calculator you are .2 mils high for that day because you are adding AJ onto AJ. IF the the wind is gone the next day your are .2mils high all day. If the wind switches left to right you are at a perfect zero if you are not using AJ in your calculator or .2 mil low is your are using AJ in the calculator. either way your are .2 mils high or .2 mils low.

How much does that matter? 0.2 mils at 500yds is 3.6 inches. and 7.2 at 1000. How big is your target?

We can't say "its never going to work" because it could work out. It all depends on what wind you zeroed in, what the wind is today and if your using AJ in your calculator. Is zeroing in wind a good situation? no. Can we account for it? Yes. Can you zero on a better day? I hope so, for the sake of your windage zero which will likely mask the effects of AJ anyways.