Calculating Headwind With Applied Ballistics App

[mckchome]

Is it possible to calculate the effects of a strong headwind on a bullet’s trajectory? I attempted to do this by changing the wind angle to 12 o clock and moving the wind speed up and down but I didn’t see any changes to the vertical correction (“path” in the language of AB).

Situation: I was shooting my 6mmCM (3100 FPS) with a known, consistent load and I was definitely losing inches as early as 375 yards.

Am I overlooking something? Thanks in advance.

 

[antithesis]

Listen to The Everyday Sniper episode 192. You may find you are wasting your time trying.

 

[mckchome]

Listen to The Everyday Sniper episode 192. You may find you are wasting your time trying.

I will do that, thanks

 

[Reload10]

Unless you're shooting a very slow round (IE 22lr) at elr distances headwinds don't make much of a difference.

If interested, look at what a 22lr round drops at 500 yards with no wind, then enter a 15mph headwind and it will put you well off target.

 

[Olen_4504]

we kind of have this discussion going on in another thread. what can cause elevation issues at distance.

we've covered:

different shooting positions (prone vs bench vs positional), light (sun in front of you, directly behind you), angled shots, thermals/updrafts, mv changes, bc (shouldn't be affecting you at 375yd though), AFF (hornady 4DOF)

http://www.snipershide.com/shooting/threads/105-hybrids-impacting-high.6958620/

 

[mckchome]

we kind of have this discussion going on in another thread. what can cause elevation issues at distance.

we've covered:

different shooting positions (prone vs bench vs positional), light (sun in front of you, directly behind you), angled shots, thermals/updrafts, mv changes, bc (shouldn't be affecting you at 375yd though), AFF (hornady 4DOF)

http://www.snipershide.com/shooting/threads/105-hybrids-impacting-high.6958620/

Thanks I’ll tune into that other thread.

 

[Longshot231]

I went to the long range seminar put on by ABS a while back.

According to Bryan Litz, a headwind or tailwind has negligible effect on a bullet leaving the barrel at several thousand feet per second.

 

[Olen_4504]

Thanks I’ll tune into that other thread.

it probably won't have an exact answer for your situation - but it at least mentions/discusses some possible causes of elevation issues for you to consider and check next time you shoot.

 

[Steel head]

At my primary mile spot I often get headwinds and tailwinds.

A 5mph wind is generally worth 5 tenths +/- depending on direction with my 260.

 

[308pirate]

Is it possible to calculate the effects of a strong headwind on a bullet’s trajectory? I attempted to do this by changing the wind angle to 12 o clock and moving the wind speed up and down but I didn’t see any changes to the vertical correction (“path” in the language of AB).

Situation: I was shooting my 6mmCM (3100 FPS) with a known, consistent load and I was definitely losing inches as early as 375 yards.

Am I overlooking something? Thanks in advance.

You're overlooking the fact that it makes no measurable difference.

 

[antithesis]

Seems early in the flight to see that kind of result. Sounds like you may have had wind swirling down rather than just a headwind.

What amount of wind are we talking about here?

 

[Dthomas3523]

Seems early in the flight to see that kind of result. Sounds like you may have had wind swirling down rather than just a headwind.

What amount of wind are we talking about here?

Let’s start with the amount of head wind it would take to notice a difference at 375yds. Likely tropical storm territory.

OP was obviously seeing results from something other than head wind.

 

[mckchome]

Listen to The Everyday Sniper episode 192. You may find you are wasting your time trying.

Just listened to this. That’s some pretty impressive data. Thanks for the reference.

 

[LawnMM]

At my primary mile spot I often get headwinds and tailwinds.

A 5mph wind is generally worth 5 tenths +/- depending on direction with my 260.

Half a mil? At what distance?

 

[Lowlight]

We had 25MPH to 40MPH winds during our last class here in CO, the winds started at lunch when most of the students left to grab food. So we grabbed Mike's Rifle which was set up and ready to roll... then he and I went to check out the dope in this heavy wind condition since it was pretty much straight at us.

AX 308
6CM Factory Hornady 108s

We shot 600 and 800 yards, we used the truing bar targets we have which are .2 mils at distance, (800 yards = 5.75" )

There was absolutely zero change in dope at both distances. 30MPH+ wind, the hold was less than .5 Mils so it was pretty much straight on, and nothing changed elevation wise.

Not even worth talking about, just dope the wind L-R component and don't sweat the rest.

To give you an example of these winds, one student (MHSA Employee Doug) had his rifle on the bipod on the bench next to us. The wind threw the rifle off the bench on to the ground. So it was strong enough to launch a 15LBS+ rifle off a bench but did not change elevation.

No effect, here is a video I took of my tripod, and you can see Doug's position in front of me. In fact my tripod was tossed to the ground at least 4x so much I had to place it down if I moved away as it smashed a bunch, includes scars now.

 

[Steel head]

Half a mil? At what distance?

1791 yards

Like I said, one of my mile spots.

 

[LawnMM]

Missed the range, still sounds like a lot

 

[Lowlight]

5 MPH being .5 mil difference

Sounds like an excuse for bad dope or poor shooting

We shoot a mile all the time and a 5 MPH change is nothing. We average 6 to 12 on any given day and I don't mean 6 or 12 but 6 to 12 and our dope is consistent.

During the gathering event I shot my 224V to a mile second round impact with a third round follow up hit and my dope was spot on. Wind was easily 8 if I recall with occasional gust to 15

 

[LawnMM]

5 MPH being .5 mil difference

It was easily 8 if I recall with occasional gust to 15

A 1.5 Mil variation?! ?

 

[Lowlight]

Nope walked over to my car, opened TRASOL read the number walked to the line, Laid down, shot and hit with the same number as in my phone

 

[LawnMM]

 

[Steel head]

5 MPH being .5 mil difference

Sounds like an excuse for bad dope or poor shooting

We shoot a mile all the time and a 5 MPH change is nothing. We average 6 to 12 on any given day and I don't mean 6 or 12 but 6 to 12 and our dope is consistent.

During the gathering event I shot my 224V to a mile second round impact with a third round follow up hit and my dope was spot on. Wind was easily 8 if I recall with occasional gust to 15

That’s what I often get.
I’ve shot there about a dozen times this year and it’s been consistent using flags and a kestrel.

What the wind is above us shooting along that canyon I have idea but if I read the flag and kestrel and they’re jiving with about 5ish mph wind a I make the adjustment I’m on target.

Hell, the reason I’m consistent there is because I learned from you the bullet doesn’t lie.

I mapped out impacts compared to wind conditions as what my ballistics app said wind calls should be was not enough.

With that and my trued ballistics app I’ve had a few days with a %40 hit rate there.

 

[Dthomas3523]

That’s what I often get.
I’ve shot there about a dozen times this year and it’s been consistent using flags and a kestrel.

What the wind is above us shooting along that canyon I have idea but if I read the flag and kestrel and they’re jiving with about 5ish mph wind a I make the adjustment I’m on target.

Hell, the reason I’m consistent there is because I learned from you the bullet doesn’t lie.

I mapped out impacts compared to wind conditions as what my ballistics app said wind calls should be was not enough.

With that and my trued ballistics app I’ve had a few days with a %40 hit rate there.

Bullet doesn’t lie, but the reason it’s happening is what’s in question.

 

[Steel head]

Bullet doesn’t lie, but the reason it’s happening is what’s in question.

I don’t know what’s going on as it crosses that canyon but it’s repeatable with visual and measured readings at the target and shooting position.

 

[KYpatriot]

I don’t know what’s going on as it crosses that canyon but it’s repeatable with visual and measured readings at the target and shooting position.

If, and its a big if, your ballistic calculator is set up properly and your zero is good its probably a vertical wind created by wind effects flowing over the terrain. Think about what water would do flowing over that kind of terrain if it were on a river bottom.

99% of the time for me such problems have been from a setup issue, or I created a zero change by the way I was holding the rifle different than when I zeroed.

 

[antithesis]

What is the temp over that "canyon?" Is it some big temp swing where the bullet is flying in much cooler air than the shooting position?

 

[Steel head]

If, and its a big if, your ballistic calculator is set up properly and your zero is good its probably a vertical wind created by wind effects flowing over the terrain. Think about what water would do flowing over that kind of terrain if it were on a river bottom.

99% of the time for me such problems have been from a setup issue, or I created a zero change by the way I was holding the rifle different than when I zeroed.

I’m sure there’s sone wind effects from terrain.
The elevation drops rapidly and then raises back up along the flight path at that spot plus there’s multiple gullies and other features in that area.

I’m 100% confident in my app being true, it works in the multiple areas where I shot and I’m well practiced and confident in my ability to make the shot.

I often shoot with someone who did this stuff professionally for a long time.
He’d love the chance to talk shit.
I don’t give it to him.

All I’m saying is in that spot when we observe and measure a certain wind we get a certain drift thats more than apps or kestrels predict
My 260 gets it.
My buddy’s 338 norma gets it obviously to a lesser extent.
My newer shooter buddy with a 6.5CM gasser really gets it.
It occurs fairly often there and it’s repeatable and documented.

What is the temp over that "canyon?" Is it some big temp swing where the bullet is flying in much cooler air than the shooting position?

The river bottom is often quite a bit cooler.

My bullet path is 3/4 to near the top of the valley.