Effect of headwind on verticall?

[baydawg]

Shot in a 12-2 fishy head wind at about 12-15 mph. Was shooting next to a pretty hard holder and we were beating the x ring up. However, there were two shots that we both lost (targets looked like copies) that came up as 11 o'clock 8's.

He was shooting a service rifle and i was on my 223 space gun. Could the headwind have caused some vertical to this extent?

 

[Erik Cortina]

What distance?

 

[spclark]

He was shooting a service rifle and i was on my 223 space gun. Could the headwind have caused some vertical to this extent?

If @ 600 yards & if it was breezy enough (10 mph +) then yes. Fishtails from ahead or behind are some of the trickiest conditions to gauge.

By chance were you at a range where the firing line slopes away quickly facing the targets? Two ranges I've shot at (Milan, IL & Winnequah / Lodi WI) are like that & when the wind's from 10 - 2 & gusty I've seen this happen fairly often.

 

[dcali]

A headwind won't cause an 8 at 600. That was just coincidence.

 

[baydawg]

600 yards eric

 

[Canadian bushman]

Just a headwind makes small deviations in vertical.

A fast headwind flowing over terrian ( burms or hillsides ) can throw substantial elevation into the mix.

 

[Bryan Litz Ballistics]

A headwind won't cause an 8 at 600. That was just coincidence.

^ Best answer IMO. If you both had high 10's, or inside 9's at the same time, maybe. Pushing to the 8 ring is a big deflection at 600 even for .223's. I highly doubt this was wind effect, unless the gust pushed your hold when you broke the shot.

-Bryan

 

[baydawg]

Thank you

 

[wolley]

Just for grins I ran this through JBM at 1000 yards. Berger 168H at 2920.
Wind at 0mph, 0° 299.5" drop
Wind at 10mph, 0° 301.5" drop
I trust JBM implicitly. Too many times I have run loads through this and based on a 100 yard zero, taken the rifle to 1000 and put on the JBM calculated dope and been in the 10 ring.

 

[broncman]

I RRREALLLY think terrain and berms at most ranges show their ugly heads with head and tail winds. A gust or gradient to the wind makes it worse.

Oak ridge has tall berms at 900-1000 and 0-200. I lost so.e vertical points today by not paying attention to the 100 yard flag and 1000 yard flag.

 

[Steve Blair]

Wind alone would not produce that but, as previously noted, wind and terrain will. Try shooting on this range in a tail wind. The 600 yard berm is over forty feet high and will raise hell with your vertical.

 

[Heman]

I RRREALLLY think terrain and berms at most ranges show their ugly heads with head and tail winds. A gust or gradient to the wind makes it worse.

Oak ridge has tall berms at 900-1000 and 0-200. I lost so.e vertical points today by not paying attention to the 100 yard flag and 1000 yard flag.

Almost made the trip down this weekend but didn't kinda wishing I did. But if you talk to Bill Vaughn he will tell you pretty much what Bryan has said the elevation shots at Oak Ridge are due to poor shooter mechanics. It could throw you up to a high 10 or tight 9, but if you're up in the 8 ring you did something wrong. Having shot there before on 90 degree days the mirage soup can cause vertical also.

 

[broncman]

I think "poor shooter mechanics" often is inattention to the terrain characteristics!

I here so many people at Oak Ridge complain about an unexplained vertical. Watched the eights out the top and not know why. I am no expert and I loose my share of vertical...but!

I have not lost one in my last several matches that I did not know why! (Every time i have lost a vertical point, i have missed a headwind or tailwind call) Do a google search of the altitude and plot it for the full range. Head and tail winds at Oak ridge WILL have a vertical component as well due to the terrain.

I video taped most of the match this weekend. Yet to watch it but I will just about put money on it when almost the whole line had a vertical loss, that the flags will show a head or tail wind somewhere on the range.

Another thing you see at Oak Ridge. Sling on the left, F on the middle to right side. Slight differences in the range there too.

 

[broncman]

Oak Ridge elevation profile.

 

[Heman]

Sir I don't want to get into an argument but I have shot on the right side and there is very little different there as to the left. If you talk to Thomas or Phil Crow (Reigning Wimbleton and Leech Cup champs) you won't see them loose high 8's due to wind. Also I have been down there when Danny Biggs and other F-Class shooters have shot some very nice scores. While the elevation profile does look impressive it is not as sever as you think because the bullets are flying above a lot of the potential turbulence. I too have lost elevation shots there which I assumed was the wind, but like I said looking back on it it wasn't the wind it was due to my follow through. When I get home I will run this range with the Navier Stokes equation and you will see it is not what you think it would be, will post later this evening.

 

[broncman]

Not trying to start arguments either, all is good . Yes I have watched the same shooters you mentioned as well. Their technique and wind skills are the reason they are all champions.

School me here if I am wrong, on a F class target at 1,000 yards, from the center of the x ring to the edge of the 9 ring is only 10" . For a common FTR bullet such as the juggernaut, a missed wind call of 1.5 miles an hour and you now have an 9. Two mph and depending on your ability to hold steady, you are an 8.

I easily believe there is wind at Oak Ridge that has 2 MPH vertical component to it.

Not up to speed on how much on the prone target and NOT wanting to start a prone vs f class argument.

Really just wanting to have a good discussion on this and the real possibilities.

Have I missed something on my above math for the F class target?

I may be wrong and probably am, but really trying to get my head wrapped around all this. When you only have ten inches from the middle of the x to an eight , lot to think about.

 

[Steve Blair]

Have I missed something on my above math for the F class target?

I may be wrong and probably am, but really trying to get my head wrapped around all this. When you only have ten inches from the middle of the x to an eight , lot to think about.

[br]
I don't think you are wrong. Yes, the LR target is more forgiving than the LR-F. A good wind reader can mitigate range-induced vertical effects in a head or tail wind by carefully avoiding gusts and let-offs. I usually shoot long range at Camp Pendleton Range 117. It almost always has a ±15° rapidly switching headwind up to about 20 mph. The range is only ~6 miles from the Pacific. Berms are placed at 100, 200, 300, 500, 600, 800 and 900 yards. It is like a riffle box and induces considerable turbulence, resulting in often unpredictable vertical. On the F-Class target, it is more than enough to drop points. Only one F-Class clean has been shot at 1000 on 117.

 

[Heman]

Ok first I will say I was thinking 8 ring on the regular LR target not F-Class. But anyways lets take a look at the range. There isn't Lidar data of Oak Ridge so using the best elevation data I got.

Here is Oak Ridge along with some of the surounding area. Where you see the point saying not defined is roughly around point 10 on the 1k berm

The maroon line is roughly tracing the path to the impact berm and stops on the back side of the butts. You will see the swirling that comes in off the mountain in the back that causes all the wierdness on the 300 and 200yd flags.

Here is the look at the cross section of the wind

Please not the smoothness and lack of any vertical wind. At the target area you do get a little swirling but it isn't coming off the 900yd berm.

Just to check lets do the same thing off the ridges to the south

Now we take a cross section

Notice the more severe uplifts and down drafts that occur well beyond the target carriers.

This was simulated with a 10m/s wind (22.13mph) with less wind you will get less effect. While the elevation plot is impressive you are only talking 40feet in change. If we were shooting over one of the ridges then yes we may notice something. Hope this helps a little.

 

[dcali]

That might be the coolest thing I've ever seen on this site. Thanks. Am I reading that correctly in that it appears that unless you are shooting right over the peaks of the ridges (within a couple feet of hitting them), then the vertical wind component appears to be quite small?

I feel like you're about to get a bunch of requests to analyze various ranges around the country...

 

[Heman]

You would be correct.