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Wind Reading and Scoring papers

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thomasair

thomasair

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Nov 6, 2016
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Colorado, United States
I’m going to post some links below to articles about wind, pellet and slug drift, and target scoring. The more tools you have in your toolbox, the better equipped you will be to perform any task with a good degree of satisfaction. 


This article is about how to boost your FT scores by using a simple system for estimating wind drift. If you read through it and spend the time to put it to practice...you will advance yourself well beyond the normal skill level vs time standard in the game. This info can also helpful for the typical BR game.


http://www.wftfusa.com/training/an-approach-to-reading-the-wind-and-adjusting-windage/



This next link is to a good technical article about how pellets and slugs move in the wind and more. This is written by Bob Sterne. Bob has done a very good job of putting information on paper that is very useful to most, and he doesn’t just talk out of his rear. He takes the time to educate himself before he speaks. This paper will tell you why your pellet or slug goes where it does...assuming your rifle is capable of shooting accurately. You will quickly see why you must have wind flags on a BR range if you are going to have any chance of predicting where a pellet will go without sighters.


https://hardairmagazine.com/ham-columns/vertical-deflection-for-pellets-in-crosswind/



This one is just a paper that I wrote on scoring. It was done with 25m shooting in mind, but applies to scoring targets universally.

https://www.usairriflebenchrest.com/notes-from-the-bench/target-tolerances-scoring/



Hope some find them helpful.



Mike




 
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Thanks Mike.

I'm used to thinking in mils which I got used to doing in Tactical and Field course matches with centerfires and rimfires, and also I used my Kestrel most of the time.

For FT I use a FFP scope with a mil reticle and mil turrets in .1 mil clicks so all I need to do is look at my SHOOTER balistic app and it gives me the drop and wind drift dope. 

As I think back the most benefit I got from this system was at one of LD's matches. It was pretty windy and there were 4-5 targets past 55Y with many shots both uphill and downhill. One target was at 70-ish yards with a 13-ish mph full value wind and it was downhill at 10 degrees. It doesn't feel comfortable aiming that far out, in this case 3.5 mils, but I just did what the app gave for solutions and ended up winning open class in this two day match.




 
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"

There is a piece of information here that is very useful. Note what happens when the wind direction swings around from 2 to 4 o’clock or from 8 to 10 o’clock. The sideways drift hardly changes at all.

However, note what happens when the wind shifts from 11 to 1 o’clock or from 5 to 7 o’clock. The POI shifts sideways a huge amount!

This means it is actually harder to know where to aim in shifting winds if the wind is head on or behind you than if it is from the right or left!"

Ted Bier Also talks about this in his "How he won extreme benchrest" video.

https://youtu.be/TNONcrNmWDE
 
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Mike,

Good stuff, as you have essentially compiled a lot of useful info many non-benchrest shooters were not aware of, and revealed plausible theory on why winds have the effects they do on our shots from the bench at fixed, relatively short range.

The “rose” has been passed around for several decades, but as is mentioned in your post, the results are contrary to what really occurs with airgun/pellet shooting (a fact often not accepted by many experienced airgun shooters).

But, I feel the results you and Bob state with regard to shifts as a result from head and tailwinds are overstated. My experience, and those of many 25M airgun Bench shooters I have questioned, is that direct 12:00 and 6:00 winds do not have much effect, generally still giving the same score per shot, but perhaps turning an X into just a ten.

Bear in mind, a 7mph wind has around the effect of a 10fps muzzle velocity change ... which is not generally considered really a big deal to most competive shooters for 25M BR.

So, when adding or subtracting a bit under 1.5fps per mph of head/tailwind it becomes clear to me why I’ve been able to take advantage while many competitors stop when no colors are showing!

I started shooting airgun benchrest in the olden days in Chino on Larry Brown’s BR50 target. That range, like many, had protection from front and rear, so most of us never experienced true head/tailwinds ... just crazy swirling from the overhead baffles and crosswinds ... but I was also shooting Field Target at several true outdoor venues, and had ample time to sight in from benches. But still, it didn't gel for me until my move In 2000 to my place here in Temecula, when we began to shoot airgun bench rest regularly on my property “blessed” with winds from all directions on any given day, that the “rose” being sagely passed around was mostly useless for us airgunners. We were probably the only club in the country regularly shooting for groups at 50yds with airguns for several years, but we also shot “one shot per bull” targets at closer ranges.


 
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Hi Larry, the wind rose I came up with for pellets was obtained by empirical means with a 12 fpe gun and a standard grooved barrel. I did not come up with it by theory. It doesn’t really apply in totality to all types of barrels and pellets. The effects are present in some degree, however, to every barrel I have ever tested. 


Mike 
 
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Ok Mike,

I can’t say your findings are not what you observed, I only say the head and tailwind effect Depicted in your “rose”, all things being equal Is generally much more than what i have seen, being as the (vertical) shifts you show are very similar to your same chart’s quartering winds. Also, my experiences usually were to see more vertical shift from left quartering winds than downward from right, which seem to not be so for you.

But we are all entitled to voice our opinions equally.
 
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Larry...that could very well be. It wasn’t meant to represent every rifle and pellet combo or be the absolute guide. The knowledge I obtained from the process of learning this has served me well in both BR and FT. In the short amount of time I have shot slugs out of my particular barrel at 100y..they have showed a lot of movement in the vertical plane when the wind moves around the clock. Much greater slant than the pellets.


FWIW....I came upon these results indicated on my wind rose by having 2 benches, targets, and sets of flags set up facing 180 degrees opposite each other on my range. I was able to rule out scope zero error by shooting one way, then the other in the same conditions ....observing the different drifts without having to wait for the wind to reverse. I have listened to guys tell me how “flat” their gun shoots all the time. In reality...they are only shooting one wind condition and they have just unwittingly clicked out the vertical in that direction. They would avoid the wind coming the other way because they got “flyers”. This was at Joes in Oxnard.


Mike
 
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Hi Dennis, back when I did this I only shot a 12fpe rifle. My observations for the 20fpe rifle using monsters since then indicate that it will still follow the general vertical pattern ...but not as much. I call this the slant. The slant is less in a rifle shooting monsters at 20 fpe compared to a rifle shooting 12. It won’t be necessary to hold as low in a left to right. You might call it flatter shooting.


Mike 
 
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Good information. But ifyou don't get flags and use them every time you shoot the information will be of little value to you. I see guys with a Kestral wondering why they don't to well. Number one know the windspeed with no ability to pin direction is wothless. Number two, knowing the windspeed only at the line is equally worthless. What is it going forward to the target. Gotta have flags and use them....always. If your at a match with a good shooter using flags stand behind him and observe when he shoots....and when he doesn't. You will learn if you do it.
 
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