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  wind reading Part 1
« on: August 28, 2008, 11:46:48 AM » by bergerbullets
This topic is one which haunts the novice and experts alike.  it will effect all segments of rifle shooting from minute air rifle/rimfire 40grain to heavy big bore bullets the likes of 750grain Amax.  This makes wind reading a topic of interest to all however the effects of wind are always more pronounced as the distance increases.  On the other hand windreading is one factor that tells one shooter from other, that scores X's on one side and throws bullets completely off target on the other.  It has been studied, taken to war and allied with, however no matter which route you take, the wind is there to stay, and thats a plus..

alright lets go through some basics which can give you some ideas if you are shooting in the wind, then we go to some wind reading tips. 
i'm taking an extract from this article which i believe is very well written.http://www.6mmbr.com/Winddrift.html
Quoting the article: "Note that the deflections at 100 yards are typically a quarter of those at 200; lateral deflections increase as the square of the range". Precision Shooting, June 2000, p. 16. i managed to get a copy of the article and its very interesting however to some it up, 
if you are shooting at 50m, and the bullets hit 2.5cm off your POINT OF AIM(POA) then this will give you some feedback on what the wind is doing.  if you look at your tables, you should find approximately how fast the wind is blowing assuming the wind is blowing from 3 or 9 o'clock(full value). Tables are usually computed for a Full value wind so keep that in mind.

Now if you want to go shoot 150meters you have a preliminary gauge to help you.  if your POI was 2.5cm off then at 150m using the rule of the square you should be
So seems like should be: 150/50 = 3 times the range.

So square that: 3x3 = 9, x 2.5cm = 22.5cm. /2.5 = 9" 
150m=164yds so 9/1.64 =5.5MOA correction

How about trying to gauge the wind ourselves? i read many articles and DVDs on this and very very few do give indications what to lookfor exactly except for that table which they usually give ie: 3-5mph-wind felt on face...etc

alright this table is a guideline but realy its not precise enough. it will always be felt on face from 2mph onwards so how do you quantify? get one of these lowcost wind meters and go out in the garden or rooftop and switch it on.  You don't need expensive ones if you just want a wind meter.  there are many that retail for a low price and are OK for this. i tried silva and it seemed good for this.  THe kestrel is very sensitive however and will mark in tenths of a mile/hour.  One thing about wind reading, FORGET Force 5 , force 4 winds, no table is given in 'force 4' Units.  it is either Miles per hour or meters per second so learn to use that so that you can speak with other fellow shooters in same terms.  I had no indications in meters/second tables so i went with mph and i like it.

Indoors all maltese houses however have an aid that can help you estimate winds.. yes its fan in your kitchen.  it blows constantly and at a particular speed moreover, it has power adjustments and lately mum got on with 5 power settings and i started to tinker with it Wink  standing infront of it at a constant distance(ex30cm) switch on the fan and open your weather meter, give it sometime to settle and write down the force of the wind and what you feel. usually they start around 5-6mph for the lowest power and about 8-9mph for the highest.  Those large fans found in some shops or gyms can go up to 13mph:)yes took the little gadget with me to check..Wink

then you can take the fan with you and place it infront of objects like plants and see how they react to it. some vibrate slowly, some shake violently, however i found a good aid.. its a 24" of ribbon 1"wide that i stuck to a pole infront of the fan to help me get an idea of how it reacts to a particular velocity.  roughly at lowest speed 3mph(i increased distance from fan) the 24" ribbon is about 35degrees from the pole. at 5mph it was about 45degrees from pole and at 7 it went about 60degrees. taking exact photos is difficult because it moves abit up and down but i tried for the sake of  this article. at 8mph this 24" ribbon flat line completely.  now when i go shooting i can stick it out on a branch about half way down range and i can get an informed value based on my little research and hey it works;)))

meanwhile i will also give you some data that i managed to gather but not everything. the rest you have to find out yourself because your body needs to get a feeling for it, so mere words wont do it.  try practicing a couple of minutes a day and i assure you that you will read the wind at your location up to+/- 1mph no joke:)  look through your spotter and try to guess what the wind is doing downrange.  then go there and verify. you can alternatively place the wind meter into the wind and look at the reading from your spotting scope.  dont take it 200meters down range, this is an exercise to use your spotting scope and train your eyes. you will be surprised how sharp you can become and the glorification comes when you can dial in a good wind call and make a hit!ding!

here are some photos;
here are some photos;
3-4mile hour wind about 35deg
the meter here shows abit more because i moved closer to the fan while taking photos!


5mile/hour



6-7mile/hour


8mile/hour/ flat lined ribbon




with regard to definitions i found that
2-3mile/hour is barely felt on face and barely moves your hair and eyelashes.

4-5is felt on face and if you are looking into it the wind creates just a small bubbling sound in your ear that disturbs slightly.(listen carefully and clean your ears;))
5-7 you can notice the trees agitating and moving constantly. some of that long grass will start to tip quite at an angle.
8mile/hour is strong as that of a number 3 on a Fan and will move small plants leaves, move some debree(trap).
10mph is stronger than the fan and if your hair is abit longish, it will move to one side opposite the wind and bothers your eyes abit if you look into it for a constant moment.  the bubbling sound is more prominent in your ears and hanging branches will sway a little.
11-13mph will start to flat line most flags.  NO not those huge ones that hang off the Maltese rooftops, those need a fricken hurrican heh but i dont have one so i dont know what will take to flat line it.a 3feet flag should flat line

anything above 13mph should be moving and swaying the trees and probably you're gonna have a hard time in this wind.
a 15m/hour wind will start to move those cables we have in the streets.  now you have something to refer to but you need to practice.  one more thing, when trying to establish wind velocity, it is very important to establish wind direction and if the wind is constant or gusting.!dont shoot in a gust unless you have to.
enjoy and goodluck.

you don't need to read winds to +/- 1mile per hour to make hits far out but +/- 3 is important.  the flatter (in terms of wind)the caliber you are shooting the better but thats one of the reasons why a 308 will be better suited for 600yard targets than a 223rem and consecutively  a 6.5-284norma(284Winchester necked down to 6.5 shooting 142SMKS) will be them all out at any range. Smiley
rod

« Last Edit: October 13, 2008, 00:15:37 AM by bergerbullets »
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range it, dial it, squeeze the round off.
Certified Precision Rifle Handloader, Basic & Advanced- Russell Simmonds Reloading School - UK

  Re: wind reading Part 1
« Reply #1 on: August 28, 2008, 12:34:10 PM » by RB

...if you are shooting at 50m, and the bullets hit 2.5cm off your POINT OF AIM(POA) then this will give you some feedback on what the wind is doing....

...Now if you want to go shoot 150meters you have a preliminary gauge to help you.  if your POI was 2.5cm off then at 150m using the rule of the square you should be 2.5x3=7.5x7.5= 56.25cm(22") off your POA. translate that into MOA 22/1.64(1MOA at 150m =1.64)=13.4MOAdrift.  this should be a guide line.

The calculations seemed odd, and a bit out... seemed a bit on the high side... so...

Looking at the site suggested,

"For example. if I see empirically that I need 1" correction at 100yds, then I know at 600 yards I need (6x6) or 36 total inches of drift correction, or 6 moa."

So seems like should be: 150/50 = 3 times the range.

So square that: 3x3 = 9, x 2.5cm = 22.5cm.

RB

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The Bright Side: "Sir! We're surrounded!" - "Excellent! We can shoot in any direction!"

  Re: wind reading Part 1
« Reply #2 on: August 28, 2008, 13:03:02 PM » by bergerbullets
RB, i went through it again and you are right on that, i should have noticed, thanks for correcting. i should have refreshed my memory before writing it. eh my profs use to say that, always quote your sources;)
thanks again.
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range it, dial it, squeeze the round off.
Certified Precision Rifle Handloader, Basic & Advanced- Russell Simmonds Reloading School - UK

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