TargetTalk

Is there such data out there? Basically, even if I know the direction and velocity of the wind, how do I know how many minutes to correct for at 50 and 100? Experience?
Thanks.

Yep, experience is the most important bit. That's what your sighters are for. Do some wind-doping - leave the sights alone and shoot in both the lulls and gusts, see how far they push your shots out.

You should know how many clicks per ring your sights need.

Standard advice is to sit and watch the wind before your detail. Try and spot the average wind condition - do the flags spend most of their time at 7 o'clock, 8 o'clock?

Pick a condition and zero to it, then only shoot when the wind is right (this is not necessarily the quietest condition - it's the most consistent). Obviously if you start running out of time you'll need to shoot through the wind, which is where the wind-doping from your sighters comes in handy. If it picks up from a 7 o'clock to an 8, you'll know roughly what it's going to do to your fall of shot and can adjust your sights appropriately.

To actually attempt to answer the OPs question: windage values are about 2.0 MOA at 50 yards and 4.0 MOA at 100 yards. Note these values are rough and can vary as much as 10% on muzzle velocity alone. You would expect the longer distance to have more wind, but as it turns out .22s maintain about 85% of their muzzle velocity at 100 yards, so drift is very roughly linear...

-Mark

msnation wrote:To actually attempt to answer the OPs question: windage values are about 2.0 MOA at 50 yards and 4.0 MOA at 100 yards. ...
-Mark

For what windspeed- 10mph, 100 mph?
What direction?

Your attempt at an answer doesn't really answer anything...

I think where the OP is coming from is what we used for fullbore, a target plot sheet marked in squares of MOA. So for instance if you estimate a 2 minute wind from the left with the old 4 click to the minute sight you wind across 8 clicks or what ever for 6, 8, etc click per minute sights, so you need to know the clicks per minute of your sights first to be able to adjust accurately. I don't know of any such plot sheet for smallbore
But that's the easy bit! In practice you need to be able to read what strength and direction the wind is and its effect on the shot placement, that's the difficult bit and where the black arts come in! I agree with Hemmers, its all about experience, if its a gusty day, get out there, practice and experiment.
Good shooting
Robin

Try this link for some basic info. on wind drift. As winds are seldom constant or kind enough to only come from 90degrees left or right, experience is still the best. Regardless, it's interesting reading.

http://www.gunsmoke.com/guns/1022/22drift_cross.html

For what it's worth, if you know the displacement for a wind speed at 90 deg to the line if flight then the values for the following angles off are:

15 deg - 25%
30deg - 50%
45 deg - 75%
60 deg - 90%

The more discerning will have detected that the above values are suspiciously similar the the Sine of the angle off and if you assumed that the effect on the velocity was proportional to the Cosine you may well be correct!

However as was said earlier, work out what the wind is doing beforehand, confirm it on the sighting diagrams and then proceed with careful observation of shot and conditions.

Rutty

Sorry, that's 2.0 MOA at 50 yards and 4.0 MOA at 100 yards for a 10 MPH full value (90*) cross wind. These were calculated from ballistic coefficient data supplied by Lapua. Using the angles that Rutty noted, a solution can be estimated for various wind speeds in various directions.

Most smallbore shooters don't have sight that can keep track of windage zeroes, so these numbers are mainly a comparative tool ie. given a particular condition change, you can estimate how far out it would put you and therefore help you better establish what an 'acceptable' condition looks like on any given day and time.

Sorry about the confusion!
-Mark

BarryB wrote:Try this link for some basic info. on wind drift. As winds are seldom constant or kind enough to only come from 90degrees left or right, experience is still the best. Regardless, it's interesting reading.

http://www.gunsmoke.com/guns/1022/22drift_cross.html

Throw in the variation in wind flags between ranges, whether they are wet or dry and if they are new or have some age on them and experience on the particular range during the training sessions is the only real guide.

Thanks all. I know there is no substitute for experience, but knowing the math is often a good starting point.

I know what you are looking for. A small booklet of piecharts with each page at a different range. I have one in .308 for highpower for the 168gn bullet. I can't find anything like it in 22.
Practice and experience is the key. My 15 year old shot a 100yd Palma last weekend. The wind was horrible. It was generally in our face gusting from 20-30 mph. It would suddenly switch to 3 to 9 oclock. The other problem was 6' steel baffles- three of them to prevent overshoots. The windflag was downrange of the baffles- bad idea and the slanted baffles turned the horizontal into vertical.The winner was my son's coach with a 446 with eons of experience. On a calm day my son could possibly shoot in the 440's but he had to deduct at least 100 points due to his inexperience. His coach found a condition to shoot in. My son burned his targets after the match. Good lesson
Chris

RobinC wrote:I think where the OP is coming from is what we used for fullbore, a target plot sheet marked in squares of MOA. So for instance if you estimate a 2 minute wind from the left with the old 4 click to the minute sight you wind across 8 clicks or what ever for 6, 8, etc click per minute sights, so you need to know the clicks per minute of your sights first to be able to adjust accurately. I don't know of any such plot sheet for smallbore

The problem for smallbore is such a sheet would be black with scribbles by the end of a 60-shot match. Fullbore shoots are typically two sighters plus 7,10 or 15 counting shots, which is manageable. For smallbore you'd have data overload by the end of the match, unless you had 6 sheets per match and turned over to a new sheet for each string or something.

Also, it's a different way of shooting. Smallbore you crack on and someone else worries about scoring it (whether electronic or the cards are manually marked afterwards). With fullbore you're register-keeping for your neighbour anyway, so maintaining a plotting sheet does not disrupt the rhythm of your shoot in the same way it would for smallbore (if the wind had settled and you were trying to rattle through your shots quickly whilst the going was good for instance).

Hemmers
Yes, I do agree, totaly use less for smallbore. There is no alternative for experience, and you get experience by practicing and takeing every opportunity to shoot in windy conditions.
Practice brings confidence and in wind you need to be decisive.
Good shooting
Robin

just read up on wind reading. Its really not that confusing. but it can be interesting.

This is what I do for a NRA 1600 match:
I get to the range about 45 minutes early and begin setting up my equipment on the line. While setting up the equipment I am looking at the flags. I am seeing what the highs are and what the lows are. I also look to see if it switching direction. if so how fast?

When I put out my target I look to see if the wind flag will be in my way and i move it if it will be.

When I set up my scope I set it up looking at my target and focus it on the target. I then back off the focus about 1/6 turn so I can see the marage (if there is any).

When I begin shooting I know what the conditions will be on avg. I then get sighted in while in the predominent condition. I then begin my target.

If during my target the wind changes a little bit i have four options 1. Wait 2. Click the sights 3. Shade 4. go back to sighters. It depends on the wind switch as to what I will do. If it is a small change I will usually shade the shot (if I am confident in the wind value). If it is a big switch (90 degree swich for example) i will wait. If it doesnt want to go back my condition I will go back to the sighter.

One thing you have GOT to do is watch the mirage. It gives you way more info than the flags do. one example is at camp perry. The mirage at perry is very easy to read if the sun is out. it is equally ammusing to watch people who dont look at the mirage. I was shooting this summer at perry and it was the 100 yard stage. I was watching the flags and they showed that it was my condition. I looked through the scope and the mirage in front of the target was slowing down a little bit. the mirage BEHIND the target had flipped directions. So I shaded and shot an x. I looked at the targets next to me and saw they had all just shot nines.
Matt

If you use a ballistics program like "Simple Trajectory Program" which is a free download you can put in wind speeds and directions and get the amount of drift that can be expected with a given rounds BC/Velocity etc. It is more for scope setups but drift is drift no matter what the setup once the bullet leaves the barrel.

Of course these are hard coded numbers and the wind is seldom so steadfast but it gives you a good idea of what you could expect. Knowing this along with the true windspeed at the given moment is very useful info when dealing with wind out past 50y especially.

As someone above mentioned when you can get the full value drifts committed to memory you can easily adjust to 1/2 and 1/4 value with easy math in your head.


Bo