Wind Doping Basics
Wind has two distinct identifiers that every rifleman must be familiar with. The first is wind direction. We evaluate wind direction by the clock system. Each direction will have its own response. Once we learn those reactions we can look out for them and react accordingly.
The flags show confusion. Turmoil exists. Wait it out!
The second identifier is wind velocity. That appears to be easy. You hold farther out as the wind increases in velocity. Guess again! You now have to combine direction with velocity to obtain a proper response. It would appear that the pair of problems should be easy to unravel. “Not so!” says the wise man. By combining forces, wind direction and velocity double up on us to make life even more difficult. In some situations mirage also will enter the picture. This bad boy often is viewed as another culprit. I will devote some time to mirage later.
We are going to start our lesson on the range. Go to your favorite 100-yard range and put up some targets. Now put a wind indicator near your targets. If you never used one before, now is the time to start. Steal a light piece of 1/4-inch seam binding from your wife’s sewing box. Some bright colored knitting yarn works well too. Find a 3/4-inch piece of surveyor’s tape. Avoid anything that is heavy for it will be slow to respond to small changes and will be useless when wet. Mount your wind indicator on a rod with a 90 degree bend at the top. You want the indicator to hang free below its support. What you want is something that will alert you to changes in wind velocity and direction.
The condition has reversed from a 9 o'clock wind. This 3 o'clock wind will put your shots out the left side.
Benchrest shooters resort to some rather elaborate mechanisms to read the wind. Looking out over a benchrest range is like viewing a massive field of mechanical flowers as they bob and weave about in an attempt to unlock for you what the wind is doing. I have a set of three stands with wind indicators on top. These indicators include a large daisy wheel that spins ahead of a tall blade, a large ball and blade device that looks like a miniature weather vane, and a smaller ball and blade with surveyor’s tape dangling off the end. All of these devices are mounted on roller bearings that do not impede the rotation of the indicators. You do not need anything that fancy at this point. That simple strand of yarn will tell you much. Just be sure to use it.
As you test loads or practice reading the wind, pay attention to the direction of the indicator. Try to shoot when it is blowing in the same direction and exhibits the same angle. As an example, we will use an angle of 45 degrees from the left side of the target. Break every shot when that flag is in the same position and you should have a nice group. Shoot one when the flag drops straight down and you will have a shot out the left. Shoot one when the flag rises to horizontal and you will have one out the right. In the simplest terms, that is how to read the wind. Unfortunately, it does not always remain simple. A few examples are in order.
If that flag indicates 45 degrees as you watch it rise, your shot will impact at one point. Take that shot on the flag as it drops to 45 degrees and your shot will go to a different point. Both were fired at 45 degrees. The first shot was on a rising flag, which indicates an increasing velocity. The second shot was on a dropping flag, which indicates a decreasing velocity. The difference will be very small, for both flags indicate 45 degrees as nearly as we can determine. You will see a difference.
Granted, that difference will be miniscule for the purposes of varmint shooting. A benchrest shooter might need that difference to win the aggregate for the day. Is that picky? Yes! Is it necessary? At times, yes it is!
Another set of flags will show a wind from 5 o’clock at a given velocity. You shoot a few shots. A bit later the flag will switch around from 11 o’clock. The angles are 180 degrees opposite and off the centerline by the same amount. The uninitiated might figure that the bullet impact will be similar. The ones from the 5 o’clock flag will strike higher, and more left, than the ones from the 11 o’clock flag. The wind from 5 o’clock will lift your bullets up and left. The wind from 11 o’clock will push your bullets down and right. It may be less than 1/8 of a bullet diameter or much more than a bullet diameter, depending upon wind velocity.
Now multiply that by all 360 degrees that form a clock face and factor in all the wind velocities that are possible. You will surely see the complexity that wind doping presents. These sets of conditions can be figured out nicely on flat land. Things change when we add the contours of a range on a hillside or a long rolling meadow full of varmints. Another set of variables now enters the picture. The wind going up the hill will do one thing while the wind going down the hill will do something else. Now change the clock position. Are you going nuts yet? Mix this condition with wind direction and velocity and watch the challenge build.
Something is about to happen. The flags say you should wait. Listen to the flags.
Time spent on the range will reveal just how subtle the wind can be. I often suggest to new shooters that they spend some time just watching the flags as they move about. Don’t try to shoot through this until you have a little idea of what can happen. Watching another shooter would be good. Once you get the idea, go ahead and try to figure it out. I can guarantee you that it will be one of the quickest, and most effective, lessons you ever take as a rifleman. If you can make it work you will gain confidence. If you do not get it right, humility will enter your life. Keep at it until you begin to see progress.
Way back in 1979 and 1980, I organized and ran a benchrest school for IBS. This three-day school featured many things relative to the sport of benchrest shooting. The segment of the school that brought the most comments was the time spent on wind doping. I was amazed at how excited the attendees were about what they learned during that session. They knew that it was important if they wanted to win. As I was writing the article I called Bill Creasy to see if he is still making the wind flags I use. Unfortunately, he is not. While we were chatting, he told me that he also had conducted wind doping sessions for IBS on several occasions. His remarks duplicated mine in that his students were deeply appreciative of the information they received relative to reading the wind. Truthfully, it is the area of shooting that plays the most havoc with good groups. We obtain good equipment. We develop great loads. We have confidence. Then the wind blows! Now what do we do? I will let you in on a little secret. Benchrest matches are won by the shooter who is the best wind doper on any given day. It is that important!
There are several avenues to take. Way back in the 1960s when I was just a beginner in the shooting game we had a wind chart. That chart, which I am unable to find anywhere, revealed that the winds from 2 o’clock to 4 o’clock and from 8 o’clock to 10 o’clock were full value winds. For that we could make corrections. From 11 o’clock to 1 o’clock and from 5 o’clock to 7 o’clock the winds were listed as being of one-fourth value. For these winds we would use just one fourth as much windage as for the full value winds of the same intensity. All the rest were half value winds that carried just half the corrections of the full value winds. It served as a guide but we quickly learned that we had to apply some experience to fine-tune it. It was an excellent starting point.
Compare this steady 9 o'clock wind to the one coming from 3 o'clock. Your shots will go out the right side.
I still have my old Master Rifleman Score Book from way back then. In the front there are wind diagrams that show the appropriate amount of adjustment for each target distance. These adjustments are superimposed on a target face and serve the target shooter well. The 200- and 300-yard targets depicted in the book show that the values are close to those stated by the full-half-quarter value description from the preceding paragraph. These charts are for 30-06 and 308 match ammunition as would be expected from a high power scorebook in the late 1960s. These charts are shown in the book to illustrate that the particulars of wind doping can be calculated and diagramed. The wind flag illustrations on the bottom of the page are especially useful. Converting angle into velocity is easy with those illustrations. Now all we have to do is modify them to read in minutes-of-prairie dog and we will have the perfect guide.
The only reference that I have for wind drift is my fourth edition of the Hornady Handbook Of Cartridge Reloading. The wind drift tables give information on 10 mph crosswinds for a variety of velocities and listed ballistic coefficients. To obtain information on your bullet of a different ballistic coefficient you will have to interpolate to find your data. A careful study of these charts would be a good starting point for anyone who is just getting started. Surely you can learn from what is presented and begin to apply this data to a variety of situations as you go along.
<Previous | Home | Next Page >
All times are GMT -5. The time now is 05:31 PM.