Quest for precision 2 -Wind, Light and Mirage
As I write this, the rains and wind from Florence pelt my home in the foothills of NC. I will get some reloading done this weekend. I will leave my techniques for loading in Part 3. I want to discuss the effects of Wind, Light and Mirage and how it affects POI (point of impact).
As the picture shows above, wind flags can tell us what direction the wind is blowing downrange. So often I see a shooter wet his finger, hold it up and make his wind call. That wouldn’t do you much good in the conditions that are shown above. There are a number of pieces of equipment that can measure wind, but much like the finger method, it only tells you what is happening at the device.
So what is the secret of making good wind calls? Practice, practice, practice. Make some simple homemade indicators, take them to your range and place them every 25 to fifty yards. Record what the wind is doing at different distances and the effect it has on your shot. Don’t rely on your memory – write it down.
You can buy wind flags like this one. I find them a bit pricey to have the amount I like to use.
A simple 3-4 foot piece of 3/4″ PVC with a nail attached to the bottom and surveyor tape to the top makes for a great indicator.
Remember mirage is your friend, not your enemy. Mirage is just like a wind flag and can tell us wind direction and speed at your target. This is an excellent illustration of typical mirage on a calm summer day. Note what you see vs. where the target actually is.
All of the pictures I have chosen for this article have come from the archives of Accurate Shooter.com’s Bulletin. I am a member there and it is an excellent source of information. This graphic shows how to read mirage to indicate wind direction and speed.
Once again, keeping a log book gives the shooter a reference to compare the present shooting situation with similar situations recorded in the past. (Are you seeing a theme here?)
OK, here is where we get less factual and more theoretical. I wish I could quantify the effect of bright sunlight, or lack thereof, and POI with a number or a formula, but I can’t. What I do know is that bright sunlight tends to push POI down. Allow me to give this example; you are elk hunting on a ridgetop. The sun is up and you are bathed in bright sunlight. You notice a nice bull strolling through the shaded valley below. You range him, allow for the angle of the shot and hold behind his shoulder. Upon firing you see the bullet splash and realize you have shot over his back.
Another good example would be shooting under cover at the range, shaded at a precision target 300 yards away. The target is in sunlight. You look at the mirage, no wind and notice the heat waves are going to push your shot up about 1 MOA. You allow for that and shoot high, right where you dialed the scope. Why?
The sunlight pushes your POI down, the mirage pushes it up thus canceling the effects of each other. It’s much like trying to spear a fish under water, the target is not where you see it. If smoke is coming out of your ears yet, don’t worry. Mine are still a bit tender from it and I have been working on this close to a year. It’s a wonder I have ever hit anything!
Recently, I shot with a couple of friends at my home range. Perfect conditions, overcast, little to no wind, light mist. I bore down and managed to shoot an unbelievably tiny 5 shot group at 100 yards.
That measured .047″. The following week I shot in bright sunlight, light wind, and medium mirage with that same load and could only manage a 5 shot group that measured .268″. I am still learning and trying to improve my skills. I find that shooting behind my rifle instead of beside it improves my shooting considerably.
The take away from all of this is that this – is the most important tool you have for consistent, accurate shooting.
Precision, Accuracy and Reloading are my passions. Love to hunt, fly fish and read sign.