Where on Wednesday twenty five: Decreasing wind uncertainty

You find out the strength of a wind by trying to walk against it, not by lying down. - C. S. Lewis

I like this saying. It sort of means that only in standing tall and facing things can one confront them, understand them and overcome them. Me likey. Anyway, that's not what this post is about...

As a long-range shooter I'm always chasing accuracy; It simply doesn't make any sense to go to the amount of effort required to shoot at long range only to miss one's target be it a steel sporting target, an animal or targets that one might find in a military or law-enforcement scenario.

Many elements have to come together to shoot accurately: Ammunition quality [I make my own], weapon-system set up [rifle and scope], shooters technique, determining range, reading the environmental factors, ballistics data or data on previous engagements [DOPE], spin-drift, aerodynamic jump, aerodynamic and mechanical properties of the projectile, barrel harmonics, coriolis effect and much more. It's complicated.

Sending an accurate shot to 1000+ metres is much more difficult than it looks on the movies and a great deal of science goes into it.

Fortunately I have spent a lot of time working on the science of it, understanding the concepts and putting them into practice. I shoot accurately to 1500 metres [1640 yards] with a hit-percentage of around 90% give or take a little; I'm a good shooter and have the best equipment and training. I practice a lot too. Why? Because I want to.

So, a lot comes into play in long range shooting...But all that effort can go to waste if one is unable to perform one of the most basic of elements; Basic, yet incredibly difficult to master...Calling the wind; Speed and direction.

Wind affects accuracy obviously, the hit-percentage, so it makes sense that improving ones' ability to accurately call wind speed and direction will improve the outcome. The best situation is to eliminate wind uncertainty altogether however in the field that is not possible, so one needs to increase the ability to accurately determine the wind - A skill I practice a great deal and am pretty good at. [Not ego, just fact.]

I call the wind at somewhere around +/-1 mph which is considered excellent. Sure, I'm not always right, but I'm right enough times. A novice shooter may only hit +/-3 mph accuracy in wind calling. But what does that mean to the shot?

To demonstrate allow me to use the .308 Winchester calibre in a rifle/ammunition combination that shoots at 0.5MOA in accuracy at 100m with a standard deviation (SD) in muzzle velocity (MV) of 10 feet per second (FPS). Let's also use a standard human-chest-sized steel target.

In a zero-wind environment it shoots at 100% hit-percentage, meaning all rounds on target.

Add +/-1 mph of wind uncertainty and some of the shots miss the target. An 87% hit-percentage is gained. Just with the wind call being inaccurate by plus of minus 1 mph! Remarkably with a +/-2 mph wind uncertainty that percentage drops to only 55%...Certainly not acceptable.

Interestingly, a +/-3 mph wind uncertainty only drops hit-percentage down to 42% - A pathetically poor accuracy and certainly bad enough to make the shooter not take the shot.

It is pretty clear that learning to call the wind expertly is critically important to accuracy.

As a novice shooter some 28 years ago I was pretty clueless - I didn't know I was clueless at the time but the more one shoots the more one comes to know how much one doesn't know. As my demand for accuracy, improvement in hit-percentage, grew so did my appetite for the knowledge and understanding that would improve it. So...I started learning, not just shooting.

But how did I learn the wind? It was quite simple really...I just grabbed my Kestrel Meter [an environmental meter that measures altitude, humidity, the wind, latitude, temperature and wind [among other things] and started reading the wind...Everywhere I went.

I'd look at the trees and call the wind then check it against the Kestrel...Over and over again. I'd look at the dust, sand, paper or leaves blowing, flags on poles, grass, wheat, wheat-stubble, cows tails, horses manes, waves/water on the ocean and lakes...Literally anything that was moved by the wind. Slowly I became better at it.

From there I recruited other people...Mates also learning the wind, my wife Faith, whomever agreed to come with me. I'd equip them with a CB radio and my Kestrel Meter and send them downrange a kilometre (1000m) and I'd stay back looking through my rifle scope at trees and things calling the wind downrange getting them to call back the actual speed to me. They'd kick up the sand or dirt, throw handfuls of grass in the air, even just stand with loose clothing on so I could call the wind as it blew. Once my proficiency improved I sent them further away and practiced some more.

I even started calling the wind from the mirage I saw through my scope. A mirage boiling vertically indicates no wind. A slow-mirage, say 30° means 1-3 mph, 60° some 4-7 mph and a fast mirage at 90° some 8-12 mph. Of course there's other factors here and mirage is always verified with other wind observations.

I'm pretty good at it now, but like a top pro golfer I practice my swing so to speak...Over and over. It keeps my wind calls sharp and at a high level of accuracy. A note...It's very important to observe how the wind affects different things...A gum tree will behave differently than a palm tree, wheat crops differently to winter grasses etc.

Just a word on calling wind over distance. I've shot over terrain where the wind is going in one direction at say, 300m, the opposite at 700m and opposite again at 1000m! In this case each wind call is averaged out to provide an acceptable wind call. Swirling wind is very challenging but with practice it is still shootable. The wind has the greatest affect on the projectile at greater distance as the bullet slows nearer the target so that's the wind call to get most accurate, and the one I lean to in this difficult situation.

Anyway, this is getting long!

Wind typically brings the greatest uncertainty in long range shooting and causes the most misses; Higher-performance rounds like the 300 Win Mag are affected much less, but are still susceptible and the requirement to call the wind speed and direction accurately is always a necessity when shooting at long range.

Over the years I've studied the effect of the wind on my long range shooting, analysed the results in many different situations and recorded the data, the DOPE. This enables me to take shots now with the minimum of fuss and maximum hit-factor which, for a shooter in any circumstance, sporting, or in a military or law enforcement application, is critical to operating at a high level.

Aim small miss small, but get the bloody wind call right!

Thanks for reading.

---

Tomorrow isn't promised - Design and create your ideal life, don't live it by default Discord: galenkp#9209 🇦🇺

Images show my custom cerakoted 6.5mm Creedmoor long range rifle. You will note a red and black band around the base of each round...That's the marks I add when I make them to identify them against other shooters' cases. (I collect them after firing for reloading).

_{Some data has been lifted from Accuracy and precision for long range shooting by Bryan Litz.}