There are plenty of thorough resources out there that deal with beating the wind, so my goal here is not to provide a comprehensive wind doping guide. Rather, I want to address one specific issue that came up recently at my local range. That issue is assigning Wind Values.
Many shooters have memorized or have a quick wind reference guide, either derived from empirical data or software. It’s usually based off of distance and wind in MPH increments. There are different methodologies out there, but a common practice looks something like this:
- Determine wind speed in MPH
- Determine wind direction.
- Using a “Wind Value” guide, get an “Adjusted MPH” (IE…14MPH @ Half Value = 7 MPH)
- Reference that “Adjusted MPH” to the correct distance on your chart.
- Adjust or hold off, and fire.
The Wind Value part is critical, because all the other information is given to you. Aside from determining wind speed, it is the only variable that you must figure out in real time, on location. Everything else is given to you in your data. IE, you have it written down that X MPH wind requires Y amount of adjustment at Z distance.
I’ll start by saying that the traditional clock method is a little bit screwed up. It’s good for getting close, but if your goal is to expend one round and hit one target it is often not good enough. As precision shooters, we should endeavor to eliminate as many variables as possible. While time is often a factor, a little “tactical patience”…taking a few extra moments to set up the shot can pay dividends.
So let’s look at the wind value clock, and why it’s incomplete:
Here is a better way to assign wind values:
MPH X C = adjusted MPH
If wind direction is 90 degrees from sightline C = 1.0
If wind direction is 65 degrees from sightline C = .9
If wind direction is 45 degrees from sightline C = .75
If wind direction is 30 degrees from sightline C = .5
If wind direction is 15 degrees from sightline C = .25
If wind direction is 0 degrees from sightline C = 0
The clock ignores 3/4 and 1/4 values. It can be a little hard to get this precise without measuring devices, but you can do it with practice.
So let’s run a random scenario and see how real the problem is. Most of the time, shooters will call a 1:30’ish wind half value.
Let’s say you’re shooting a MK12 with MK262 at a 600M target. Half of 14MPH is 7MPH, and your reference tells you that this shot requires 1.8 MILS of adjustment, or around 42 inches.
Now, try using 3/4 Value. At ~10 MPH you get 2.6 MILS of adjustment, for 60.3 inches.
This is a significant difference. Let’s now look at the actual answer and see what method got you closer. Plugging the actual environment into a ballistic program (in this case “Shooter,” which I have trued and verified), and by this I mean actually inputting 14MPH and 45 degrees into the program rather than a wind value based on an adjusted MPH…surprise surprise we get exactly 2.6 MILS. In this scenario, the clock method leads to an 18’’ miss, or roughly the width between the shoulders. No-go.
So, the key takeaway here is that if you use a quick reference guide like I described up top for wind, make sure that you do your part and accurately determine value, so that you can reference the correct wind speed and make a first shot hit.
Hopefully this helps somebody.
