Doping the Wind, Mirage is Your Friend

[stokesrj]

One of the most difficult skills to master in long range precision shooting is learning to accurately dope the wind. Mirage can help you see what the wind is doing all the way along the intended path of your bullet.

So how do you go about doping the wind using Mirrage? It's a lot simpler than you might think. Using any other method you must know the wind velocity, the wind angle to the path of your bullet and how far the bullet will be deflected by the time it arrives on target. Using mirage, you needn't know the wind direction because the mirage provides the effective wind velocity, which will be the force acting upon the bullet as it travels to the target.

To read mirage, it is best to use a spotting scope although in a pinch some rifle scopes are good enough to read the effective wind speed by the mirage, most are not. The spotting scope also has the advantage of a narrow depth of focus which means you can read the mirage at intervals along the bullet path by focusing at say 200, then 400 and then 600 yards. This can be important because it is unlikely that the wind will be constant the entire path of the bullet.

To read the mirage, focus the spotting scope on the target and back off by 1/4 turn of he focus ring. If the target is 600 yards away this will result in a focus on the mirage at 300 or 400 yards. So now that you see the mirage at that distance, what does it mean?

At wind speeds below 4 MPH the mirage will rise but be tilted by the wind in the direction it is blowing. A 1:00 or 11:00 mirage will mean a 2 MPH effective wind velocity. It may be blowing faster than 2 mph but at an angle to the flight of the bullet other than 90 degrees but the effect will be the same as a 2MPH wind at a right angle to the path of the bullet. A 2:00 or 10:00 mirage will indicate 3 MPH effective wind and at 4 MPH the mirage lays over and flows at 3:00 or 9:00.

Above 4 MPH and to 14 MPH the mirage will continue to flow horizontally at 3:00 or 9:00. Now the frequency of the undulations will reveal the effective speed of the wind, at 4 mph it is a gentle wave and at 14 mph it is a flat line. Experience will help you learn to estimate the speed by observing the frequency of the undulations.

The best way that I have seen to learn to estimate effective wind speed by observing the mirage is to place several buddies beside you with spotting scopes. Have them watch the mirage and at your mark have them all right down their estimation of wind speed. Learning can proceed faster with a wind meter placed down range, but if that isn't available the next best is a proven, experienced wind reader making a call for everyone else to compare to.

It takes a while, it took me about 3 years, but before long you will be able to glance at a wind through your spotting scope and declare it a 1.5 minute wind or a 3 minute wind by knowing the effective wind speed combined with your knowledge of how far the bullet you are shooting will drift at the target distance, given a wind speed and direction.

Hope this helps and isn't too confusing.

[Corjack]

Thanks for this. It is much easier to understand when you can see this at the range. Your write up is easy to understand. Well done.

[trazman]

Thanks Bob. It is really hard to understand wind. You need years of practice which you for sure have...

[Saugmann]

Great post thanks. Can't wait to get up and running again so I can put some of this knowledge into practice.


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