READING MIRAGE

 Gene Beggs

What is mirage? In the words of Ed Watson, “Mirage is wind you can see.”

From a shooter’s standpoint, that is the best definition I have heard. Scientific types explain the cause of mirage, but that does nothing to help us on the firing line; here I will tell you how to read mirage.

You may be thinking, “If mirage is “Wind you can see” what is the difference between mirage and wind?”

Wind is nothing more than movement of the air mass; mirage enables you to see it. It is wind not mirage that drifts the bullet.

Picture yourself seated at the bench, ready for the first match of the day; skies are clear, temperature cool and wind is calm. The lightweight ribbons are motionless, the target is crystal clear; from all indications, there is no air movement, and your record shots form a nice group right at the point of aim.

During the second match, wind remains calm, but the target image is now slightly blurred; shimmering heat waves are rising vertically in the scope making it difficult to establish a precise point of aim, and your group prints higher than in the previous match. What has happened is; the sun is higher, shining more directly on the ground, warming the surface. Warm air in contact with the ground is rising, creating what is known as a “Boil.” The rising air causes the bullets to strike high. Now let’s discuss the second level of mirage which I refer to as “Lean.”

Lean occurs when crosswind component makes the shimmering heat waves rise at about a forty-five degree angle. Some say this indicates a velocity of about two-mph. I don’t know what the actual velocity is, but if mirage continues to lean in the same direction, I know crosswind component is constant.

The third level of mirage is “Flutter.” This occurs when crosswind component reaches a speed at which mirage is lazily fluttering horizontally. If you can fire your record shots in this condition, with the close-in flags stable; you can shoot some terrific groups.

The fourth level of mirage is “Running” and the fifth, “Streaming.” Distinguishing the difference between these two is difficult, but with practice it can be done.

With flutter, run, and stream, mirage is flowing horizontally; the difference is in the frequency of the waves. Flutter has a very low frequency; run is noticeably faster, and stream is much faster, just before mirage washes out completely.

With the scope focused on the target, mirage reveals what is going on in approximately the last third of the range. You cannot rely entirely on mirage; you must also pay close attention to the flags in the first half of the range, but when mirage is visible, it is the best wind indicator for the back third.

Mirage blurs the target, making it more difficult and time consuming to establish point of aim, but in my opinion, based on experience and tests, it does not permanently displace the image, causing one to aim at the wrong spot; try the following experiment and I think you will agree.

Using a rail gun, carefully establish point of aim in the cool of the morning, and check it periodically throughout the day; you will see that it does not change. Yes, the target image will bounce around, but always snaps back to the same point.

I hope this clears up some misconceptions about mirage. Lean, flutter, run, and stream are my words; you may choose others, but these work for me. In reference to mirage, you will occasionally hear someone say, “Just because you can’t see it doesn’t mean it’s not there.” This person does not understand the difference between mirage and wind. Wind may be blowing and you can’t see it, but mirage is either visible or it’s not.

Many of you have read my articles in Precision Shooting about the Wind Probe, and how it always displays crosswind component in a single readout. Think about it for a moment and ask yourself, “Does mirage not do exactly the same thing?”