Advanced Marksmanship Questions about mirage

[Cme]

Heya guys, I'm a new member hoping to tap your expertise.

I'm a starting (long range) shooter and I have read what I could find about mirage, but not yet experienced it.

From what I have read so far there are two main reasons for mirage reading:
1 - Estimate the (cross) wind speed and angle [left to right, or right to left] at the target and at different distances across the range.
2- Knowing how a mirage distorts your target picture and be able to adjust for that.

I have seen two different graphic representations of mirage and I am unsure which one is correct.

http://www.gun-club.net/wiki/lib/exe/fetch.php?cache=&media=image4838.gif
Here at all windspeeds, from 2 to 10 mph, the <span style="font-style: italic">wavy lines</span> are all horizontal, but decrease in amplitude.

<span style="font-weight: bold">OR</span>

http://www.bkmorrow.com/WestCoastTactica...-Icon_small.jpg
Here the angle of the mirage changes with the windspeed.

Which of these graphic representations best resemble the mirage effect?

And a second question.
How does a mirage effect the target picture and how would you adjust for that?


PS. Please correct my technical jargon, I'm just starting out.

 

[Redmanss]

Re: Questions about mirage

The second link was a tiny picture. The first one seems a bit too basic.

The only way to really learn mirage reading techniques is to get out there and call it. Reading it for wind speed, depending on how fast it is blowing that day, can be difficult. After it lays flat, good luck trying to get a scientific read off of it.

Spot using everything at your disposal. Trees and other plants, dust, flags, wind meters, whatever. It's more of an art than a science, and it only comes with experience. This is why it is such an advantage shooting on your home range vs. a visitor. They know what to look for and how it acts. Find a local to help get you started (fill out your profile and someone might roger up).

Use your shot calls/impacts as the true judge as the bullet never lies, and learn your environment that way. Use a data book to draw how it appears to you with notes for future reference. Reverse judge your wind call using wind drift charts from JBM or other similar ballistic program.

As for appearance of mirage and the effect on the target image in the scope, if it is too bad dial down on your magnification.

Welcome and happy shooting.

 

[customshooter]

Re: Questions about mirage

Another technique I have used is setting up a scope under high magnification during a heavy mirage day. Rigid mount the scope (on a stand or your gun) and aim at the target. Do this in the morning. Throughout the course of the day look through and see where the image has shifted relative to where you placed your crosshairs during set-up. This will give you a shift in aim necessary for the mirage. A similar technique is used by the AMU...

 

[rwest309]

Re: Questions about mirage

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: customshooter</div><div class="ubbcode-body">Another technique I have used is setting up a scope under high magnification during a heavy mirage day. Rigid mount the scope (on a stand or your gun) and aim at the target. Do this in the morning. Throughout the course of the day look through and see where the image has shifted relative to where you placed your crosshairs during set-up. This will give you a shift in aim necessary for the mirage. A similar technique is used by the AMU... </div></div>

That is a hell of a tip right there.

 

[Garvey]

Re: Questions about mirage

"2- Knowing how a mirage distorts your target picture and be able to adjust for that."

Have you seen a target with a heavy mirage? Quality glass will help but it will not make the mirage occlusion of the target go away. It's kind of like being drunk and seeing double. You have to aim for the one in the middle. It will make your target appear as if it is actually doing the moving. You have to look for the happy medium. Meaning how far does it seem to be moving up and down, left and right, and average that. At least that's how I do it.

And yes the tip of setting up a scope on a target in the morning and looking at it through out the day is definately good training without firing a shot.

 

[Sterling Shooter]

Re: Questions about mirage

Mirage does not need to distort your sight picture, since the primary mirage reading tool is the spotting scope, not the rifle's scope. And, typically, the spotting scope will be focused on the target, then, re-focused on mid-range mirage by turning the focus knob counter clockwise 1/4 turn. At that setting, the shooter can see mirage, as well as a slightly out of focus target. Factoring mid-range wind is proven effective for correctly countering for wind effects.

Reading mirage, when that's possible, also helps the shooter to discern prevailing wind; and, with the spotting scope used to check for prevailing wind between shots, a better outcome is assured.

In addition, reading wind from mirage, as opposed to reading wind by appraising wind effects, like from observing smoke, precludes the need to factor for wind value, since velocity is valued by the scope's direction.