Mirage: maybe a stupid question?

[P. Octo]

I was tuning a barrel yesterday in the range where the 1st WBRC tok place, in the South of France; temperatures went from 84°F to a bit over 93°F, relative humidity 51-55%. Even at 100m, through the X 45 Leupold, the mirage was pretty bad, just able to see the rings and the image bouncing around.
At first I concentrated hard to find a constant point where the dot would come back before shooting, then I had this thought:
First, that method meant that I was focused too much on the image and not enough on the wind flags then, second, I figure that the mirage is an optical illusion magnified by the power of the scope but that actually neither the target nor my rifle were dancing around; so what about putting the dot on a spot, let's say the bottom part of the bull and then forget the image and shoot the condition? And it worked!
Comments and criticisms are welcome.

 

[Boyd Allen]

I only pay attention to the mirage to see that it is relatively uniform from shot to shot. My flags are my primary source of information, and I use a 6 o'clock hold on the lowest position of the mothball, as it bounces. This is just a guess, but I would think that you would have to change what you pay the most attention to depending on local conditions, and experience at a particular range.

 

[Joe Krupa]

We get some gruesome mirage here at our Holton, MI range....

... as well as most places were there is little ground cover and/or sandy soil. Mirage can be a great indicator about what is happening down range; especially in conditions so light that the flags show virtually nothing happening. But, sometimes it can make seeing things on the target a bit of a challenge.

I love shooting in those conditions because it mentally screws up most of the competition who haven't been placed in that position before. I love to hear the comments flying around during the match ("where the bleep did that shot come from"). It goes without saying that these chaotic conditions fit well with my normal state of mind.

I wouldn't say that this is the best way to handle it, but it is what I have had to do when the point of aim is dancing all over the place. At Holton there is a clip on the frame holding the target in place. I put the verical reticle on the upwind side of that clip and attempt to center the horizontal crosshair between the white stripes on the mirage boards (so that the crosshairs are centered on what appears to be the record target).

Then when the flags kind of line up and the condition looks relatively stable, I blast five shots as fast as I can.... and pray from then on.

The definition of what is "stable" is a matter of experience and what you have been used to doing that is successful. I, personally, don't like to shoot in the "boil". It looks weak, but I have shot some monster trainwrecks in those conditions. And when the wind is blowing so hard that the difference betwen a 20 mph and a 30 mph isn't noticeable on the flags, you will notice that the view on the target looks like trying to see rocks on the bottom of a fast-moving stream. I hold off and wait for some reprieve.

But, a nice, weak, stable quartering wind will actually clear the mirage sight picture up and that is what looks good to me to shoot in.

On the activity of letting five fly fast during heavy mirage, my rationale is that if you can't see the lines on the target and/or the bullet holes, it is a prayer at best that you are going to hold off your last shot. I have lucked out some pretty decent groups in the L-T-F-F conditions (remarkably), along with some groups that predictably were gruesome. In those conditions you just have to take what the range gives you.

Just try and get something that you can reference on or near the target and let them fly. (I wouldn't want to try to sight in a rifle in those conditions.)