Mirage - how to adjust for it?

[tlk]

OK, so I tried to shoot this afternoon in some high heat (97 F) and ran into a boiling mirage. Holy crap! My aiming point was a dot about .3" on the target - half the time it was GONE or DANCING and blurry. I was shooting prone.

My groups were decent but I still missed to the low side. How do you correct for this?

 

[jmason]

Try cutting back on you magnification if you can.

 

[tlk]

Can't, my scope is a fixed 10x.

 

[jmason]

Well I'm at a loss. Maybe one of the fixed power guys will chime in. The way it looks though, you may be able to mess w/ your focus. A little blur is probably better than a dancing target.

 

[royinidaho]

tlk,

If mirage was raging at 10X it was really raging.

Here's something to do. Make your POI dot at least 0.5" to be more visible more of the time.

On a heavy mirage day, set the rifle in a solid set up so that the reticle is perfectly centered on the dot, with no human intervention (don't touch the rifle in any way.

The sneak up on the scope and watch the dot do the dance thing.

Mirage will be either drifting left or right or boiling straight up. The word on the street is to never shot when its boiling.

Watch it over a period of time and you may see that one conditions occurs more than others. This is the condition that you want to shoot under.

The next experiment would be to set up the target and shoot a shot or two just after day light. Then a shot or two at the same target every 30 minutes until about 10 AM. If it's a heavy mirage day your results will be interesting.

THe long and short of it is that once you learn how to read mirage, it will be come your friend instead of your enemy.

I think Boss Hoss is the one that says that from time to time.

 

[Burt surveyor]

Watch it over a period of time and you may see that one conditions occurs more than others. This is the condition that you want to shoot under.

My survey theodolite has a 30x scope, and mirage is a problem for me, too.

I try to take long shots at low-mirage times, but when I can't avoid it, the above is good advice. Mirage is usually variable.

We call our technique "meaning it out", or picking the repeatable sight point. Watch the crosshairs come back to a point when the dancing is lower, and then average that out.