Shooting in Mirage

[KQguy]

The last few times I have shot in heavy mirage,I noticed I end up about 2moa low at around 900-1000yds.,Is this normal.Is there anyway to predict what the effects of mirage will do at certain distances?I am assuming the mirage is just making the target appear in a different spot than where it actually is.I find mirage to be the trickiest condition to shoot in.Are the effects of mirage alway's the same?

 

[royinidaho]

Shooting in mirage is pretty much like being married to the wrong woman!

Rule 1: Don't shoot when its boiling! (no wind). But what if it's consistently/constantly boiling?

A personal experience from my years ago benchrest testing....
From pre sunrise until 1030 one shot every 1/2 hour after the first shot.
POI increased a total of 2 1/2" @ 100 yards.

Range was newly built with bare dirt and test was conducted last week of July, the hottest time of the year in SE Idaho.

The sad thing about it is that in all of those years it hasn't gotten any more forgiving!

FWIW

 

[KQguy]

Shooting in mirage is pretty much like being married to the wrong woman!

Rule 1: Don't shoot when its boiling! (no wind). But what if it's consistently/constantly boiling?

A personal experience from my years ago benchrest testing....
From pre sunrise until 1030 one shot every 1/2 hour after the first shot.
POI increased a total of 2 1/2" @ 100 yards.

Range was newly built with bare dirt and test was conducted last week of July, the hottest time of the year in SE Idaho.

The sad thing about it is that in all of those years it hasn't gotten any more forgiving!

FWIW

Are you saying that your point of impact actually moved up,as the mirage got worse?

 

[Michael Eichele]

A couple of things that affect the perception of where your target is in mirage is wind and lighting. Mirage or no mirage, various lighting conditions will make your perception of the target different. Add mirage to the mix and it only compounds itself. Wind will make it worse. Shooting a target that is very near the ground or when your target is near the ground via your line of sight even if the target is 6 feet off the ground adds even more to the mix.

2 MOA at 1K (about 20") seems a bit extreeme. I would say if you are 20" low at 1K that there could be something else at play. Double check everything else. I could certainly be wrong, but 2 MOA seems like a bit much.

 

[MontanaRifleman]

Are you saying that your point of impact actually moved up,as the mirage got worse?

No, he's saying don't marry the wrong woman

 

[uncleB]

Shooting in mirage is pretty much like being married to the wrong woman!

I agree except for the fact that mirage does not take away your house and guns like the wrong woman WILL !!!!!!!!!!!!
UB

 

[royinidaho]

Are you saying that your point of impact actually moved up,as the mirage got worse?

I said what I said and I'm sticking to it.....

Target was ~3' above ground. Shooting bench was standard height.

Dirt was just dozed to remove a much top soil as possible for safety berms. Lava rock showing in a lot of places.

When I attempt to dope mirage I do ok when looking through scope but when talking about it I usually get things exactly back wards.

If mirage is to the right then the bull appears to the right so ya hold left to compensate. The other way for when left.

When its boiling, no wind, and mirage increasing as the difference between sun intensity/air temp and ground temperature increases (or whatever the process is) the bull dances like a ball on a rubber band with the ball continually appear to change size as if its pulsating to the extent that @ 26X there is no hope of focus.

I wonder if its really effective to reduce scope power so that mirage can't be seen? Its still there?


Also I pay more attention to mirage than wind. Though they are very closely related.

 

[Autorotate]

Shooting in mirage is pretty much like being married to the wrong woman!

We need to start the Ten Commandments to Long Range Hunting.....I nominate this to be Commandment #1.

 

[Bravo 4]

I agree except for the fact that mirage does not take away your house and guns like the wrong woman WILL !!!!!!!!!!!!
UB

Now you are comparing the wrong woman to a tornado.

 

[Bravo 4]

I agree with Michael that 2moa is quite a bit but if given like conditions (temp, BP, etc) and consistant results you have an understanding of what heavy mirage can do to your perception of the target and point of aim. Mirage is kinda like the wind in the fact that it changes throughout the day and a light mirage will not effect you like a heavy will. You seem to be doing the right thing and keeping good notes about it's effects. I prefer at least a little to help with wind speed and direction.

 

[shortpants]

I know this is an old thread but I thought I'd share an experience I had this last weekend that I feel shows how drastic your POI shifts can be due to mirage.
My friend and I were shooting 2 different rifles ( both 300win mags ) and both shooting the same handloads. We both zeroed our rifles and then began shooting a seating depth test. The mirage was so bad that as we adjusted our parallax our targets never seemed in focus so we did the best we could. We were shooting at 250 yds. After making sure our zeros were both perfect we each shot a group. Both of us impacted 12" low!!! We were both dumbfounded since it was both rifles. We then each shot our next group except he made no adjustment to his turret and I adjusted mine to compensate for the last group. His group fell right back on the bullseye while mine sailed high and over the target! Our only explanation is mirage. We are in Arizona and the temps out in the desert were in the mid 90's. It was very hard to figure out were the dancing bullseye was.

 

[RMulhern]

Go out some early morning, put your rifle in a cradle protected from the sun and put the cross-wires on a target from 600 yards or back further and go back from time to time and take a look!

 

[dig]

Thanks Roy, I have had similar result here in the desert but have not done enough thorough testing to verify. Reading you post I believe you are spot on. Conforms to my theory.

 

[elkaholic]

I know this is an old thread but I thought I'd share an experience I had this last weekend that I feel shows how drastic your POI shifts can be due to mirage.
My friend and I were shooting 2 different rifles ( both 300win mags ) and both shooting the same handloads. We both zeroed our rifles and then began shooting a seating depth test. The mirage was so bad that as we adjusted our parallax our targets never seemed in focus so we did the best we could. We were shooting at 250 yds. After making sure our zeros were both perfect we each shot a group. Both of us impacted 12" low!!! We were both dumbfounded since it was both rifles. We then each shot our next group except he made no adjustment to his turret and I adjusted mine to compensate for the last group. His group fell right back on the bullseye while mine sailed high and over the target! Our only explanation is mirage. We are in Arizona and the temps out in the desert were in the mid 90's. It was very hard to figure out were the dancing bullseye was.

That is a very good and descriptive analogy......Rich