Mirage Effect

How much effect can mirage have on someone who has no idea how to deal with and/or adjust for it? I'm talking about me if you didn't get that?

I'm not sure what to make of my results from shooting yesterday. the first is my 100 yard starter target. The second are at 300 yards. So if you count from left to right on the bottom row of the 100yd target, then positions 1, 3 and 4 are the as order seen on the 300yd target ascending in powder charge.

I was just shooting groups and couldn't see results in between.





By the last set at 300yds, a storm was rolling in instantly felt cooler and the had a hard over past to where I didn't see a mirage at all.

Thoughts are welcome, especially on what to do when mirages happen. I do live in Texas after all.

Don't know if it matters but...
Home built 6.5 grendel with a Odin Work 1:8 barrel 18"
123gr eld
28.3 to 28.9 grains of RL-15
CCI small rifle magnum (don't remember the number)

In a boil I've seen over a minute of poi shift.

Mirage is the refraction of light by heated air. It will play havoc on group shooting or keeping a constant POI. And when the wind blows and the mirage bends right or left, it will turn your POI also. In the summer time, I get to the range at sun up to do my shooting and be done by 10:30 or 11 to avoid the mirage. In Texas, this is how I combat it. The other way is to dial your scope magnification way down. You can not shoot through mirage on high power and get any kind of consistency.

To combat it even more, you can shoot over water. There will be no mirage over water. Another way is to get higher off the ground. This is why shooting from an elevated tower or position helps with mirage. The easiest way to deal with mirage though, is to simply dial down your magnification on your scope. Shooters that have the high power 8-32 scopes and try to shoot on high power in the heat is impossible.

When mirage is bad, turn the magnification down, thus the reason for first focal plane scopes. Lately, it has effected me at 100 yards. I had a dancing point of aim at 25X, so I turned down to 18X to zero a scope.

Shooting long ranges it is often your friend. It tells you two things 1. Which direction the wind is blowing 2. How hard it is blowing, up to 10mph. With my customers, I explain it, draw pictures of it, then we talk about it all day long, on every shot. I will tell them what I am looking at, and that I turned down my focus for a far shot, so that I can read mirage. In the winter, there is often a tail wind on my range. And it will rarely be 6 o'clock to the shot. It will be 5 to 7 o'clock. So as wind angle changes, the mirage will tell you so, if you know what to look for. You will see it leaning 10° right, that tells you a 7 o'clock wind, so hold left. Then when it switches, you'll have a momentary boil, showing a 6 o'clock wind, so no wind hold. Then it will lean 10° left, showing you a 5 o'clock wind, so hold right. It is something that takes lots of practice to get good at reading. After 50,000+ rounds, I am still practicing.

There is mirage over water...

I thought it was as si.ple as just focusing on the target and waiting for the moment it looked like it wasn't bouncing around anymore.

I mean I know it's not alinea thing but I was surprised how much variation there was at 300 between loads when it seemed much closer at 100. Of course it's shooter error and not the loading.