Last weekend I shot the Western States Regional Long Range Championship (1000y F/open) and as an open shooter I got relay 1. Conditions were mild but not benign as far as wind, however first relay often had "mirage" causing image shift and produced vertical stringing on target for everyone. I dropped a couple points with very close 9's out the bottom because of it. Not a complete boil, but not enough wind to level things out.
How should image shift be handled to keep the group centered up and reduce vertical dispersion in aiming?
This is a pic of my target during those conditions (pasted shots are mine) and the gun and load is tuned in very well and currently hammering when enough wind shows up to flatten out the image shift. Score card from that days shooting.
How would you handle it?
View attachment 1709998View attachment 1710000
Don't know if I am understanding you correctly but
I will offer my technique
-----
When Mirage boils upward
Your image can only bottom out to most bottom it can go
which would be when no mirage is happening
Note this position of your reticle, if your reticle field of view extends out to the sides past your target
you can use a visual spot to line the horizontal of your reticle to the same spot elevation wise
also windage wise for that matter, say if your reticle lined up with a tree above the target, but mirage moves the target right due to wind, line your reticle up with the tree instead.
-----
In other words, you are firing from memory in a way comparing where the image always bottoms out to
If mirage happens, it doesnt matter, because you are aiming your reticle to where the image
"Should be"
by going from the spot it always bottoms out to
the image can only float upward (and sideways of course, but that's a whole different reading such as wind reading)
I am speaking only of elevation
---
Also keep in mind that wind, often comes in waves like the ocean
While the current may always be moving, the peaks often comes in waves like ocean peaks
Say 4 seconds in between
if you note the time of the peaks, you may be able to time when a gust comes and blows your mirage away for clarity, to verify where the image always bottoms out to to confirm your aiming point.
I like to time my shots at either full value for a known calculation
, or no value (a lull in between peaks)
---
In a way to take this a step further
Aim your rifle when no mirage happens - take your target away
Shoot at the spot where you remember your target being
---
In another aspect, this is also a pistol self defense technique, where you are aiming from muscle memory where you know your target is, but cannot see it
