So, I've not learned much about mirage as I should've and without thinking through the potential issues of going to the range in the middle of the day in July to do some load development, I end up at the range with nasty mirage. I'm only shooting at 200 doing a bit of load development using Jerry Teo's method outlined in an article here at lrh, which has worked well for me in the past. Letting barrel cool pretty well between groups of two, just trying to find pressure and some hint of accuracy working up in .5g increments. At any rate, I've got mirage going up (it appears--range is grass and it's about 65F in the shade with 7-8 o'clock wind variable 2-5 mph or so) it appears, then mirage going sideways, it appears. And, i'm lucky to hold 3/4 MOA and this rifle should be capable of way less than that. I probably just should've packed up and gone home when I saw the mirage, I suppose. Did find pressure ceiling, so that was useful. Groups appeared to be 'clocking' a bit as Teo's article talks about--althought that is something to look for a little later in his process, but for the most part, the 2 shot groups were either pretty much verticle or horizontal, which makes me wonder if I was just seeing hor./vert. mirage issues. If so, I didn't realize how much effect the mirage would have at 200 yds. Make any sense to anybody?