Timely topic for me; I was feeling pretty good yesterday - I had been pounding my gongs (620, 760, 910) all week and had put every bullet within 5" of center. Yesterday I shot at my 910 in the morning with my .338 Edge- figured 1 mph to left and hit just above the 3" aiming square. Went for a bike ride; wind came up big time. Took out my .338 Savage Lapua and shot at 760. Figured 3 MOA wind hold and nearly hit the 3" square - was feeling unbeatable. (I had made the same shot the day before with my Edge, same 3 MOA hold.) Then the wind really kicked in - gusting big time, switching directions all over the place. Decided to take a shot at 620, which I hit just about every time in strong winds (10"x12"). Missed just right. Waited an hour. Missed just left. Waited two hours and decided to see if I could hit at 500. Wind was left to right, but I checked my parallax focus at the last second and was stunned to see it was right to left; a quick glance at my wind flag at my shooting site confirmed that. Missed just left. Worst day of shooting in a long time.
I have now spent three years shooting LR pretty much every day at my CO place; this experience is unbeatable - I shoot in some pretty challenging situations that I would never do in Arizona, simply because I have to drive to the desert, and I generally don't do that in really crappy conditions. Here is what I have learned (not all in the last three years):
- Winds head on or from behind are extremely tricky - 11 o'clock is 1/2 value hold to the left while a 1 o'clock is 1/2 value the other way. A wind from 8 o'clock is 91% full value, but so is one from 10 - so you only deal with 91-100% full value. Wind speed is the key here, while direction is the focus for head on or tailing winds.
- If your Kestrel is showing wind changing +/- 5 mph within 2 seconds you are not going to hit an animal's vitals at 600 yards, let alone 800.
- Most mornings here are dead calm but at 1000 yards even a slight wind you cannot detect can play havoc. First light offers no mirage, and a 1-2 mph wind is not going to blow vegetation - at least not pine trees.
- If I can see mirage, my hit rate is off the charts. If I can't, my wind flag/vegetation is my only option - I cannot consistently hit within 5" at 910 if there is a reasonable wind but no mirage.
- Shooting at the same place every day allows you to learn the nuances of that location. If I were running a shooting school here, I could look like a genius; I know the prevailing wind in the summer at first light is from the left. The attached video is a shot I took at my 1047 yard rock this morning. Kestrel showed zero wind. My wind flag was dead. However, a lighter flame bent slight to the right. Because that rock is so much higher, I figured I would hold 1 MOA left instead of 1/2, which would be zero wind (I zero spin at 500). The video was made by recording a playback on my iPhone, so it is blurry, but you can see I hit just below and to the right of the aiming square, which is 2x2." But the reason I am posting the video is because you can clearly see the dust from the rock drifting to the right.