Windage by the Book 13NOV2008

On my last outing the wind blowing 10-15mph (5-7m/s) and gusting to over 20mph (9-10m/s) was intimidating. It put a bit of an edge on the range session and it shook my confidence. I had forgotten the advice an experienced long range shooter had once given me, “The wind is your friend; get to know it and it will treat you right.” I was estimating windage in a touchy-feely manner, dialing some in and then using changes in target hold to compensate for the rest that was needed to make hits. I was using instinct and experience to put the shots on metal. I didn’t want to lose the “bubble” (not know where I was in my applied windage corrections) and start chasing my shots around, especially without someone on the spotting scope to help me see where I was going wrong. What I mean by this is, being alone with no spotter to help me see how I was missing I wanted to set my self up to miss for cause of the wind, then it was a matter of just moving my hold-off a bit into the wind to bring the shot on. Though it worked, in reviewing this range session, I could have done a couple of things to improve my results and give me more confidence in the windy conditions.

First, when the wind wasn’t gusting it was fairly steady. So I should have just taken the difference between the steady wind and the gusts, halved that difference, and added it to the steady wind value to come up with my final wind value adjustment. That would be the difference of 12mph and 20mph which is 8mph and halved is 4mph added to the steady value of 12mph is 16mph or 7m/s.

Next, I should have referred to my copy of the 1942 Soviet PU Sniper’s Handbook’s windage chart. According to the Handbook, aim point shift for a 90 degree 7m/s wind for 400m is about 60cm. On the PU scope’s windage adjust knob scale that would be 1.5 mils in the “+” or right direction to shift the aim point right to counter the right to left full value wind. Each mil mark on the windage scale is 10cm at 100m. One mil at 400m is therefore 40cm, and another ½ mil at 400m is an additional 20cm for a total adjustment of 60cm right shift. For my 400m shots, I had dialed in a ½ mil right windage or 20cm and was using hold off right by another estimated 12 inches (6 inches from target center to right edge plus another estimated half a target's width right) or 30cm for a total of 50cm. So my actual hold off was fairly close to the Handbook’s recommended aim point shift. The point is, eventhough this post-session wind estimation and Handbook data hold-off may not have been perfect, it would have been close enough for me to adjust and take a hold on the target to make hits rather than having to take a hold on a harder to repeat imaginary spot somewhere off the target like I was doing.

Instinct and feel for what corrections should be made to make the shot is a good thing to have. Applying this experience from a solid base of reasoning and ballistic data has got to be even better. Next time I am not going to be daunted by the wind. I am going to come to terms with it by putting a number value on it and using all my knowledge assets to adjust and make that first shot hit.

Safe shooting, John




Ballistic Table for 400m conditions on 03NOV2008 calculated with Handloads.com online ballistic calculator (see link at side bar) :