Shooting In Wind
The wind’s effect on a bullet’s flight has been a subject of heated discourse for as long as shooters have been trying to hit targets at long distances. We have developed charts and computer programs in attempts to make predictions, but at best, they are only a guideline. All the mathematical theorists from Einstein to my cousin Philip can’t predict exactly what a bullet will do when it is fired through a real-world moving air mass.
However, the computer programs and ballistic tables are useful in teaching you the wind’s effects, and it is hardly a waste of time to study them. For example, the accompanying table will give you some idea of the difference of wind direction on a bullet’s path. It will also help to illustrate the degree of wind deflection on differing bullets and velocities. But the flaw in these tables and programs is that the predictions are built on laboratory conditions and assume a constant force and direction of wind.
Looking at Real-World Variables
Things are different in the atmosphere we shoot through. Winds gust and wane with currents and flows affected by terrain, vegetation and a million other factors. While it may be blowing one speed where you are, your bullet can travel through wind that is moving several different speeds before it reaches a distant target. The same goes with wind direction-over a given distance it can curl around, double back, eddy, switch and change its attitude more times than a six-year-old with a sugar buzz. If there is one constant in a wind’s influence on a bullet, it is the inconsistency.
The effect, as predicted in the charts and computer programs, is based on the velocity and ballistic coefficient of the bullet, which determines the time of flight, or the amount of time the wind has to act on the bullet. The more time in flight, the more the wind will blow it off course. Other factors include the bullet’s size and shape, which dictate the amount of area available for the wind to blow against. The bullet’s weight is also important because it is easier to push around a light object than it is a heavy one. Whom would you rather wrestle, Hulk Hogan or Bill Gates? Same principle.
Wind direction is yet another factor. A 90-degree side wind will blow against the full profile of the bullet, but any angle that is different will be acting on a differing percentage of the bullet’s surface. A full head or tail wind will have either the point or the base of the bullet to blow against, which affects retained velocity and, consequently, bullet drop. For example, a .44 Rem. Mag. 240-grain bullet with a 20 mph tailwind will have almost 100 fps more retained velocity at 500 yards than the same bullet with a 20 mph headwind. This will change the bullet path even though there is no theoretical wind drift and the difference in drop is almost 45 inches. Of course, this is an extreme example, and nobody really considers the .44 Rem. Mag. a 500-yard cartridge, but every bullet from any cartridge will be affected in some way.
Now suppose the wind is gusting from a 45-degree angle, or 20 degrees or perhaps 10 degrees. Maybe it will be from all three before the bullet makes it from your gun to the target. How much will that affect the lateral wind drift? How about the bullet drop?
I don’t have a clue.
Neither does anybody else, not with all the variables.
Consider Your Bullet, Too
A bullet’s energy would seem to play a role as well, and the more energy it has, the better able it is to counteract the effect of the wind. This was illustrated to me while I was hunting prairie dogs in South Dakota with Dave Brown, the marketing director for Pentax Sport Optics.
The prairie dogs were getting spooky, and our average shooting distance was growing at about the same time the wind started to really pick up. The bullets from our .223 Remingtons were being blown 30 inches or more at 400 yards. The gusting winds made predicting the shots tough, and the points of impact were very erratic. Dave broke out his custom .243 Ackley Improved, and with its heavier 80-grain bullets, the effect of the wind was not only much less pronounced, but a lot more consistent and easier to predict. I was spotting for him, and I was amazed at the difference in the amount of wind deflection and in the consistency of that deflection between the .243’s 80-grain bullets and the 50-grain bullets we had been using in the .223 Rem.
The computer didn’t predict it, and if I hadn’t seen it myself, I would not have believed it. A lot of prairie dogs who also weren’t true believers learned the same lesson that day.
An Art In Itself
Shooting in the wind is far more of an art than a science, and the only real way to learn about reading the wind is to get out and shoot in it. A couple of days in a prairie dog town will teach you more than all the theoretical computer programs or printed ballistic tables in the world. If there is a pronounced lack of prairie dogs where you are, simply find a windy place with some good distance and shoot at rocks, clay pigeons, plastic soda bottles full of water or even paper targets, and do it with a variety of firearms. Have a pal watch your hits through a spotting scope and try to evaluate each shot. After a few thousand rounds or so, you may finally start to get a handle on reading wind.