Wind deflection is by a wide lead the most challenging topic in marksmanship, both to navigate conceptually and to accurately account for in field. While most variables in a ballistic solution can be corrected for with certainty and consistency, by nature wind is a dynamic force, making this topic the least predictable aspect of any long range shot.
Accurate accounting of wind deflection requires not only an understanding of wind direction and speed at the firing position, but also an understanding of wind behavior at the target location and everywhere in between. Accounting for the effects of wind on our bullets trajectory is where science meets art - even ballistic computers fall very short of reliable when considering the full spectrum of wind variables on the path from rifle to target. Fortunately, UNITAF's environmental settings do not reproduce all variables present in real life wind, permitting the topic to be accessible and more predictable for the highest levels of marksmanship.
Variables
Direction and speed are the primary two variables to consider when factoring for wind. Although wind speed affects a bullet in a straightforward fashion (faster wind produces more deflection), wind direction has more complicated effects on the path of a bullet:
A wind from the left pushes the bullet to the right.
A wind from the right pushes the bullet to the left.
A wind from directly behind (tailwind) raises point of impact.
A wind from directly ahead (headwind) lowers point of impact.
These principles can be combined if the wind comes at a quartering angle; meaning a wind that blows from both behind and to the left can shift point of impact higher and to the right simultaneously.
The direction of wind will also influence how much of a winds “pushing power” is used to push a bullet left or right, and how much is used to raise or lower point of impact. For example;
A 4mps wind from 3 o'clock may deflect a bullet 2 mils to the left.
A 4mps wind from 4 o'clock may only deflect a bullet 1 mil to the right, but will also raise point of impact.
As a dynamic force
The variables of direction and speed are the only practical aspects of wind that can deflect a bullet at any given time. Accounting for these variables holistically is exceedingly difficult, however, as:
Wind speed may change at distance when obstructions are present.
Both wind speed and direction may change sporadically.
The most thorough and accurate wind solutions will include:
- Measuring and accounting for wind at the firing position
- Accounting for wind obstructions at all points in a flight path.
Relevance
Wind makes itself a relevant factor in all applications of marksmanship, the force having a much greater effect on a bullets trajectory than intuition would hold. Even wind speeds not yet fast enough to be felt on our faces can produce a point of impact shift large enough to produce an outright miss at distance. Especially when placed in the context of human targets, which are much less forgiving horizontally than they are vertically, wind must be accounted for by all - from SF Sniper teams engaging an HVT to riflemen on a conventional battlefield. The level of care that must be applied to account for all variables present in wind deflection, however, depends heavily on the application of marksmanship.
Although wind must be accounted for by anyone firing a rifle, the level of detail required when compensating varies by role.
