Wind Drift
Definition
Lateral deflection of a bullet by a crosswind component. Grows with time-of-flight (faster than range) and is the most variable error source in long-range shooting reconstruction.
- Cause
- Crosswind component acting on the bullet
- Growth pattern
- Increases faster than range with time of flight
- Reconstruction role
- Most variable error source at long range
Common questions
Why does wind drift grow faster than range rather than in direct proportion to it?+
As the bullet loses velocity downrange it spends more time exposed to the crosswind per unit of distance travelled, so the lateral push accumulates disproportionately over the later part of the trajectory compared with the early, faster portion.
Why is wind drift singled out as the most variable error source in reconstruction?+
Unlike bullet drop, which follows a predictable gravity curve for a known load, crosswind speed and direction can change during the time of flight and are rarely measured precisely at the moment of the shot, making the correction an estimate rather than a fixed calculation.
Related terms
- Aerodynamic Drag
- The retarding force exerted by air on a moving projectile. Proportional to air density, the square of velocity, the drag coefficient, and...
- Ballistic Coefficient (BC)
- The ratio of a projectile's sectional density to its drag relative to a reference standard (G1 or G7). Higher BC means less...
- Drag Coefficient (C_D)
- A dimensionless number characterising the aerodynamic drag force relative to the dynamic pressure and the projectile's cross-sectional area. Varies with Mach number;...
- G1 Drag Standard
- The Gavre Commission reference projectile: flat base, round-nose ogive. Established in the late 19th century and codified at Aberdeen Proving Ground. Standard...
- G7 Drag Standard
- A long, boat-tailed secant-ogive reference projectile developed by Bryan Litz at Applied Ballistics. More accurate for modern spitzer-BT precision and military rifle...
- Hatcher Rule
- A simplified wind-drift estimation formula from Major General Julian Hatcher's Hatcher's Notebook (1947). Useful as a field check and courtroom cross-reference; diverges...
- Litz Wind Drift Model
- The velocity-integrated wind-drift calculation method from Brian Litz's Applied Ballistics for Long Range Shooting (2015), implemented in AB Quantum and Hornady 4DOF....
- Sectional Density
- A bullet's mass divided by the square of its diameter (in consistent units). A component of BC; higher sectional density generally produces...
- Transonic Regime
- The velocity range from approximately Mach 0.8 to 1.2 (272 to 408 m/s at sea level, 15 degrees C). Wave drag peaks...