Magnus Effect
Definition
A force on a spinning body in a crosswind perpendicular to both the spin axis and the crosswind direction. Produces a vertical force component on a spinning bullet in a crosswind: upward for a right-twist bullet in a left-to-right wind.
- Cause
- A spinning body moving through a crosswind
- Force direction
- Perpendicular to spin axis and crosswind
- Applies to
- Spinning projectiles such as bullets
- Practical relevance
- Long-range ballistic trajectory corrections
Common questions
How does the Magnus effect differ from spin drift in long-range shooting?+
Spin drift is a lateral deflection from the bullet's gyroscopic response to gravity acting on its nose over the trajectory, while the Magnus effect is a separate force generated specifically by a crosswind acting on the spinning bullet.
Why does a right-twist bullet experience an upward Magnus force in a left-to-right wind?+
The spin combined with the crosswind creates a pressure difference across the bullet's surface, similar to lift on a spinning ball, and the direction of that force depends on the combination of spin direction and wind direction.
Related terms
- 4DOF Model
- A four-degree-of-freedom ballistic model that adds aerodynamic pitch and yaw to the standard 2DOF (gravity + drag) model, accounting for spin drift...
- BDC (Bullet Drop Compensator)
- Elevation turret or reticle markings that encode the required elevation correction for a specific load at preset ranges. Allows rapid correction without...
- Coriolis Effect
- Apparent deflection of a moving body due to the rotation of the Earth. In the Northern Hemisphere, deflects projectiles to the right...
- Eötvös Effect
- The vertical component of the Coriolis effect on a bullet. Increases impact elevation for eastward-fired shots, decreases it for westward-fired shots. Typically...
- Fire Control System (FCS)
- An integrated optic, rangefinder, and ballistic solver that computes and displays a real-time firing solution. Examples: TrackingPoint PGF, Elbit FALCON, Rafael MARS....
- Laser Rangefinder (LRF)
- A device that measures range by timing the return of a laser pulse from the target. Typical accuracy: plus or minus 1...
- Miliradian (Mil)
- 1/1000 of a radian. Equal to 10 cm at 100 m, 1 m at 1,000 m. Used as the angular unit in...
- MOA (Minute of Angle)
- 1/60 of a degree of arc. Equal to approximately 2.908 cm (1.047 inches) at 100 m. Used in civilian and some law...
- Spin Drift
- Consistent lateral drift of a bullet in the direction of rifling twist, caused by gyroscopic precession of the bullet's nose around the...