Page "Magnus effect" Paragraph 25

Overall, the effect of the Magnus force on a bullet's flight path itself is usually insignificant compared to other forces such as aerodynamic drag.

However, it greatly affects the bullet's stability, which in turn affects the amount of drag, how the bullet behaves upon impact, and many other factors.

The stability of the bullet is affected because the Magnus effect acts on the bullet's centre of pressure instead of its centre of gravity.

This means that it affects the yaw angle of the bullet: it tends to twist the bullet along its flight path, either towards the axis of flight ( decreasing the yaw thus stabilizing the bullet ) or away from the axis of flight ( increasing the yaw thus destabilizing the bullet ).

The critical factor is the location of the centre of pressure, which depends on the flowfield structure, which in turn depends mainly on the bullet's speed ( supersonic or subsonic ), but also the shape, air density and surface features.

If the centre of pressure is ahead of the centre of gravity, the effect is destabilizing ; if the centre of pressure is behind the centre of gravity, the effect is stabilizing.