
Overturning moment coefficient derivative coefficient 

Yaw of repose vector 
The magnitude of the yaw of repose angle is typically only fractions of a degree close to the muzzle, but may take considerable values close to the summit especially for highelevation angles.
The occurrence of the yaw of repose is responsible for the side drift of spinstabilized projectiles even in the absence of wind. The spindependent side drift is also called derivation.
It can be shown that for righthand twist, the yaw of repose lies to the right of the trajectory. Thus the bullet nose rosettes with an average offset to the right, leading to a side drift to the right.
The above formula for the yaw of repose vector is an approximation for stable bullet flight.