It can be shown that this is true, if the dynamic stability condition is fulfilled. If, on the contrary, a bullet is dynamically unstable, the angle of yaw increases. The occurrence of an initial yaw close to the muzzle is by no means an indicator of bullet instability. On the contrary, an initial yaw angle at the muzzle is inevitable and results from various perturbations. Bullets fired from handguns are not automatically dynamically stable.
Bullets can be dynamically unstable at the moment they leave the barrel.
Other bullets are dynamically stable close to the muzzle and loose dynamic stability as they continue to travel on, while the flowfield changes. According to our general definition of stability, a bullet may become unstable by being over-stabilized . Over-stabilization means that the bullet rotates too fast and becomes incapable to follow the bending trajectory, as its longitudinal axis tends to keep its direction in space. This effect is often observed for high-angle shooting, but is of minor interest in normal shooting situations. The figure schematically shows an over-stabilized bullet fired at a high angle of elevation, which lands base first.