
322 Ballistics: Theory and Design of Guns and Ammunition
This expression has some interesting implications. If we look back at the denition of our
parameter, M in Equation 9.66, we see that it is dependent upon the pitching moment
coefcient. This happens to always be negative for a n-stabilized projectile since the ns
impart a restoring moment. Unless there is some unique drag device, this moment is posi-
tive in a non-n-stabilized projectile. Because of this, a n-stabilized projectile is always
gyroscopically stable because P
2
must be positive. However, a non-n-stabilized projectile
must have a spin sufcient to make P
2
> 4M. We therefore ...