Unlike firearm projectiles, air rifle pellets have evolved to a generally typical diabolo configuration. For reference, see: http://www.photosbykev.com/wordpress/2009/01/20/air-rifle-pellet-database/ The initial shape was described as like that of a badminton shuttlecock, and "skirt" at the bottom of the pellet acted as a stabilizing fin for projectiles of this type when fired from smooth, un-rifled barrels. Like firearms, modern air rifles have rifled barrels and use gyroscopic spin to stabilize the projectile in flight. The skirt's second function, being lighter and thinner than the head of the pellet, is to balloon, like Marilyn's skirt over a subway vent, expanding to seal the back side of the pellet, forming to the grooves and lands of the rifled barrel, while the narrower head rides the surface of the rifling. To a variable extent of depth and diameter, the underside of the skirt is hollow. The pellet exits the rifle in the axis of the bore with a uniform rate of spin (angular velocity) as well as forward velocity. Consider, as a generic model, a solid sphere with an attached, hollow truncated cone. The solid sphere, or head of the pellet, has a different angular momentum and rotational kinetic energy than the cylindrical (ring-like) skirt, but their initial angular velocity is identical. As the initial velocity and stored energy of the pellet decreases traveling down range, due to air resistance (both its linear and rotational kinetic energy), do the inertia of the rounded head and hollow skirt, both on a fixed axis, induce a rotational precession or wobble due to the linear differential of inertia from head to skirt of the pellet, independent of any other force acting on the pellet? Is gyroscopic stabilization of this type of pellet inherently unstable compared to a typical bullet shape due to differential in angular momentum of head and skirt? I hope I am asking clearly and in correct terms, as it's been a long time since I had any formal physics courses. If not, I hope you still understand the question. Thanks.