The most important objectives of ballistic investigation at the present time are those concerned with uniformity. It is of greater practical interest, for example, to learn how to cause the gun, as a heat engine, to execute its cycle uniformly from round to round than it is to increase, or even to maintain, a particular thermodynamic efficiency. Statistical evidence indicates that such development is a primary requisite, in many cases, for marked improvement in the precision of gunnery, however good projectile design and nominal exterior ballistic performance may be. This refers to normally accurate conditioning with respect to fire control and does not mean, of course, that moderate or large-range deviations always originate in variations other than those of flight characteristics. It is rather that deviations from exterior uniformity of the latter nature are usually the direct result of some abnormality developing initially within the gun.
Ballistic Engineering Problems: Empirical Summaries
By L. Thompson, Physicist, Naval Proving Ground, Dahlgren, Va.