| || Effects of Launch Tube Curvature on Ballistics Accuracy
Author : Bundy, Mark L.
Source : Defence Science Journal ; Vol:47(4) ; 1997 ; pp 427-434
Subject : 623.4 Armaments and Ballistics;623.45 Ammunition
Keywords : Axial thermal expansion ;Ammunition dispersion
Abstract : It is possible for two different launch. platforms to produce centre of (shot) impacts (COIs), that differ in magnitude by several times the ammunition dispersion. It is difficult to discern what fraction of this variation is due to the launch tube alone, since changing tube alters both the mounting conditions and the occasion. A means has been devised to 'change tubes' without altering the mount or the occasion, by merely changing the shape of a given tube within the same mount. This is accomplished by localised control of a gun barrel's axial thermal expansion, implemented through a series of temperature-controlled heating pads adhered to the outer barrel wall. Using this technique, it was found that a simple, yet very common, bow-shaped curvature to the right verses left, for example, produced a significant shift in COI. Furthermore, it was found that holding the barrel shape constant dramatically reduced the standard deviation (dispersion) of shot Impacts about COI.