Statistical Basis for Revision of a Ballistic Specification for Acceptance of Helmet Steel

摘要

When U.S. Army Tentative Specification AXS-1170 was originally set up comparatively few ballistic tests of non-magnetic steel of the thickness to be procured had been made. Moreover, the majority of these tests had been made with a soft lead (copper jacketed) cal. .45 bullet which at that time was considered an adequate criterion of service attack. Since that time the caliber .45 M1911 projectile has been modified by the replacement of the gilding metal jacket by copper clad steel and the addition of hardening alloys to the lead core, resulting in a projectile of greater resistance to deformation and, thus, greater penetrative power. Because of the decreased availability of the softer projectiles and in view of the fact that the harder projectiles represented a more realistic simulation of the types of missiles, helmets and body armor are expected to afford protection against, it was recommended that the harder bullets be used for acceptance testing of steel procured for helmets and body armor.