UNCERTAINTY: WHAT DOES IT MEAN FOR BALLISTIC CHRONOGRAPHS?

Abstract

Two of the most cited performance properties of ballistic armour systems that characterize resistance to penetration are the ballistic limit (V50) and the proof velocity (Vproof). It is therefore critical that the test velocities are measured with a high degree of certainty for gaining confidence in the ballistic performance assessment for research and development, demonstration of compliance, and quality control purposes (i.e., ISO 17025). Unfortunately, common ballistic testing standards (NIJ 0101.06, ASTM E3062, etc.) do not provide sufficient clarity regarding contributors to consider, coverage factors, or interpretation of stated accuracy limits, leaving significant room for interpretation. This work applies principles of the Guide to the expression of uncertainty in measurement (GUM) to a COTS ballistic chronograph (SpeedTubeâ„¢) to form a basis for discussions regarding interpretation of standards and the need for standards to use language consistent with the International Vocabulary of Metrology (VIM) for the benefit of researchers, manufacturers, and test facilities.