L-295 TNT Equivalence of Black Powder and its Gurney and Mott Constants
March 2023
Kevin M. Jaansalu (TSO – Materials Technology) This report captures information on the TNT equivalence and records the calculations that led to the Gurney velocity (√2E) and Mott constant (B). There is ample evidence that the TNT equivalence is less than one, depending on charge mass, confinement, scaled distance, means of initiation, and materials of construction. The largest experimentally determined value for TNT equivalence is 43% based on impulse. The Gurney velocity of black powder was found to be 816 m/s on the basis of the fastest fragment and 640 m/s for the 90 percentile of fragments. When in conditions of strong confinement, the value of the Mott constant is 3.6 g1⁄2 cm-5⁄6 ). The largest value of the Mott constant found from the data was 9.3 g1⁄2 cm-5⁄6.