Propellant Residues Deposition from Firing of 40-mm Grenades

Abstract : Military live-fire training utilizes energetic materials that are never completely consumed. In February 2010, tests were conducted at Fort Richardson, Alaska, to determine the propellant residues deposition rates related to the firing of 40-mm grenades from an Mk19 machine gun. Two test pads were constructed, with 127 Mk281 (BA12) training rounds containing F15080 propellant (9.1% nitroglycerin-NG) fired over one and 144 M430 (B542) high-explosive rounds containing M2 propellant (19.5% NG) fired over the other. Replicate multi-increment samples were collected from the snow surface downrange of the firing positions in three sampling units on each pad. Samples were analyzed and results composited to derive an estimate of the unreacted energetics mass. The total estimated per-round deposition rate for the M430 high-explosive cartridge is 76 mg/round, 8.4% of the original NG load. The deposition rate for the Mk281 cartridge is 2.2 mg/round, 0.59% of the original NG load. Energet-ics deposition rates for the M430 rounds were between those for mortar projectiles and shoulder-fired rockets, which also utilize double-based propellants, are medium-velocity projectiles, and are fired from short-barreled guns. The Mk281 cartridges, with their NG-impregnated propellant grains, had a much lower NG deposition rate but a greater mass of unconsumed propellant.