Human Effects Assessment of 40-mm Nonlethal Impact Munitions

An extensive human effects study was conducted on 40-mm nonlethal impact munitions having two different projectile nose configurations: a compliant sponge nose and a frangible foam nose carrying a powder payload. The study included an initial characterization of the rounds using the blunt criterion (BC). Injury risk assessment was done using two previously validated surrogates; thoracic blunt impact assessment utilized the 3-rib ballistic impact dummy (3RBID), and penetrating trauma assessment utilized a biomechanical surrogate consisting of ordnance gelatin and a specific combination of layers to simulate skin and underlying soft tissue. Production impact munitions were manufactured to produce a range of energy levels on impact by adjusting the propellant charge in the smokeless propulsion system, resulting in different projectile muzzle velocities. Twenty-three impacts were performed on the 3RBID biomechanical surrogate at kinetic energy levels in the range of 148–257 J to generate viscous criterion (VCmax) levels for injury assessment. The production configurations of the sponge and frangible-nose munitions were compared to the acceptable values for blunt trauma (VCmax ≤ 0.8). Thirty-nine impacts were done on a skin penetration surrogate at kinetic energy levels in the range of 170–305 J and the impact energies corresponding to penetrations were identified and compared with the production configurations for these munitions and with the expected energy density values for a 50% risk of penetration for specific areas of the body.