The MEI Hellhound 40 mm low-velocity multi-purpose grenade is a fixed-type munition designed to be fired from a 40×46mm grenade launcher such as the M79, M203, M320 (attached to the M16 series of rifles or M4 carbine), or Milkor MK-1.[1][2] The round consists of a metal projectile body, a fuze, and a cartridge case assembly. Upon impact with the target, the firing pin is driven into the detonator, which in turn sets off the round, producing a jet which sets off the explosive from the base forward. This results in an armor-piercing jet of molten metal and fragmentation of the projectile body.[3] The MEI Hellhound uses the same high-low propulsion system as other 40 mm grenade launchers.[4]