Militech M-31a1 Advanced Infantry Combat Weapon

Militech M-31a1 Advanced Infantry Combat Weapon is assault rifles. Two years ago, the Provisional United States government proposed a new competition to select an advanced infantry combat weapon. The armed services committee felt that the military had a fine weapon already, and decided to create an impossible set of design parameters to purposely set this weapon program back at least ten years. The first and only entrant in the competition was the M-31a1. Militech had developed a new grenade launcher firing a projectile the size of a 10-gauge shotgun shell, but with performance almost equal to standard 40mm grenades. Malorian Firearms had recently patented a new weapon system called "liquid propellant action", but didn't have the capital to develop anything beyond a working prototype. Eran Malour offered the licenseto Militech, and in just eighteen months, the M-31 AICW was in production. The M-31a1 is an over and under configuration with a 4.5mm caliber assault weapon atop a pump-action mini-grenade launcher. The liquid propellant action functions like an old-style gasoline motor in that propellant and oxidizer are mixed in a firing chamber, then electrically fired by pulling the trigger, launching a 4.5mm copper-jacketed bullet and cycling the action. The M-31a1 magazine holds 150 projectiles and the propellant necessary to fire them. Paired with the grenade launcher, this design has proven to be an efficient and deadly combination. The M-31A1 is not equipped to be outfitted with standard rifle accessories.

Source

 * Chromebook Volume 1, pg.45
 * Blackhand's Street Weapons, pg.28