The Army's MK-19 weapon system is an automatic grenade launcher capable of destroying thin-skinned vehicles and dismounted targets at ranges up to 2200 meters. Since its first use in the 1960s, the MK-19 has remained largely unchanged while technology has improved. This research will determine if an alternative weapon system provides a significant improvement in lethality over the MK-19. The Joint Combat and Tactical Simulation (JCATS)is used to test weapon variants against a variety of enemies in terrain similar to current operating environments. The results of these tests