budget 2011, page-5

"Multi Shot Grenade Launcher - Additive weapon system to the USMC arsenal to provide a semi-automatic, revolving action, shoulder- fired, 400 mm grenade launcher capable of firing six rounds in three seconds to support Infantry Squads. It will be fielded to support convoy operations at the Division, Regimental, and Battalion level."



6 shots revolving action, doesn't sound like a metalstorm weapon..