The Legends M3 Grease Gun from Umarex Airguns is based on the M3A1 variation used from 1944 and beyond. Underneath the dust cover resides the bolt and its cut-away thumb charging slot. This blowback action SMG does fire from the open bolt just like the M3 firearms did. Noteworthy features include the collapsible wire stock, drop-free 60 round magazine, fixed peep style sights, and a 1,050 BB per minute rate of fire. Like other Legends SMGs, the M3 Grease Gun is powered by (2) 12-gram CO2 cartridges. Expect to shoot approximately 120 BBs (three magazines) for each full CO2 charge.