The [[United States]] military started to believe in the value of the submachine gun after a successful British Sten Mark series and the famous German MP40 Submachine gun. The '''M3A1 Grease Gun''' first saw action in the European Theater during [[World War II]], though not to much fanfare. | The [[United States]] military started to believe in the value of the submachine gun after a successful British Sten Mark series and the famous German MP40 Submachine gun. The '''M3A1 Grease Gun''' first saw action in the European Theater during [[World War II]], though not to much fanfare. |