Machine Gun. Machine guns needed 4-6 men to work them and had to be on a flat surface. They had the fire-power of 100 guns. Large field guns had a long range and could deliver devastating blows to the enemy but needed up to 12 men to work them. Submachine Guns. The Germans first introduced the MP18 Bergmann Muskete submachine gun – called a "machine pistol" – in 1918, in the closing months of World War I. The light-weight weapon had a rapid rate of fire and was easy to use in trenches and other confined spaces.