|MP18 Sub Machine Gun|
|Region of Origin:||German Empire|
|Barrel:||200 mm (7.9 in)|
|Rate of Fire:||~500 round/min|
The MP 18 manufactured by Theodor Bergmann Abteilung Waffenbau was the first submachine gun used in combat. It was introduced into service in 1918 by the German Army during World War I as the primary weapon of the Sturmtruppen, assault groups specialized in trench combat. Although MP18 production ended in the 1920s, its design formed the basis of most submachine guns manufactured between 1920 and 1960.
A common myth is that the Treaty of Versailles banned the production and use of the MP 18 by Germany. In fact, the treaty only limited the number of machine guns that Germany was permitted to stockpile, and no mention is made of machine pistols or the MP 18 in particular.
The MP 18 was a heavy weapon, weighing over 5 kg (11.0 lb) when fully loaded. The receiver tube was very thick (~3 mm), compared with later World War II submachine guns with half that thickness or less, such as the Sten gun or MP 40.
Though Schmeisser designed a conventional 20-round-capacity "box" magazine for the weapon, the Testing Commission, for practical reasons, insisted that the MP 18 be adapted to use the 32-round TM 08 Luger "snail" drum magazine that was widely used with the long-barreled version of the P 08 pistol known as the Artillery model.
Like many other open-bolt designs, the MP 18 was prone to accidental discharge. If the buttstock of a loaded gun was given a hard knock while the bolt was fully forward, the gun could accidentally fire because of the bolt overcoming the action spring resistance and moving rearward enough to pick up a round, chamber it and fire. Soldiers liked to leave the bolt of their firearm in this closed or forward position, so dirt and debris would not enter the barrel and chamber. This 'Bolt-closure' practice acted as a dust cover for the weapon's chamber, preventing a malfunction from occurring because of the presence of foreign debris, but making accidental discharge more likely.
The German police asked for an external safety on their MP 18s, and a universal bolt-locking safety was added on all the submachine guns used by the police. Later submachine gun designs like the Sten and the MP 40 were modified to allow the cocking handle to be pushed inwards to lock the closed bolt to the tubular receiver casing. This design change prevented accidental discharges when the bolt was left forward and a loaded magazine was inserted.