The WALTHER HK MP5 is a submachine gun that was designed by German arms manufacturer and weapons designer Heinrich Vollmer in the late 1960s and early 1970s. The MP5 was designed to replace the MP 43, which was a successful submachine gun in German service, but was rather heavy and had a relatively slow rate of fire. The MP5 is a lightweight weapon, weighing around 2.2 kilograms with a barrel length of just over 100 millimetres. The MP5 is fed by a 20-round magazine and fires 9mm Parabellum rounds at a rate of around 800 rounds per minute which is more than enough for most civilian and law enforcement use.