Origin: United Kingdom
Year: 1941
Type: Submachine gun
Caliber: 9mm Parabellum
Weight: 3.2 kg (7.1 lb)
Length: 762 mm (30.0 in)
Barrel length: 197 mm (7.8 in)
Capacity: 32 rds

In the early years of World War II, the British military was in dire need of weapons, including submachine guns, to equip its troops. While domestic weapons such as the Lanchester and imported weapons such as the Thompson were entering service, a shortage of small arms still remained. A shortage which was made worse following the losses of equipment during the Battle of France. A new, easily and cheaply manufactured submachine gun was required. Designed by Major R.V. Shepherd and Mr. Harold Turpin of the Royal Small Arms Factory at Enfield, the Sten answered the call. The Sten submachine gun's design was such that it could be made by small machine shops which lacked the equipment necessary for more complex designs, such as the Thompson. This simplicity also lent the design to clandestine manufacture in occupied Europe for use by resistance groups. It was also extremely cheap to build with a cost of approximately $10 per unit compared to $209 for a Thompson M1928A1 or $45 for the simplified Thompson M1A1.

Though inaccurate due to its short barrel and blowback-operated open bolt design and suffering from reliability and safety issues (including the possibility of the weapon chambering and firing a round if bumped hard enough with a loaded magazine and closed bolt), the Sten proved to be the weapon Britain needed at the time. While many variants were developed, the Mk II was the most widely produced and eliminated such features as a forward grip and a flash suppressor found on the original design and was fitted with a simple metal strut for a stock. As many as 4.6 million Sten submachine guns of all types were manufactured and saw service with the British military through World War II and the Korean War before being replaced by the Sterling submachine gun in 1953. Sten clones were also manufactured by Canada, Australia, Nazi Germany, Poland, Israel, and others. Stens were used in the assassination of Reinhard Heydrich (though the gun misfired) as well as the assassination of Indira Ghandi, during the Israeli War of Independence, the Troubles in Northern Ireland, and the Chinese Civil War among many other conflicts.

While the stance shown here is commonly associated with firing the Sten, with the support hand gripping the magazine, it is not the recommended/proper way of firing the weapon. With this stance, it is more likely that the weapon will jam due to misalignment of the magazine and possibly wear/stress on the magazine catch. Instead, one should hold the weapon in the same manner as a rifle and leave the magazine free.