Sten

The Sten was designed in 1940 by Major Reginald Shepherd and Harold Turpin at the Royal Small Arms Factory, Enfield, as an answer to a specific shortage: after Dunkirk, Britain had lost most of its stock of submachine guns and could not import the American Thompson fast enough, so the Sten was built from the outset to be produced in huge numbers by unskilled labour and small subcontractors using stamped sheet steel, a plain tube receiver and the fewest possible machined parts. Its name is an acronym of its designers’ initials and Enfield.

That production-first design meant the Sten could be, and was, built far outside conventional arms factories — by furniture makers, small engineering shops, and in occupied Europe by resistance groups working from parts smuggled in or improvised locally. Alongside Royal Small Arms Factory Enfield itself, wartime production was spread across firms including BSA, several Royal Ordnance factories, the toy manufacturer Lines Brothers, and Long Branch Arsenal in Canada, an unusually wide manufacturing base for a service weapon of the period. Several million were built across a series of marks, from the austere, unfinished-looking Mk III to the Mk IIS, a purpose-built suppressed version used by special forces and resistance fighters for its quiet, subsonic report when firing 9mm ball ammunition.

Mechanically it is a simple, open-bolt blowback design, feeding from a horizontal side-mounted 32-round box magazine derived from the German MP 28’s magazine — a layout inherited from an existing design rather than developed from scratch, in keeping with the weapon’s wartime urgency. It saw continued service and irregular use for decades after 1945, including with forces and groups well beyond the British Commonwealth.

The figures in this entry describe the Mk II, the most numerous of the Sten’s marks; other marks differ in weight, length and finish, which this single entry does not attempt to capture individually. Every figure comes from Wikipedia’s infobox rather than a primary source, and none of it carries an inline citation there except for the effective range, whose cited source no longer resolves — so all figures here are recorded as estimated. No published muzzle velocity could be tied to a stated barrel length by any source found, so none is recorded, and total production is published only as a range depending on source; the low end of that range is recorded here.