Made between mid-1942 and late-1943, mainly by Lines Brothers Ltd, London. Lines Brothers Ltd, is better known for making Tri-ang toys, Meccano and Dinky.
Calibre - 9mm
Magazine capacity - 32 rds
Rate of fire - 540rpm
The Mk. 3, initially produced for the ground forces, was first issued in April 1942 and was manufactured principally by Line Brothers Ltd, of Merton, London. It was essentially an even simpler version of the Mk. 1 and was made of pressed steel, even the barrel being pressed into a rifled mandrel giving a work hardened tube that only needed the chamber reamed to complete it. The top flange incorporated the foresight with a handy aiming rib running along the top of the gun. It also had an ejection port stop to stop a user's little finger inadvertently wandering into said port and while not generally incorporated onto later Stens, was quite often added as an 'ad hoc' modification by individual users. The only downside to the Mk. 3 was that, with a non-removable barrel, wear and tear to the barrel itself or dents to the outer casing could not be fixed and so the entire gun had to be scrapped. It also featured a fixed magazine housing for improved reliability. It was the Mk. 2 and Mk. 3 Stens that would gradually take over from the Thompson in Home Guard and indeed, Auxiliary Unit service. Even the Mk.3 went on to be used by every arm of the service including the airborne forces and was even supplied to the resistance. They were dropped into Europe in a stout box containing the gun, eight magazines, a sling, pull-through and oil bottle, weight, two gauzes and a magazine filler.