During the Great War, Germany had demonstrated the advantage of a light portable machine gun during their 1918 Spring Offensives with the introduction of the Bergmann MP 18, issued to special assault troops. After the War, Britain and other countries continued to show interest in the sub-machine gun. However up to the outbreak of the Second War, the British General Staff considered there was no need for such weapons, continuing to favour the longer range and lethality of rifles. On the outbreak of war, following the success of the German MP38, the British Expeditionary Force urgently requested sub-machine guns. The preferred choice of the British was the Finnish Suomi, also produced under licence by Sweden, but it was considered that it would be difficult to obtain as Finland was fighting against Russia and Swedish production capabilities would probably not meet the demand. As a result the American M1928 Thompson was adopted. From April 1940, some 107,000 were ordered from the U.S., eventually reaching 300,000. Only a third of these ever reached the UK, some 100,000 said to have been sunk on a single ship by a U-boat and also American rearmament meaning priority going to their domestic needs. By the end of 1940, only 107,500 had been received by Britain.
The Thompson, designed by General John Thompson as a means to give the infantryman more fire power, first entered production in 1921. The gun adopted by Britain was the 1928 model (M1928). It weighed 10 lbs and had a length of just less than 3 ft. It had a rate of fire of 650 rounds per minute. It was supplied with either a drum magazine which held 50 rounds or a box magazine which held 20 rounds. It had an adjustable backsight, giving sights from 0 – 600 yards. It fired .45” rimless cartridges.
The Home Guard Auxiliary Units were some of the first to see the Thompson sub-machine gun as GHQ prioritised supplying these units with the best equipment available. However in the regular Home Guard, units did not start to receive Thompsons until 1941. Numbers peaked at 43,017 issued by April 1942 when they were then rapidly withdrawn to be issued to the Field Force and replaced by the Sten gun.
Following Dunkirk, there was an obvious need for a cheap, mass produced infantry weapon. The Thompson sub-machine gun, although portable and capable of delivering a high volume of close range fire, was an expensive weapon for the British government to buy. A simple design, originating from Enfield that could be produced using stampings, relatively unskilled labour and a minimum of machining tools was tested and ready for manufacture by early 1941. This was the Sten gun, its name originating as follows: S – from the name of Maj Shepherd, Inspector of Armaments in the Ministry of Supply Design Department at the Royal Arsenal; T from H.J. Turpin senior draughtsman at Enfield and designer of the gun; EN – ENgland or perhaps ENfield.
There were a number of models of the Sten; in terms of issue to the Home Guard the Mk II and Mk III are the relevant models. The Sten both met a tactical need for such a weapon in the Home Guard and also allowed every man to be armed if rifles were unavailable.
The origins of the Mk II was to make the gun suitable for airborne troops; this was achieved by incorporating a quick release butt and barrel along with a rotating magazine housing which allowed the gun to be stored easily in a harness or “leg bag”. In total, 2.6 million Mk II’s were manufactured between 1941 and 1943. The MK III was manufactured by Line Bros and was stated to be an improved version as it could be made from stampings with holes pre punched. It featured a simplified body which was pressed and seam welded along the top. It still incorporated a quick release butt, but the barrel could not be removed and the magazine housing was fixed by a weld onto the body. A total of 876,794 Mk III’s were produced between 1942 and 1943. Both Mk II and Mk III’s were issued in substantial numbers to the Home Guard.
The forth edition of the “Sten Machine Carbine” pocket booklet published by Bravon Ledger Co. notes the advantages of the Mk III:
“This model embodies a number of improvements designed chiefly to facilitate handling.
1. The weight of the Carbine is reduced to 6 lbs. 8 ozs. The length (overall) is unaltered.
2. The barrel is not detachable and the barrel locking nut and catch are replaced by a barrel cover (or jacket) extending to within 1” of the muzzle. This provides a much improved forehand grip and a projection, immediately in front of the ejection opening, removes the danger of the fingers being inadvertently placed through this opening.
3. The foresight of blade pattern is set on the front end of the barrel cover thus lengthening the sight base to 16 ½ “.
4. The trigger mechanism cover is now sprung on and off and the screws are no longer required.
5. The internal mechanism is unaltered.
6. The change lever is now more certain and effective in its movement of the trip lever.”
Above: Sten Mk III
The Sten fired all types of 9mm round nose rimless ammunition. The gun was charged by blow-back and return spring. It could be fired automatically or in single shots. The automatic rate of fire was 525 rounds per minute. The magazine was a box type which held 32 rounds. About eight to ten magazines could be fired off continuously before the gun got too hot to hold. Sights were fixed for use up to 200 yards, although the Home Guard were trained for ranges of up to 40 yards (most effective at 10-20 yards) only as experience had shown these were this was the most useful.
The defensive positions that the Home Guard manned had, as part of their garrison, parties of men detailed off for patrolling and offensive defence. Such parties required close range weapons capable of a high volume of fire. The “Sten Machine Carbine” pocket booklet stated:
“The Home Guard will realise that its fire power has been considerably increased by the introduction of this, its latest weapon.”
Home Guard Tactical Instruction No 51 Part IV stated the following as the tactical role of the Sten in defence:
“The use of the Sten may be likened to an extended bayonet. To arm the battle platoon as laid down in Home Guard Instruction No 51, part II, Sec. 5. To protect sub-artillery and MMG positions. To arm DRs and Home Guard MT companies”.
Home Guard Instruction No 51. Part II recommends for the battle platoon that the platoon leader should carry a Sten, pistol or rifle and in the Rifle Group, the Squad commander should carry a Sten, No. 2 rifleman a Sten or rifle and No. 2 bomber a Sten , rifle or shotgun. The exact weapons to be carried by each platoon would ultimately depend upon their operational role.
The Sten was especially useful to Home Guard units that would be involved in patrolling in towns; Home Guard Instruction No 51 Part III states:
“Close range weapons which are easy to carry are best suited to patrols in towns. As many Stens and sawn-off shot guns as possible should be carried”.
In general, all patrolling was carried out with men as lightly equipped as possible, compatible with the task they had to perform. Again Home Guard Instruction No 51 Part III notes:
“Frequently only close range weapons, e.g. Stens, shotguns, grenades and bayonets will be carried”.
The Sten was no doubt regarded with mixed opinions in the Home Guard, just as it was in the regular Army. It could be dangerous to the operator if handled carelessly. Initially, the only safety position was a safety slot in which the cocking handle was placed; if the cocking handle was jarred from the slot the gun could go off. Later an additional safety was introduced with a push-in safety which secured the bolt to the tube receiver via a stud passing into a hole drilled through the other side of the casing. The magazine was prone to jamming if dirt got into it or the magazine got a small dent (this was due to the magazine design which merged two rows of cartridges into one row for feed). In the heat of the moment it was all too easy to grab the magazine with the left hand while firing, which could also lead to magazine jams, instead of holding the gun by its body forward of the ejection port. But, if handled correctly, the gun admirably performed its function as a close support weapon and was the perfect weapon for the Home Guard for fighting in urban areas or patrolling and ambush. Because it could be massed produced cheaply it also meant everyone in the Home Guard could be armed.