Suppressed Sten Mk4

The MkIV is the missing link between the most utilitarian Sten, the MkIII, and the final iteration – the wooden-stocked MkV. Very little is known about the MkIVs development and more archival research is needed.

The weapon was on display at the Morphy Auctions booth. While they couldn’t disclose which collection it was on consignment from, they noted it was believe to have been brought home by what they described as ‘a US Commando’. Not the clearest provenance but more might be explained in the auction catalogue when it publishes in a couple of months’ time.

There are several variants of the MkIV – what have become known as the MkIVA and MkIVB. This weapon is one of three examples of suppressed MkIVAs, the others are in the Royal Armouries’ collection.

*A suppressed Sten MkIVA with stock folded (Matthew Moss)*

The Royal Armouries also has unsuppressed examples of the MkIVA and MkIVB. This is an unsuppressed MkIVA. I couldn’t find any decent resolution photographs of the MkIVB but as you can see it has its pistol grip and trigger assembly moved forward significantly.

The gun appears to have been using a Sten MkII receiver and its magazine housing is marked as such. Interestingly, it doesn’t have a MkII serial number, instead it is marked ‘3’. This is similar to one of the MkIV’s held by the Royal Armouries. On the underside of the magazine housing is a further serial number ‘R83297’. Morphy’s noted that they believed the gun, or the MkII receiver used to make it, was produced by BSA.

The trigger mechanism has been moved forward about 1 inch (2.5cm) and unlike any other Sten is enclosed by a large bow trigger guard, suitable for cold weather use with gloves. The unsuppressed MkIVA has a 3.5 inch barrel tipped with a conical flash hider, however, this example is suppressed with what Peter Laidler, in his Sten book, mentions is an MG-D 3748 silencer designed by the Armament Design Department.

One of the most interesting differences is the shorter cocking handle slot in the receiver and the different design of cocking handle. The receiver has been shortened as has the Mk4’s barrel – which has six small ports drilled into it. This gun’s cocking handle is reportedly designed to be rotated 90 degrees to lock the bolt in the forward position. This is a departure from the earlier locking method of pushing the cocking handle down to lock into a hole in the other side of the receiver.

*A suppressed Sten MkIVA with stock unfolded (Matthew Moss)*

The other most distinguishable feature is the folding stock. This design is shared by the A and B variants and is made of a tick steel bar which pivots. The pivot point is in line with the front of the pistol grip. To deploy or fold the stock a small spring-loaded catch is pull towards the butt, this allows the stock to be pivoted through 180-degrees to the left. While the catch locks positively, if the small coil spring which provides tension was damaged the stock would unlock making it difficult to use. The coil spring is also exposed which could allow it to snag on things or become clogged with mud.

But who was the MkIV designed for? According to FWA Hobart’s book on submachine guns the MkIV was developed for airborne troops – a prior to this paratroops had dropped with the stock removed from their Stens. Hobart suggests that the MkIV guns were abandoned because they didn’t fare well in trials due to a high, uncontrollable rate of fire. Whatever the reason they never entered service and only a handful of prototypes were made.

Thank you to Morphy Auctions for letting me take a look at the MkIV – its set to be on sale at their upcoming Firearms Auction in April.

One thing I’m looking forward to doing this year is doing some archival work, digging into the surviving records regarding the Sten and hopefully uncovering more on the MkIV.

*Close up of the right side of the Sten’s receiver (Morphy’s Auctions)*

Update – 01/03/23: Morphy’s auction listing for the weapon has been published and offers some detail on the Sten’s origins and some excellent photographs. Below is an extract detailing the Sten’s provenance:

“This particular specimen was issued to an American officer who was training in England and was intended to be landed in Japan as part of pre-invasion operations in 1945. According to the officer at the time of the gun’s purchase, when the invasion was called off the authorities never asked for the gun’s return. The officer brought the gun back to the United States and subsequently registered it with the BATF.”

Ian over at Forgotten Weapons has also had a chance to look over the weapon and shoot it. Well worth checking those videos out.

Bibliography:

Special thanks to my friend Hrachya Hayrapetyan for helping with the ad-hoc filming of this video!

Entries in the Royal Armouries collection catalogue: 1 2 3 4

STEN MkIV (Prototype), Historical Firearms.info, (source)

Experimental STENs, Firearms Curiosa, (source)

The Sten Machine Carbine, P. Laidler, (2000)

Pictorial History of the Submachine Gun, F.W.A. Hobart, (1971)

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The STEN in the Rhineland

Earlier this year I had the pleasure of filming some segments on small arms for the new documentary on the Rhineland Campaign – ‘Rhineland 45‘. Not all of the segments I filmed discussing weapons could be included in the finished documentary – I filmed quite a few – so I’m pleased to share a couple here. This video examines the various marks of STEN gun used during Operations Veritable and Varsity. This video was filmed at the Vickers MG Collection and Research Association.

Check out the first video of this series on the use of the PIAT here and our video on the Panzerfaust & Panzerschreck in the Rhineland here.

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WW2 Makeshift Sten Foregrips

A couple of weeks ago we looked at some photographs showing an interesting modification seen on a STEN MkII held by Deputy Prime Minister Clement Attlee. The STEN Attlee posed with had a front grip added, something the MkII didn’t typically come with.

A few people very kindly sent me some other contemporary photos showing other ad hoc STEN front grips so I thought a follow up video was needed. I also found a group of photographs taken in June 1943 at the Combined Training Centre at Kabrit, in Egypt. The photos show groups of Commandos and the Royal Navy’s Naval Beach Parties armed with Stens with a pretty standardised style of front grip.

*Commandos on parade with STEN MkIIs equipped with ad-hoc front grip, at Kabrit in June 1943 (IWM A17755)*

In these photos we can see the men training with the STENs and the front grips are quite clear. It’s especially interesting in that it isn’t just the Commandos who have the front grips but also men of the Naval Shore Parties. It’s also relatively rare to see STENs in North Africa. You might have seen some of these photos, taken by Royal Navy photographer Lieutenant L.C. Priest, in our video looking at the unusual fighting knives the Commandos are equipped with.

The plethora of photos from Kabrit show a fairly standardised design for the grip. A metal ring, seemingly tightened by a wingnut on the left side and a generous wooden grip that was long enough to fit all four fingers on. The grip appears to have some finger grooves and a fairly standard shape. A photo (see above) of Naval Commandos on parade shows the men with the STENs tucked under their arms, holding the front grips. This is identical to how the STEN MkI with its front grip was paraded with. The photo also gives us a good look at the uniformity of the grips.

*RAF Regiment Corporal cleans his STEN MkII, equipped with a makeshift front grip (IWM CM4296)*

While the photos from the Combined Training Centre at Kabrit represent the largest number STEN front grips seen in one place and several units there are a few other photos which are really interesting. First up is this photograph of a Corporal from the RAF Regiment taken in Libya sometime in 1943. The Regiment had been formed just a year earlier. The corporal is sat cleaning his STEN MkII with the butt removed but the bolt still in the weapon. On the barrel nut of his weapon he has a wooden front grip. Again seemingly attached to a metal band around the barrel nut. The wooden grip appears to have some rudimentary finger grooves. Sadly, I couldn’t find any other photos of this Corporal and his STEN. But the design of his front grip is very similar to those seen in the Kabrit training photos and could well be of the same origin.

Finally, we have a photograph from a completely different theatre – Burma. The caption for this photograph reads: “Men of the 2nd York and Lancaster Regiment searching the ruins of a railway station for Japanese snipers, during the advance of 14th Army to Rangoon along the railway corridor, 13 April 1945.” This soldier’s STEN MkII has a grip just in front of the trigger mechanism cover and behind the magazine housing and ejection port. It’s actually in a position close to that of the original STEN MkI’s integral folding pistol grip.

*Soldier of the 2nd York and Lancaster Regiment with a STEN MkII outfitted with a homemade front grip, Burma 1945 (IWM SE3804)*

At the end of the day the adaptation is a good idea, a front grip provides a means of pulling the weapon into the shoulder and a more natural place to grasp other than the barrel nut, the trigger mechanism housing or the magazine – which was discouraged. It is interesting to note that I’ve yet to see any examples of a MkIII being fitted with a front grip like these.

This is certainly something I’m going to do more research into to see if there’s any documentary reference to the use of front grips like these. With the introduction of the MkV, with its front grip, it seems that the idea was sound enough. If you know of any other examples let me know in the comments!

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Clement Attlee’s Curious MkII STEN Front Grip

I was recently I was taking a look through the Imperial War Museums’ online image collection when I found a pair of very interesting photographs taken in Scotland in April 1942. They show Deputy Prime Minister Clement Attlee handling a STEN MkII submachine gun while visiting Polish troops. Most interestingly though is the folding front grip which has been added to the Sten!

*Clement Attlee with STEN MkII (Imperial War Museum)*

The MkII, introduced in August 1941, did not have a folding front grip as standard. The earlier MkI had had a front folding grip, but the MkI*, introduced in October 1942, had eliminated this to speed up production. The original caption of this photo reads:

“Mr Attlee tries the weight and feel of the Sten Sub-machine gun used by the Paratroops.”

Attlee was visiting the 1st Polish Independent Parachute Brigade during a visit to the 1st Polish Corps) at Cupar in Scotland. In the photos he’s accompanied by Colonel Stanisław Sosabowski, the commander of the brigade. In this second photograph, Attlee is holding the Sten by its trigger mechanism cover and we can see the folding grip more clearly.

It appears to be made up of a band of steel which slid onto the barrel nut housing – much like the later MkV foregrip. The grip appears to possibly pivot on a rivet and the grip itself appears to be tubular metal. Sadly the photos are fairly low resolution so we can’t see too much more detail.

These were the only two photos of the grip I could find and I haven’t yet been able to find any documentary references to them. It may be that the grip was experimental and provided to the Polish paratroops for testing or it was an adaptation unique to the unit – perhaps something the unit’s armourer made. I’ll need to do more research in the future to try and find out more about the curious STEN accessory!

For more on the STEN check out our video on the origins of the STEN and it’s name below:

Bibliography:

The Polish Army In Britain, 1940-1947 series, Imperial War Museum, H 18884 & H 18883

STEN Magazine Loaders

While the ongoing Coronavirus pandemic has prevented some archival research I had planned which would have informed much of the STEN series, our good friend Richard at the Vickers Machine Gun Collection and Research Association, has come to our aid and we’re able to cover some of the loading accessories developed for the Sten’s magazines.

As we know the Sten uses a 32-round double stack, single feed magazine which can trace its origins back through the Lanchester Machine Carbine to the Haenel MP28,II’s magazine designed by Hugo Schmeisser [patented in 1931].

Sten Magazine, inert 9x19mm rounds and MkII and MkIV magazine fillers

The nature of the single feed makes the magazine difficult to load by hand with the last few rounds very hard to insert. So a series of four marks of ‘magazine fillers’ were developed. These are described in the British Army’s official List of Changes in February 1943.

The MkI is described as consisting of “a lever mounted on a short case which conforms to the shape of the magazine. It is hand operated, the loading lever being given a rocking motion during filling. The MKI slipped over the top of a magazine with a rivetted spring tab which indexed into a notch in the front of the Sten mag.

The MkII is very similar but simplified by having the spring catch mounted on the rear instead of the side and engaged a “small rectangular slot on the magazine”. The rear of the spring is turned up slightly to allow the user to remove its from the magazine.

The MkIII, which is possibly the rarest of the fillers, is described as:

“hand operated but of different design from the MkI and MkII. It consists essentially of a spring loaded vertical plunger which is attached externally to a case, the latter to assemble on the magazine. There is no retaining catch. It comprises the following parts:
Case. Is a rectangular shaped steel pressing with a tube of rectangular section welded thereto. The latter, which houses the plunger and spring, has a hole trilled at the lower end to accommodate a pin which restricts the amount of movement of the plunger and acts as a stop for the compressing spring.
Plunger, loading. Is made of two laminated steel strips welded together the top part of which is set to form a handle. The body of the plunger is slotted to accommodate the compression spring. The top part is splayed to form a suitable contact with the cartridge.”
List of Changes, Feb. 1943

Sten accessories including a sling and a MkII magazine filler

The other more common filler is the MkIV. Which is a much simpler design with a loading lever mounted on top of a clip which is attached to the rear of the magazine body and retained by a spring similar to that of the MkII.

Rich has very kindly demonstrated the use of the two most common fillers – the MkII and the simpler MkIV. It takes Rich just under 2 minutes to load that magazine, but he was doing his best to show various angles and unlike a British soldier during the war he hasn’t regularly loaded magazines with one of these fillers either. Despite that the clip gives a good idea of how fast you could load a mag once you’re in the groove.

With the MkIV filler Rich was able to load the mag in about 1 minute 15 seconds, the stability of resting the base of the mag on the table helped with the MkIV’s simpler design.

Manual diagram showing both the MkII and MkVI

Also, as a follow on to our previous episode looking at the Sterling Submachine Gun’s magazine Rich has also demonstrated the loading of a Sterling mag to its 34 round capacity. No magazine filler needed with George Patchett’s double-stack, double feed magazine.

Massive thanks to Richard for taking the time to film the clips used in the video. please do go and check out Richard’s channel and www.vickersmg.org.uk.

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The Sten Gun, Its Name and the Men Behind It

The Sten is one of Britain’s iconic Second World War Small arms. Two men are principally responsible for its development Colonel Reginal Vernon Shepherd and Mr. Harold John Turpin a pair of small arms and engineering experts with considerable experience.

Turpin was born in Kent in 1893, served his apprenticeship as a draughtsman in Erith and in 1922, he joined the drawing office at the Royal Small Arms Factory Enfield – Britain’s principal state small arms centre.

Reginald Shepherd was born in 1892, received an Bachelor of Science Degree from Leeds University in 1912. In October 1914, he joined the West Yorkshire Regiment as a second lieutenant, serving in Gallipoli and Egypt. After the war, with his engineering background, he assigned as 2^nd Assistant Superintendent at the Design Department at RSAF Enfield in December 1922, and promoted to captain.

The two men found themselves joining Enfield at around the same time. In November 1933, Shepherd, now a major, was appointed Inspector of Small-Arms (Class 2) at Enfield and assisted in getting the Bren light machine gun into service. He remained at Enfield until 1936, when he retired from the army and spent a short spell at BSA before being recalled. In late 1939, Major Shepherd returned to active service and once again took up the position of Inspector of Armaments, this time at the Ministry of Supply Design Department at Woolwich Arsenal.

RSAF - Ra — Inside RSAF Enfield (Royal Armouries)

By the outbreak of the Second World War Turpin had become the senior draughtsman at Enfield and when the development of the Lanchester Machine Carbine began he was paired with Major Shepherd to draw up technical drawings for the gun’s production.

The two men decided that a simpler, cheaper submachine gun could be produced and in December 1940 set about designing it, with Turpin in the lead. During the Winter of 1940-41 the first prototypes were built. Development of the first Sten – the T40, was completed on 8^th January 1941, taking just 36 days.

14 pilot models were ordered but only two were completed by engineers at the Philco Radio Works in Middlesex: T-40/1 and T-40/2. The gun was initially designated the ‘T-40’ or Turpin, 1940. By the end of January 1941, it had become known as the ‘ST Machine Carbine’. The ‘Carbine, Machine, STEN, MkI’ was approved for issue on 7^th March, 1941, with 100,000 guns ordered.

How did the gun become known as the ‘STEN’ and what did Sten stand for?

We know that the ‘S’ stands for Shepherd and the ‘T’ for Turpin, but what about the ‘EN’ – it is generally accepted to represent ‘Enfield’. Why? Because RSAF Enfield is synonymous with British military firearms. Additionally the Bren light machine gun’s name is a portmanteau of ‘BR’ from Brno, the location of the Czech factory the zb.26/30 originated from, and ‘EN’ for Enfield, the British factory that anglicised the design for British manufacture and service.

Enfield, however, wasn’t where the Sten was designed. Turpin and Shepherd claimed that most of the work on the design had been done out of hours. Additionally, during the winter of 1940, the Armament Design Department was relocated, from Enfield to a former Drill Hall in Cheshunt, Hertfordshire to escape the bombing of London.

While the Sten may not have been designed at Enfield, the first prototype was partially assembled there with work also done at Turpin’s own home workshop. A further 46 pre-production pilot models were later ordered from RSAF Enfield, in February 1941.

name insert

Intriguingly, early accounts suggest that ‘EN’ may have stood for ‘England’ – not ‘Enfield’. In October 1942, the fifth instalment of ‘Know Your Weapons’, a semi-official series of weapons manuals printed by the publisher Nicholson & Watson, explains that ‘EN’ did in fact stand for ‘England’.

In June 1943, Turpin penned a semi-anonymous article for ‘The Model Engineer’, about the design and development of the gun, which repeated this claim. An October 1943, article in the US Popular Mechanics magazine, entitled ‘Machine Guns from Backyard’, includes a supposed quote from the inventors explaining that the “E and N stood for England.”

585369 — ‘The Sten Carbine’, *Model Engineer*, Turpin, June 1943

A more official account came in June 1949, at a hearing of the Board of the Royal Commission Awards to Inventors (a board set up to reward inventors who had done important war work). One of the board members Lord Justice Sir Lionel Cohen asked Shepherd: “Why was it called the Sten?” The colonel replied: “It was called the Sten by the then Director General of Artillery. The ‘S’ was from my name, the ‘T’ from Mr. Turpin, who was my draughtsman and who did a very large amount of the design, and the ‘EN’ was for England. That is the origin of the name, for which I accept no responsibility.” This suggests that the ‘EN’ standing for ‘England’ may have originated from the upper echelons.

Sadly, there was no officially published explanation of the name as official manuals rarely go into superfluous detail. In 1948, however, Ian Hay published R.O.F. The story of the Royal Ordnance Factories, 1939-1948 in which he stated the ‘EN’ was a reference to the Enfield factory. Similarly, another early published account, D.M. Ward’s 1946 The Other Battle, a history of BSA, also suggested it represented the factory name.

In truth it is difficult to know exactly what the ‘EN’ stood for. It may be that both Enfield and England were discussed and used by various individuals and offices. There may have been an element of propaganda to including ‘England’ in a weapon’s name which led senior officers to push this in the press and direct the gun’s inventors to suggest this was the case too. Of course the authors of those earlier books may have mistakenly believed ‘EN’ stood for Enfield, as it does in Bren. Personally, I’m inclined to follow the primary sources attributed to the two men responsible for the design, and believe it initially stood for England.

Other War — *The Other Battle*, D.M. Ward, (1946)

Shepherd was awarded an OBE in January 1942, and became the Assistant Chief Engineer Armament Design (A/CEAD), he was promoted to Lt. Colonel in August 1943. He retired from active duty at the age of 55, in January 1947, and was removed from the reserve list. He was granted the honourary rank of colonel. He died in April 1950, aged 58. Turpin retired from RSAF Enfield in 1953, and died in April 1967, aged 74.

Beyond a pair of discretionary payments, £1,500 to Shepherd and a small payment of £200 to Turpin, neither man was officially rewarded as they were deemed to have essentially done what they were paid for, designing small arms. Scant reward and recognition for a weapon which became one of the key wartime small arms of the British and Commonwealth forces.

Our thanks also to Jonathan Ferguson, of the Royal Armouries, for sharing his thoughts on the ‘Enfield’ vs ‘England’ debate.

Bibliography

The Sten Machine Carbine, P. Laidler, (2000)
R.O.F. – The Story of the Royal Ordnance Factories, 1939-1948, I. Hay, (1949)
The Other Battle, D.M. Ward, (1946)
The Sterling Submachine Gun, M.J. Moss, (2018)
The Sten Gun, L. Thompson, (2012)
‘Sten & Bren Guns’, Know Your Weapon #5, (Oct. 1942)
‘The Sten Carbine’, Model Engineer, 3 Jun. 1943, H.J. Turpin
Board of the Royal Commission Awards to Inventors – 1946-49
‘Machine Guns From Backyard’, Popular Mechanics, Oct. 1943

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Hybrid Sten

During our first research trip last spring I had the opportunity to examine an unusual ‘hybrid’ Sten submachine gun. The weapon combined a MkII Sten’s receiver with a MkIII’s magazine housing. Added to this was a proprietary folding stock and a new fire control group and pistol grip.

Very little is known about the hybrid Sten with Peter Laidler’s book The Sten Machine Carbine mentioning it and the later Osprey book by Leroy Thompson sharing a photograph and brief caption which calls it an “experimental version of the Mk III.” It is also unclear exactly when it was built.

Below are some photographs I took of the Sten, lets look at some of the interesting features of the Hybrid Sten.

left side of the Sten with the stock folded flush under the receiver (Matthew Moss)

No production Variant of the Sten was fitted with an under-folding stock, the Australian Austen, however, directly copied the MP38/40. The entire weapon is covered by a layer of textured, crackle paint finish, this was commonly used on commercial Sterling Mk4 submachine guns. The weapon has a short, 3.5 inch, perforated fore-end welded onto the front of the tube receiver that appears to be from a Lanchester.

Rear right of the weapon close up of its pistol grip, stock and trigger housing (Matthew Moss)

The under folding stock is rudimentary but effective, the butt plate swivels free but the lock up is quite secure. It uses the receiver main spring-loaded return-spring cap. The folding stock attaches to the pistol grip assembly (which can be seen detached below).

The proprietary rectangular trigger group housing brazed onto the tub receiver is unlike any other Sten and lacks a fire-selector.

Left side of the Sten with its pistol grip and stock assembly detached (Matthew Moss)

The pistol grip itself is made from paxoline, a form of early resin plastic. The shape shape of the pistol grip does not resemble any production or prototype Sten grip. A simple hand-stop, made from a bent piece of sheet metal, has also been added in front of the weapon’s ejection port to prevent the user’s hand moving back and fingers being caught if gripped by the forend.

Right side of the Sten with its stock unfolded (Matthew Moss)

While the origins of the hybrid Sten remain unclear I don’t believe it was an officially made prototype. While impressive it is relatively crudely assembled and does not match the Sten prototypes made by Enfield, such as the VI. Intriguingly, the magazine housing of the weapon has been stamped ‘PILOT’ below the usual ‘STEN MkIII’ stamp. I suspect that the weapon may have been put together by a unit armourer, perhaps authorised by a superior officer to suggest improvements or as an unofficial project gun.

UPDATE: Their is some evidence emerging that this Hybrid Sten may be related to the T42 Sten prototype, part of the Sten MkIV development program. Where this hybrid fits into the story is not yet clear but the similarities are striking, when we have more information we will revisit this weapon.

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Technical Specifications:

Length (with stock folded): approx. 40cm (30in)
Weight: approx. 3kg (7lb)
Barrel Length: 16cm (6.5in)
Action: Blowback
Calibre: 9x19mm
Feed: 32 round box magazine
Cyclic Rate: approx. 500 rpm

Bibliography:

The Sten Machine Carbine, P. Laidler (2000)

The Sten Gun, L. Thompson (2012)

Please do not reproduce photographs taken by Matthew Moss without permission or credit. ©The Armourer’s Bench 2018.