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.

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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.

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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.

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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.

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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.

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.

FAMAE PAF Submachine Gun

The 1960s and 70s saw Chile was racked by political turmoil with a military junta, led by General Augusto Pinochet, taking control in September 1973. Pinochet’s Junta took control of the country via a bloody coup, overthrowing President Salvador Allende, and as a result all export of small arms from Britain to Chile ceased. In the early 1970s, before the coup d’etat, The records of the Sterling Armaments Company show Chile purchased an example of the company’s Mk4 submachine guns and no less than 101 suppressed Mk5 Sterling-Patchetts.

With the import of small arms from the UK and other countries banned by an embargo Chile’s government were eager to increase their self-sufficiency.  As a result in the mid-1970s the state-owned firearms manufacturer Fábricas y Maestranzas del Ejército (FAMAE) experimented with copying the Sterling Mk4 in an effort to minimise development costs.

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Left-side view of the PAF with its stock extented (Matthew Moss)

The resulting 9x19mm submachine gun was dubbed the PAF or ‘Pistola Ametralladora FAMAE’. It took the basic Sterling design and simplified it. The PAF lacks the Mk4’s perforated barrel jacket and instead has an exposed barrel, tipped with a rudimentary spoon-shaped compensator. It also lacked the Sterling’s folding stock, instead it had a simple collapsing stock. As a result, the disassembly catch has been moved 90-degrees to the left side of the receiver.

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Right-side view of the PAF (Matthew Moss)

Like the original, the Chilean copy retained the dirt-clearing grooves cut into the weapon’s breech block. The PAF’s plastic charging handle and butt stock shape are reminiscent of the Heckler & Koch MP5 – although much cheaper feeling in quality. The profile of the PAF’s pistol grip is slightly different but the weapon still fed from standard 34-round Sterling magazines. Interestingly, unlike the Sterling’s screwed-in-place barrel, the PAF’s was held in place by a machined barrel nut – in terms of production this is a much simpler system, no doubt borrowed from the Uzi.

The Chilean copy weighs significantly less than the British original, 2.5kg (5.5 lbs) and reportedly has a much higher 800 rounds-per-minute rate of fire. In general the PAF looks much like Sterling’s own later Para Pistol model, the Mk7.

Some sources suggest that only a small number of toolroom prototypes were made, although the relatively high serial number, #00748, of the example we looked at may indicate a limited production run may have been produced. It is clear, however, that the PAF did not go into general production. Instead, FAMAE later focused on weapons derived from Swiss small arms including the SIG SG 510 and SIG SG 540, and the SAF submachine gun introduced in the 1990s.

Note: The PAF was the last weapon we filmed during this particular research trip and we did not have time to film or photograph the PAF’s internals (we filmed a lot of videos that day and were pressed for time). Rest assured if and when we get the opportunity we will update this article with photographs of the weapon disassembled!  

Technical Specifications:

Length (with stock collapsed): approximately 44cm (17in)
Weight (unloaded): 2.5kg (5.5lb)
Barrel Length: 17.5cm (6.9in)
Action: blowback, open bolt
Calibre: 9x19mm
Feed: 34-round box magazine
Cyclic Rate: suggested ~800 rpm


Bibliography:

The Guns of Dagenham, P. Laidler & D. Howroyd, (1995)

‘The PAF: Chile’s First Indigenous Submachine Gun’, TFB, R. Olive (source)


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

AUSTEN Submachine Gun

At the beginning of the Second World War the Australian Army, much like Britain, lacked a standard issue submachine gun. Following Britain’s lead a small number of Thompson submachine guns were ordered for trials purposes in early 1941. The Australian military eventually purchased 18,382 Thompson M1928A1s, however, it was realised that an indigenously produced weapon was needed.

1941 saw extensive testing and development of Evelyn Owen’s submachine gun, at the same time technical drawings for the Sten arrived from Britain. The Australian engineers that examined the Sten believed that it was too rudimentary for Australian needs. In September 1941, the Melbourne-based Die Casters Ltd. were contracted by the Ordnance Production Directorate to investigate improving the Sten. W.T. Carmichael & Sons Ltd were also interested in producing submachine guns and both Carmichael and Die Casters were contracted to produce the improved Australian Sten gun.

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Austen-armed Paratrooper from the Australian parachute battalion training centre, c.1945. The Austen’s folding stock made issue to paratroops one of the few roles that the Austen was better suited to than the Owen gun (AWM)

The Austen was based upon the MkII Sten, however, substantial changes to the design were made. These included a new folding stock based upon the German MP38/40 stock, an added forward pistol grip and a cocking handle slot which ran almost the full length of the tub receiver. This longer slot opened allowed greater ingress of mud and dirt. The most significant internal change was the use of the MP40’s bolt and telescoping return spring. The magazine housing was die cast while the rest of the weapon’s parts were stamped steel. Some aborted attempts by Die Casters Ltd to incorporate die casting production methods lead to early failures but by early 1942 the weapon was ready for production.

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A close up of the Austen’s Diecast magazine housing (RIA)

Like the Sten, the Austen was a simple blowback submachine gun, chambered in 9x19mm and feeding from a 32-round magazine which fed horizontally from the left. With its stock folded it was 52cm long and weighed 3.9kg (8.8lb) unloaded. By contrast the heavier but more reliable Owen weighed 4.2kg (9.3lb). The Austen’s fixed rear aperture sight was fixed at 100 yards.

The new folding stock increased the weight of the Austen, it was also slightly longer than ideal in order for the butt plate to clear the forward handgrip. Some troops complained that this made the weapon’s length of pull too long. In general the Austen required more parts and was more expensive and complex to manufacture. Some Sten parts were interchangeable with the Austen, as were Sten magazines. Like the Owen it appears that at least some Austens were fitted with suppressors similar to that of the Sten MkII(S) and MkVI.

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The photograph above shows Lt.Colonel Tucker, commanding officer of the 2/23 Infantry Battalion, testing a suppressed Austen in Borneo in September 1945. Note also the suppressed Owen Gun in the background (AWM)

As Australia was in desperate need of submachine guns both the Owen and Austen were ordered into production. The Austen, however, suffered from a series of delays and quality control issues. As a result only 2,100 Austens had been issued, out of over 16,000 made, to troops by early 1943. In total 19,914 Austens are thought to have been built, most of these were factory spray painted with a camouflage pattern (see image #3)  In contrast 45,400 Owen guns were produced by June 1945. The Owen was certainly favoured by troops in the field. A report written following troop trials with 300 Austens noted that the weapon’s working parts were exposed, it didn’t function as well as the Owen after submersion in mud and water, it lacked a flash-hider, its stock was too long and was less accurate than the Owen. The Owen, while heavier, was appreciated for its reliability, ergonomics and balance.

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Australian women war workers pose with an Austen (AWM)

Attempts were made to produce an improved MkII Austen, which used more die cast parts, however, this was not adopted and only 200 were made. By the end of the war the Austen had been removed from frontline service and placed in reserve. Dutch troops in the Dutch East Indies (present day Indonesia) also used a number of Austens during the Netherlands’ period of decolonisation in the region between 1945-1949. The Owen Gun continued to be used into the 1960s, seeing action in Korea, Malaya and Vietnam before it was replaced by the F1 submachine gun.

Technical Specifications:

Length (stock unfolded): 73cm (29in)
Weight (unloaded): 4kg (8.8lb)
Barrel Length: 20cm (7.8in)
Action: Blowback, open bolt
Calibre: 9x19mm
Feed: 32-round box magazine
Cyclic Rate: ~500rpm


Bibliography:

‘Australian SMGs During WWII’, The Armourer, K. Driscoll

The Sten Gun, L. Thompson (2012)

Owen and Austen – The WW 2 ‘Aussie’ Machine Carbine Story, G. Barber, (source)

The Owen Gun, W. Wardman, (1991)