Islander SMG concept

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Feb 11, 2008
World traveler
So, while lots of folks in the Concept design for a modern Sten thread had mixed feelings about the basic premise, the consensus of those who responded on the design questions was that the basic Sten design is still the best way to go for a low-tech, low-cost machine-shop approach.

I should add that I am a big fan of the Australian Owen gun, which while it was expensive to make with a lot of machining did have some great features and was much liked by those who carried it. I especially like the Owen gun's attention to fighting jams from sand and dirt by using a separate cocking handle to eliminate the cocking handle slot near the bolt, and the top-feed magazine which means any dirt that does get it tends to fall out the ejection port. I admit that the magazine placement is awkward, but it does allow downward ejection, and that suggests a bullpup, hmmm....

So how about a Sten Mark III-type design with some Owen influence: a basic Sten-style tubular receiver, open bolt, blowback action with advanced primer ignition; M3 Grease-gun style dual guide rods and recoil springs; Owen-style top-loading magazine and downward ejection; forward mounted cocking handle with pushrod to bolt and pistol-grip/trigger assembly. A straight-line set-up makes it easier to control on full-auto, though it does require high-mounted sights, and we need a real safety since the cocking handle is no longer on the bolt.

With apologies to the late Evelyn Owen, here are a couple of illustrations. The Islander images, you can see, were made by playing with a photo of an Owen gun and yes, some of the images are mirrored so ignore the cocking handles on the wrong side, etc.

First illustration: Islander traditional layout, Owen Mark 1-43, F1 (an "Owenized" Sterling for the Aussies) and Sten Mark III.

Second illustration: Islander traditional layout vs. bullpup. Both have the same barrel length, the bullpup obvious gives up a lot of sight radius in exchange for a much shorter length, and I reversed the magazine catch so you don't bump it with your nose.

OK, flame away! :D


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buzz knox, the Sidewinder is new to me. I found one tiny pic on the internet, but that's it, do you have or can you point me to any more info?
There's not a whole lot of info on it on the 'net. I believe Small Arms Review had an article on it, and it's in U.S. Submachineguns. If memory serves, it was a subgun optimized for very close quarters. The original had no sights with sights (such as an occluded eye gunsight) being added later. It had a rotating mag well so left or right hand shooters could use it.

According to some reports (the accuracy of which I can't vouch for), one prototype was sent to Bragg for testing, and may have ended up on the rescue mission into Iran.

The Sidewinder never made it much past the development stage. It did make an appearance as the SMG of choice in the Liberty Corps series by Mark Roberts.

One of the early Soldier of Fortune magazines from Robert K Brown ( late 1970's)had an article on the sidewinder. I seem to recall the cover featured someone with one in each hand trying to look scary.

They were basically cheap arm guns.

USAF was looking at an arm gun for a survival/personal defense weapon and had some little guns made up in
.221 Fireball and full auto at a very high rate of fire.

This began an interest in and attempts to attract business to arm guns. The best and one that sold most on the civilian market was the Bushmaster, think AR trigger group in a non AR reciever with an AK-ish gas system. I thought they were fun, but did not spend my money on one.

BTW Bushmaster (no idea if there was any real relation to the current firm) built a rifle version of the arm gun without the forward placed pistol grip or rotating features of the Arm gun. They also used a Non AR reciever with AR trigger parts and controls, an AK like gas system, and featured a folding stock. I think there main selling points were that they were cheaper than ARs at the time and not an AR. They tended not to wear well in my limited experience. They used regular AR mags without modification. Also AR bayonet.

I wanted to see one of the pistols as a stocked pistol/SBR with a folding or slidding stock

The sidewinder IIRC was basically a Sten with a forward pistol grip and trigger with a long trigger bad back to the normal sear and such. There was no butt stock and it was fired one handed with the reciever along the forearm.

-Bob Hollingsworth
IIRC, the Sidewinder was basically killed by the Hughes Amendment. Think that article was in a 2005/2006 issue of SAR, but I could be off. It's definitely been at least two years since it was printed.
Never understood the sideways or vertical magazine on top.

Prone with a 32 round 9mm mag that is straight down (like the MP40, MP41, M3a1 Grease Gun, etc) are not as easy as a vertical or horizontally oriented magazine.
...the Australian Owen gun, which while it was expensive to make with a lot of machining ...

Huh? The Owen was a simple design produced quickly and at exceedingly low cost by a factory not originally set up to make firearms, thus leaving Lithgow Small Arms Factory's production capacity for producing rifles. They cost the Australian government one tenth the price paid for Thompsons, and far outshone the Thompson - the Sten too for that matter (as well as the Austen, the product-improved Australian version) - for reliability under adverse conditions.

Never understood the sideways or vertical magazine on top.
As well as making it easier to crawl through undergrowth and fire from a low prone position, one of the other big advantages of the top-mounted mag was that it allowed gravity to assist the process of feeding and ejection, rather than working against it, a big factor in the Owen's tremendous reliability under the worst conditions (clever design to keep dirt out of the receiver being another big factor).
Daniel, I agree with you completely on the advantages of the Owen, but if you look at the design it did involve substantial machining compared to the stamping and welding of the Sten or M3 Grease Gun. While much cheaper than a Thompson, the Owen was also much more expensive than the other two. Owens may have looked primitive, but they were well and carefully made, parts were fully interchangable, and that costs.

Here's a great site on the Owen Machine Carbine as it was properly called.
I've looked over all of them, and pulled them apart. Been to the factory where the OMCs were made too - in fact I was there today.

The M3 cost about as much to produce actually, as did the Austen - the original Stens were cheaper, but really crude last-ditch weapons. None of these came anywhere near the OMC for reliability or durability, and Lysaghts was able to pump them out in good numbers for the right price.
Here's some figures:

In 1942 an Owen cost the Australian government 6 pounds (Australian), which equated to $16.80 US at the then-prevailing exchange rate. An M3 in 1942 cost the US government $15.00 a unit.

Not a big difference.
I seem to remember the figure of US$9.00 being quoted for the M3 when produced, where did you get your figures, daniel?

In any case, I stand corrected, whatever the difference was it wasn't that big compared to other inexpensive designs and they were all much cheaper than the wonderful -- I've fired one many times -- but heavy and frightfully expensive Thompson. But the Owen was a great gun, for sure.

By the factory, do you mean Lysaght's? What do they make now?

Several years ago, Small Arms Review had a very in-depth article concerning the various trials and tribulations Owen had to overcome in order to get his machine carbine accepted by the Australian military establishment. Each time the Army implemented a new obstacle to put Owen off, he simply overcame it and then exceded whatever requirements they made at the time. On several different occasions the Army changed the cartridge requirements, telling Owen one time the gun had to be in .32 ACP, then changing it to .45ACP, .38S&W, as well as 9mm. Each time, Owen made the necessary changes and made the prototypes work, though sometimes only being given a handful of live rounds to work with while making the adjustments. I believe that at some point, when it became so blatently obvious the Army was stalling (primarily because they had commited to making the Austen design work in spite of a number of problems with it), that certain political figures had to become involved, forcing the Army to adopt the Owen. Even then, after completing his government contracts, Owen was underpaid for his work, and on several occasions, the government was late in making their payments to his company.
The Sidewinder appears in articles from the late 70's thru the 80's.

Notes: The origins of this weapon are interesting. Delta was looking for weapons that would help them during Operation Eagle Claw, the abortive rescue of the hostages from the Iranian Embassy in 1980. One thing that Delta was looking for was a weapon that their operators could fire while roping down from helicopters (fast roping had not yet been developed). Two weapon designers, Sid McQueen and Donald Packingham, had been developing just such a weapon for some time, but the design proceeded slowly, primarily due lack of government interest – until the preparation for Eagle Claw began. Suddenly, Delta was very interested in the Sidewinder.

By 1980, S&S had four advanced Sidewinder prototypes (EX-002 in 9mm Parabellum, and EX-004 in 45 ACP). All were designed to be fired with one hand or two, were bullpup designs, and extremely well-balanced. The receiver and magazine could be rotated 180 degrees, without taking apart the weapon – one simply depressed a lever on the pistol grip while holding it vertically. (A later version, the EX-020 does not have this feature, for reasons which will become apparent in a moment.) This allowed it to be used by both right and left-handed shooters with equal ease, and could also allow shooters to shoot around left or right-hand corners quite easily. Construction was largely of a simple steel tube, with a steel barrel. The top of the receiver had a mount for a variety of collimator, laser aiming, or night vision sights. Fire selection was done by trigger depression – a short pull gave semiautomatic fire, while a full trigger pull gave automatic fire. The stock was simply a padded crescent-shaped steel piece – this was at the end of the main tube on EX-002 and EX-004, while on EX-003 and EX-020, a sliding stock and a shortened main tube were used. Caliber conversion was quite easy, consisting merely of changing the barrel, reversing the bolt, and changing the magazine. The magazine well had a projection which could be used as a speedloader for the magazines; the magazines used were Sten magazines for the 9mm Parabellum chambering, and M-3 Grease Gun magazines for the .45 ACP chambering. All but the EX-020 prototype were fed from the side of the receiver; EX-020 used traditional feed (from the underside of the receiver). The trigger guard swings downwards for use with heavy gloves. Fire controls are ambidextrous, as is the magazine release.

A peculiarity of all Sidewinders is the cocking knob. It is located at the center of the rear portion of the rear of the main tube, offset to one side. On all but the EX-020, the cocking knob reciprocates with the mechanism – which could lead to the knob hitting the shooter in the face if fired from the shoulder. As a result, S&S recommended that those versions should have the receiver rotated to the left if the shooter is right-handed and to the right if the shooter is left-handed. (The ejection port is far enough forward was to not present a problem in this regard. The EX-020 prototype has a non-reciprocating knob and therefore this is not a problem.

Though it is all very hush-hush, and to this day nothing official has come out, it is believed that Delta took two Sidewinders to Eagle Claw – the EX-003 prototype (an EX-002 with a caliber conversion capability, a Weaver sight base with backup iron sights, an extra fire selection setting (3-round burst), and a sliding stock); and the EX-005 prototype (an EX-004 with similar modifications except for the 3-round burst selector). Delta’s evaluations of the Sidewinder are still classified, but they apparently did not accept it for use after Eagle Claw. The EX-005 prototype in .45 ACP is identical to the EX-020 for game purposes; the EX-005 prototype in 9mm Parabellum is identical to the EX-020 prototype in 9mm except for the magazine it uses.

The final variation of the Sidewinder, the EX-020 prototype, did not appear until after Eagle Claw. Most of the differences are noted above, but it also had something the other prototypes did not have – a manual safety. The EX-020 also is much easier to field-strip and for armorers to work on, and in its 9mm iteration uses Uzi magazines instead of Sten magazines.

Unfortunately, no country’s military or police forces accepted the Sidewinder, and it became another footnote in history.

The SOF issue you want to find is Oct. 1979 pages 46-51. The article is "The Sidewinder revisited." by Chuck Taylor.
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