The Simplistic British Sten Machinegun

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The British Sten gun was designed from the outset to be simple to produce in austere spaces. At a time when the British were pressed on all sides, Major Reginald V. Shepherd and Harold J. Turpin contrived a weapon that could be thrown together in bicycle shops and automotive garages by the millions. In so doing, Shepherd and Turpin unintentionally created the ultimate American recreational machinegun. It was the Sten’s innate simplicity that made it so amenable to civilian consumption on this side of the pond.

The quirky world of American machinegun collecting is unique on Planet Earth. There are surprisingly large numbers of folks who are into it, but the astronomical sums involved leave many potential enthusiasts on the sidelines. All that arose due to two unfortunate pieces of legislation.

The National Firearms Act of 1934 set out to tax private ownership of machineguns out of existence. The inaptly-titled 1986 Firearms Owners’ Protection Act actually outlawed production of automatic weapons for sale to civilians. The cumulative result was to cap the number of transferable machineguns at around 180,000. Each year, more young Americans come of age and covet a stuttergun of their own. With the pool of guns irrevocably fixed, that causes prices to soar astronomically. Residing right in the middle of that sordid milieu is the humble British Sten gun.

Origin Story

In the desperate months following the evacuation at Dunkirk, England bought all of the American Thompson submachine guns that they could get. However, the M1928A1 Thompson cost $200 in 1939. That’s about $4,500 today. The Brits also had to run the gauntlet of German U-boats to get these guns to the war. Our allies desperately needed something cheaper they could build at home.

The Thompson was meticulously machined out of big blocks of forged steel. By contrast, the Sten was utilitarian in the extreme. The receiver was little more than a length of muffler pipe. The bolt, trunnion, and barrel took a little machine work, but most everything else was formed from steel pressings. When British industry finally found its stride, they could produce Sten submachine guns for $11 apiece. That’s about $130 today.

Details

The Sten went through seven production versions along with several experimental subtypes. The Mk III, with its welded magazine well, was the cheapest and most austere. It is arguably the rarest variant in American civilian hands, because of the way the receiver is formed. Roughly half of the total production run was the Mk II. The Mk V was a similar gun that sported fenced sights along with wooden furniture. The sound-suppressed Mk II(S) and Mk VI versions were lightyears ahead of their time. All Stens operated around a common chassis.

The Mk V is the most refined of the various marks. Curiously, the receivers of the Mk II and the Mk V are not interchangeable. The basic tube is the same, but the relief cuts are made in different places. The fire control unit on the Mk V rests 1.3 inches farther forward than that of the Mk II. All these issues are surmountable, but it takes a little engineering to do so. I found that out myself when I built a Mk V out of a virgin transferable Wilson Arms 
Mk II tube.

The Sten gun hits way above its weight, particularly when compared to more expensive weapons like the American Thompson and the German MP40. It is crude and ugly, but the comatose 550 rpm rate of fire makes burst control easy. That makes the Sten the perfect civilian starter MG.

Modern Treatment

Transferable machineguns in America come in two broad flavors. Most transferable Stens were produced by American gunsmiths prior to 1986 using demilled wartime parts kits and seamless muffler pipe. With more than four million militarily superfluous Sten guns floating around international arms markets, demilled parts kits have always been relatively cheap. I bought several for $60 apiece some fifteen or so years ago. The same attributes that made the gun easy to produce in wartime made it easy to produce by gunsmith hobbyists on this side of the pond. Prior to the 1986 ban, small American gun manufacturers registered Sten tubes by 
the thousands.

The BATF insisted that a certain amount of machine work be done prior to the 1986 cutoff to allow these tubes into the registry. You couldn’t just serialize a piece of 1.5-inch drawn-over-mandrel tubing and call it good. Lots of 07/Class 2 shops made these things. A partial list includes: CATCO, DLO Mfg., Charles Erb, FAKTS, Fleming Firearms, Interport, John Stemple, Pearl Mfg., Qualified Mfg., S&H Arms, Silver Bullet (York), Specialty Weapons, Taylor Manufacturing, Wilson Arms, and York Arms. Stens (as well as other models like the Sterling SMG), when manufactured with tube steel and parts kits, by US gun firms, are known as “tube guns.”

There are those who might split hairs over the quality of production, but that really doesn’t much matter in this case. The Sten was an intentionally forgiving design. If somebody did a poor job assembling one of these guns, it doesn’t take a great deal of talent to strip the tube down and redo it. So long as the slots are pretty close and you have a magazine it likes, the gun should run.

A smaller subset of the population is comprised of original WWII-vintage guns most commonly brought home by GIs serving overseas back when that was legal, but only if there was no magazine, or other major part which facilitated full-auto fire (like the bolt), present with the gun. However, these “bring backs” would have had to be registered under the one-time amnesty program in 1968. Original guns are classified as C&R, short for curio and relic. The BATF defines C&R guns as original firearms over fifty years old. As a result, each year a new crop of legacy weapons is added to the C&R list. Such a designation means that you can transfer these weapons via a C&R FFL.

Every firearms enthusiast needs a C&R FFL. They cost ten bucks a year, and the application process is no more onerous than that required to buy a sound suppressor. You can then have old C&R guns shipped straight to your door. In the case of transferable machineguns, all of the NFA (National Firearms Act) rules still apply. However, if buying a gun from an individual in another state, having a C&R FFL means you avoid one of the two stupid $200 transfer taxes.

Prior to the 1986 ban, a transferable Sten cost about $150 in the mid 1980s. That would be about $440 in today’s money. According to Machinegun
PriceGuide.com, these guns were selling for around $3,000 in 2004. In the first quarter of 2024, transferable Sten “tube guns” were running between $9,000 and $12,000. Original C&R guns, which had to be imported before the 1968 Gun Control Act, were closer to $18,000. All transferable machineguns are expensive, but the Sten is, believe it or not, cheaper than most.

Another curious angle on the Sten saga is the Stenling. Stenlings are Sterling submachineguns built up on transferable Sten tubes. As the overall geometry is almost but not quite the same, the BATF has blessed this enterprise so long as the receiver slots aren’t molested. Building a Sterling out of a Sten tube takes some serious talent. The conversion involves a fair amount of silver soldering to affix the Sterling parts to the host receiver. From the user’s perspective, so long as the conversion is done well and the appropriate crinkle finish applied, Stenlings are essentially indistinguishable from the originals.

Despite being crude, ugly, desperate, and awkward, the Sten gun was nonetheless still an exceptionally cost-effective close combat tool. The same attributes that helped the Sten save Great Britain during WWII make it a desirable NFA investment today. 

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