The Sterling Submachine Gun – Magazine

In May 1946, George Patchett patented a new curved magazine which would become one of the Sterling’s most recognisable features. It addressed some of the serious shortcomings of the STEN’s magazine.

George Patchett’s machine carbine, Which later that came to be known as the Sterling, had been initially designed to use the standard STEN magazine. This makes complete sense as not only was the STEN’s magazine readily available but it stood to reason that the British Army would prefer to retain the large number of magazines it already had in stores.

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A Sterling L2A3 with a disassembled Sterling commercial-pattern magazine (Matthew Moss)

The STEN’s magazine is, however, the gun’s weakest link. Its a double-stack, single feed 32-round magazine was difficult to load and could feed unreliably when not looked after. The Patchett prototype performed well during initial testing in 1943, but later sand, mud and arctic testing of the Patchett against various other submachine guns highlighted the limitations of the STEN magazine – regardless of the weapon using it.

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Patchett’s Original Toolroom prototype (Matthew Moss)

At some point in 1945, Patchett developed a series of new magazines, a 20-round ‘Patrol’ magazine, a 40-round ‘Standard’ magazine and a 60-round ‘Assault’ magazine. By late 1946, these had been superseded by a 35-round magazine designed to fit into the basic pouch of the British Army’s 1944 Pattern web equipment.

Patchett addressed the STEN magazine’s shortcomings by designing his magazine with a curve which allowed the slightly tapered 9×19mm rounds to feed more reliably. He also replaced the traditional magazine follower with a pair of rollers which minimised friction and allowed dust, grit and dirt to be rolled out of the way improving reliability. Patchett’s magazine was designed so it could be economically stamped from sheet metal and folded and spot welded into shape. It was also simple to disassemble for cleaning and requires no tools for disassembly.

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George Patchett’s US patent for his roller magazine follower (US Patent Office)

By 1951 the magazine had been largely perfected but a trials report suggested that the magazine’s feed lips needed to be reinforced. Despite this the Sterling was said to be “better than all other weapons tested.” Following further development and testing the L2A1 Sterling submachine gun was eventually adopted in the summer of 1954. We will cover the development, adoption and service of the Sterling at a later date.

In 1952, Patchett added a pair of strengthening ribs to the inside of the magazine which also further reduced friction on the rollers. He also replaced the oval follower spring with a more efficient circular one with the ribs acting to hold it in place. The final production magazines held 34 rounds and were substantially easier to load than the earlier STEN’s.

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Patchett’s US patent for his circular magazine spring held in position by the stamped magazine body (US Patent Office)

The L2A1/MkII, introduced in 1954, was the first Patchett to incorporate an angled magazine housing which improved feeding reliability from the Patchett’s patented curved, double stack, double feed magazine. The Sterling’s magazine housing was angled forward slightly at 82-degrees.

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Diagrams showing an L1A2 magazine (British Army Manual)

The magazines used by the British military differed from Patchett’s design. The British government, perhaps unwilling to purchase the rights to manufacture Patchett’s design, developed the ‘Magazine, L1A2’. Nearly two million of these were built at Mettoy, Rolls Razor, ROF Fazakerley and the Woolwich Royal Laboratories. The L1A2 magazine was slightly simpler to manufacture but retained Patchett’s roller follower while the magazine’s body was made from two, rather than four, pieces of stamped steel and electrically welded together. The government-designed magazine is 5cm (2 inches) longer than Sterling’s magazines.

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disassembled Sterling commercial-pattern magazine (Matthew Moss)
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Rear edge of the magazine, with Sterling factory markings (Matthew Moss)

The example magazine seen above and in the accompanying video is Sterling-made and is marked with the company name and patent numbers. We can see the folded sheet metal construction and the overlaps at the rear of the magazine body.

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Patchett’s patented-roller follower and circular amazing spring (Matthew Moss)

When Canada adopted the C1, a modified version of the Sterling, they dispensed with Patchett’s roller system and designed their own magazine which held 30, rather than 34 rounds, but could be used in all Sterling-pattern guns.

On the front of the magazine is an over-insertion stop built into the edge of the magazine body, at the rear is another magazine stop with a flat spring which limits rattle and helps properly align the magazine in the breech for optimal feeding.

With out patented swiss pointing device we can see the base of the magazine catch which interfaces with the magazine. The magazine release button is wide and quite ergonomic. We can see from this angle how the magazine housing is angled forward.

Bibliography:

The Sterling Submachine Gun, Matthew Moss (2018)
[Copies of the book are available here]


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