The submachine gun was developed as early as World War 1 but was not featured prominently in the battles of the industrial world until World War 2 when the British STEN, American M1 "Thompson, Italian Beretta M38, German MP38 and Soviet PPSh-41 all made their mark. For the British, the cheap-yet-effective STEN proved a material hero, hurriedly pushed through development due to the desperate need of the period and pressed into service during 1941 - upwards of 4.6 million were produced according to sources and dozens of global users could attest to its simplicity and robustness. The weapon was chambered for the 9x19mm Parabellum German pistol round and fired through a blowback action using an open bolt. The type was clearly identified by its side-mounted 32-round straight magazine and crude metal stock.
With Allied forces firmly entrenched in the fighting of World War 2 by 1944, British authorities moved on a new submachine initiative. The type would retain the STEN's 9mm chambering and be of similar compact form while providing enough weight to serve as an accurate platform between the required short and medium engagement ranges. A submission from the Sterling Armaments Company at Dagenham - attributed to George William Patchett, its chief designer, and recognized as the "Patchett Machine Carbine" - drew the attention of British authorities who ordered it for evaluation. It eventually came to be known under its more recognized generic name of "Sterling Submachine Gun" though, officially, it was listed in British nomenclature as the "Patchett Machine Carbine Mark 1".
Despite a broad resemblance to the earlier STEN, the Sterling was its own design. It utilized a tubular body containing the action and feed as well as iron sights (rear flip with front adjustable). The barrel was shrouded by a perforated sleeve to assist in heat dissipation while also serving as a heat shield for the forward hand. A curved box magazine was inserted into a left-hand port along the middle of the receiver. There was an angled pistol grip with ringed trigger unit under the design, also close to center. The rear was capped by a folding skeletal metal butt which was hinged along its two connecting arms to fold under the receiver for a more compact travel form. The weapon fed from a 34-round magazine and fired 550 rounds-per-minute out to an effective range of 220 yards. The action was of blowback as in the STEN and construction was primarily of steel with some plastic. Despite the obvious use of the magazine as a hold point for the forward hand, it was suggested that the operator hold the weapon along the barrel shroud to decrease the chance of stoppages by putting unnecessary pressure on the magazine and, therefore, potentially disrupting feed mechanism.
With design and development completed, early batch forms were issued to some specialist units who could make good use of the new compact firearm. British airborne elements in Arnhem became some of the more notable early operators of the Sterling and proved its effectiveness in the bloody fighting that followed during the "Bridge Too Far" campaign - General Montgomery's master plan to bring the war to a close by Christmas 1944.
In practice, Sterlings gave a good battlefield account of themselves which solidified their place in the post-war market. Despite the entrenched status of the fabled STEN, the Sterling was adopted as its replacement beginning in 1951 under the post-war designation of "Submachine Gun L2A1" (previously known as the "Patchett Machine Carbine Mark 2"). The Sterling Mark 3 became the L2A2 of 1955 and the Sterling Mark 4 became the L2A3 of 1956 - this becoming the final Sterling production form adopted by the British Army. The L34A1 was a specialized suppressed variant with a completely enclosed barrel and muzzle to dampen the exiting bullet noise (identified plainly as an audible "crack"). Indeed, it is said that only the sound of the moving bolt was made during the firing action of a suppressed L34A1, such was the efficiency of the integrated suppressor. The L34A1 was issued to special forces commandos and proved useful in clandestine operations where compactness and silence were key qualities. Another variant, the semi-automatic-only Sterling Mark 6 - was issued primarily to police forces. The Sterling Mark 7 was a shortened variant for improved portability with issue to special military units.
Like the STEN before it, the Sterling proved a popular submachine gun design all over the world. Operators included Argentina, Canada (as the C1), India (as the SAF Carbine 1A/2A1), Kenya, Lebanon, Libya, Malaysia, New Zealand, Nigeria, Pakistan, Philippines, Portugal, Singapore, Spain and Zimbabwe (among others; see variants section below for complete list). India still manufactures the Sterling (conventional and suppressed forms) through its Indian Ordnance Factory. Chile produced Sterlings at one time through its FAMAE brand while the Royal Ordnance Factory (Fazakerley) produced Sterlings solely for use by the British Army due to exacting requirements. Local Canadian Sterlings were produced through the Canadian Arsenals Limited brand label.
When NATO formally adopted the 7.62x51mm NATO cartridge as its standard rifle cartridge, gun firms moved in response and the Sterling was one such product that was converted to fire it. This 7.62mm variant saw its internals reworked to utilize a lever-delayed blowback method of operation as the new cartridge itself was of a greater charge than the smaller 9mm Parabellum pistol rounds used previously. Of course the change in caliber necessitated a change in magazine structure as well so 7.62mm Sterlings were issued with the 30-round BREN Light Machine Gun-style detachable box magazine over the original 32-round curved/STEN submachine gun versions.
The L2A3 variant saw service into 1990 until formally replaced by the new L85A1 5.56mm assault rifle with British forces. During its tenure, the L2 provided good service for the British Army where it became a reliable weapon even under the most difficult of operating conditions. Much of this was owed to its rather basic, no-frills design approach and solid construction which, the latter making it more expensive than its contemporaries, allowed the weapon such a lengthy service life.
The L2A3 exhibited a length (butt extended) of 27 inches and could collapse into a more handy 19 inch form with the butt folded. Weight was approximately 2.7 kilograms and the barrel measured 7.75 inches long. Muzzle velocity was rated at 1,250 feet per second.
The suppressed L34A1 sported a length of 34 inches and collapsed into a 26 inch form. Weight was 3.6 kilograms with a barrel length of 7.8 inches. While still holding a 550 rounds per minute rate of fire, the weapon managed a lower muzzle velocity of 970 feet per second. The L34A1 received its share of notoriety during the Sterling's operational service life - it was put to good use by Australian and New Zealand special forces during the Vietnam War (1955-1975) and was used - ironically enough - by both sides of the Falklands War (1982) conflict - Argentina and Britain.
In all, some 400,000 Sterlings were produced. In popular culture, Star Wars fans will note that it was the Sterling submachine gun that made up the base form of the Stormtrooper laser blaster. The similarities are apparent to the trained eye considering the blaster's general shape, length and mid-set pistol grip and trigger unit.