The Sterling submachine gun is constructed entirely of steel and plastic and has a shoulder stock which folds underneath the weapon. Although of conventional blowback design firing from an open bolt, there are some unusual features: for example, the bolt has helical grooves cut into the surface to remove dirt and fouling from the inside of the receiver to increase reliability. The Sterling uses a much-improved (over the Sten) 34-round curved double-column feed box magazine which is inserted into the left side of the receiver. The magazine follower, which pushes the cartridges into the feed port, is equipped with rollers to reduce friction and the firing pin is designed so that it does not line up with the primer in the cartridge until the cartridge has entered the chamber.
The suppressed version of the Sterling (L34A1/Mk.5) was developed for covert operations. This version uses a ported barrel surrounded by a cylinder with expansion chambers to reduce the velocity of the bullet to prevent it from breaking the sound barrier and causing a sonic boom, along with decreasing muzzle blast and flash. This is so effective that the only sounds during firing are from the bolt reciprocating and the barely-audible explosive discharge.
The Sterling has a reputation for excellent reliability under adverse conditions and, allowing for the fact that it fires from an open bolt, good accuracy. While it has been reported that the weapon poses no problems for left-handed users to operate, it is not recommended without the wearing of ballistic eye protection. The path of the ejected cartridge cases is slightly down and backward, so mild burns can occasionally be incurred by left-handed shooters.
A bayonet of a similar design as that for the L1A1 SLR was produced and issued in British Army service, but was rarely employed except for ceremonial duties. Both bayonets were derived from the version issued with the Rifle No. 5 Mk I "Jungle Carbine", the main difference being a smaller ring on the SLR bayonet to fit the rifle's muzzle. When mounted, the Sterling bayonet was offset to the left of the weapon's vertical line which gave a more natural balance when used for bayonet-fighting.
For a right-handed shooter, the correct position for the left hand while firing is on the ventilated barrel-casing and not on the magazine, as the pressure from holding the magazine can increase the risk of stoppages, and a loose magazine can lead to dropping the weapon. The barrel-casing hold provides greater control of the weapon, so the right-hand can intermittently be used for other tasks. A semi-circular protrusion on the right hand side of the weapon, approximately two inches from the muzzzle, serves to prevent the supporting hand from moving too far forward and over the muzzle.
The primary user complaint with the Sterling series is that there are projections in all directions, and carrying it on a sling frequently results in the weapon catching on clothing, load-bearing equipment, foliage, and doorways/hatches, as well as annoying (sometimes painful) poking of the user.
| Sterling submachine gun | |
|---|---|
| Type | Submachine gun |
| Place of origin | United Kingdom |
| Service history | |
| Used by | |
| Wars | Operation Market Garden Suez crisis Aden Emergency Cold War Falklands War Northern Ireland Gulf War (final batch) |
| Production history | |
| Designed | 1944 |
| Specifications | |
| Weight | 2.7 kg (empty) |
| Length | 686 mm (481 mm folded stock) |
| Barrel length | 196 mm |
| | |
| Cartridge | 9x19mm Parabellum 7.62x51mm NATO (Battle Rifle variant) |
| Action | Blowback Lever-delayed blowback (Battle Rifle variant) |
| Rate of fire | 550 round/min |
| Effective range | 200m (50-100m suppressed) |
| Feed system | 34 round box magazine 30 round L4 BREN magazine (Battle Rifle variant) |
Sterling Variants
- British Army
- Unassigned: Patchett Machine Carbine Mark 1 (trials commenced in 1944)
- Unassigned: Patchett Machine Carbine Mark 1 & Folding Bayonet (same as above but with folding bayonet, never accepted)
- L2A1: (Patchett Machine Carbine Mark 2) Adopted in 1953.
- L2A2: (Sterling Mark 3) Adopted in 1955.
- L2A3: (Sterling Mark 4) Adopted in 1956. Last regular version in service with the British Army.
- L34A1: Suppressed version (Sterling-Patchett Mark 5). Held in reserve by the British Army.
- Sterling Mark 6 "Police": a semi-automatic-only closed-bolt version for police forces and private sales. A US export version had a longer barrel (16 inches) to comply with BATF regulations. Beginning in 2009, Century Arms International (CAI) began marketing a similar semi-auto only carbine manufactured by Wiselite Arms. These too have a 16" barrel. They are assembled using a mix of newly-made US parts, and parts from demilitarized Sterling Mark 4 parts kits. This is often marketed as the "Sterling Sporter".
- Sterling Mark 7 "Para-pistol": Special machine pistol variant issued to commando and plainclothes intelligence units. It had a shortened 4" / 108mm barrel, fixed vertical foregrip, and weighed 4.84 lbs. / 2.2 kg. If used with a short 10- or 15-round magazine, it could be stowed in a special holster. It also could be used as a Close Quarters Battle weapon with the addition of an optional solid stock.
- Canadian Army
- C1 Submachine Gun: Adopted in 1958, replacing the STEN gun in general service. It is different from the British L2 in that it made extensive use of stamped metal rather the more expensive castings used by British production SMGs. It also had a removable trigger guard (for use with gloves in Arctic operations) as a standard option and used a new 30-round magazine.
- Indian Army
- SAF Carbine 1A: Indian made Sterling L2A1.
- SAF Carbine 2A1: Sterling Mark V silenced carbine.
7.62 NATO Variant
A variant of the Sterling submachine gun was manufactured in the 7.62x51mm NATO calibre. It used lever-delayed blowback to handle the more powerful rounds and was fed from 30 round Bren magazines. A bipod and detatchable fixed stock could be added as well as a Single Point IR/Trilux nightsight. To prevent ammunition cookoff, the weapon fired from an open bolt. Acting as the Besal LMG of World War II, the 7.62 NATO calibre Sterling was intended as an emergency standby weapon in case of attack during the Cold War.
