The Sten Gun
The Sten machine carbine was a 9mm select fire submachine gun. It was developed during the war in response to the need for an easily manufactured weapon that could provide sections with greater firepower.

Based on a lengthy trials period the pre-war army had intended to adopt the Lanchester submachine gun, a hardy design copied from early German weapons. War broke out before the Lanchester could be produced in quantity, and the government began purchasing Thompson sub machine guns from the United States. While the Thompson proved popular with troops in North Africa and Italy, it was expensive to manufacture. Tactical experience was also showing that there was a much greater need for section-level automatics than previously thought, and so the government looked for a home-grown alternative to the Thompson.

Mk II Sten
Mk II Sten

Mk V Sten
Mk V Sten

The Sten was the result. It a very simple weapon, using an open-bolt blowback system. It has a selector switch to fire either semi-auto or full-auto. It was very cheap to produce, simple to operate, and could be quickly dismantled. The troops who used it often considered it a liability, however, as it was prone to jamming if not properly maintained. This was compounded by poorly-made magazines which caused feed problems. (Click on the images to see full-size version.)


Mk II Trigger Housing
Mk V Trigger Housing

The Sten had several models, including silenced versions for commandos and partisans. By far the most common type of Sten was the Mk II. Late in the war the Mk V was developed for airborne troops. While there are a few internal changes in the trigger housing between the Mk II and the Mk V, the biggest change was the physical appearance. A wood buttstock, pistol grip, and fore-grip were added. The barrel was also milled down and fitted with the shielded fore-sight from the Enfield rifle. This modified barrel could also fit the spike bayonet. (Click on the images to see full-size version.)

Mk II Breech
Mk V Barrel



Small Arms Training
This manual belonging to a unit member is dated August, 1942. The cover is pictured to the right. It is approximately 7" tall and 5" wide, 12 pages long. It contains information dealing with all aspects of using the sten carbine, including safety, parts, loading/unloading, firing, cleaning, and attaching a spotlight.

Following are several quotes and pictures from the text describing the proper usage of the STEN.

Then weapon is especially useful when on patrol or for fighting in close country such as woods and villages. Under these conditions the enemy may appear at close ranges and from different directions, and by firing from the waist such targets can be instantly engaged. Where time permits the weapon will be fired from the shoulder.

It is an automatic weapon, operated by the recoil of the spent case acting on the face of the breech block.

The machine carbine will fire bursts or single shots, and it will fire most makes of 9mm ammunition, including German and Italian.

If the working parts are forward [the bolt forward closing off the breech] with a full or partially full magazine in the magazine housing, a smart jerk may cause a round to be fired. On no account, therefore, will the machine carbine be carried, or allowed to remain, in this condition.

Holding at the waist. -- The left foot is advanced with the knee bent, the weight of the body being balanced on the left foot. The right hand is on the butt with the forefinger on the trigger, the left hand on the barrel locking nut with the wrist under the magazine, the butt of the weapon is pressed tightly against the side by the right arm. The left elbow is pulled well back into the body in order that, no matter in which direction the firer turns, the weapon is brought automatically in the same direction. Care must be taken that the little finger of the left hand is clear of the ejecting opening.

The machine carbine can be carried in any convenient position, but when expecting to meet the enemy it should be held at the waist. From this position it can be instantly cocked and fired, or, time permitting, it will be fired from the shoulder.

Having disposed of the target the weapon will be placed at safety by placing the cocking handle into the safety slot. If necessary change the magazine.




Illustrated Identification List
This manual belonging to a unit member is dated August, 1942. The cover is the picture to the right. It is approximately 5" tall and 7" wide, 22 pages long. It contains pictures of all the parts for the STEN carbines; Mk. I, II, and III. Each picture shows sizes for the parts, along with referenced parts numbers, descriptions, and a remarks section.

Below are pictures from the manual showing the different marks and their parts. Click on any picture to view a larger version. At the bottom of the page are several good links for information on the sten.


The STEN Mk.I
The STEN Mk.II

The STEN Mk.III
Bolt Assembly

Bolt and Trigger Housing
Barrel and Magazine Housing



Related Links
  • An excellent history and description of the STEN can also be found at Canuck.