COMPONENT PARTS DIFFERENCES
Marks are determined by the tube casing, shown here stripped, even though designated on
the magazine housing. Note the difference in casing lengths forward of the trigger housing;
the Mk 2 {BE 9956) is shorter as the barrel protrudes further. Also note the safety slot on
the Mk 1 (BE 9955); on the lower side. The Mk III casing has a raised seam along the top.
Part numbers shown here can be referenced in the Parts & Vocab. section.
Butts are generally interchangeable on these Stens and a pistol-grip could replace the butt
(see page 36). The Butt, Mk 1 No.2 (BE 9958) was listed as being for the Mk 1 Sten; Mk I
No. 1 had a wood insert. Butt Mk II (BE 9952) was for the Marks II and III Carbines. The
Butt No. 3 (BE 8324) was modified to contain the Sten spike bayonet. Later wood butts
could also be fitted to earlier marks of Sten.
Trigger mechanism covers differ in the securing screw holes; the Mk 1 (BE 9951) and Mk 2
covers (BE 8383) are both likely to be found on the Mk II carbines while the Mk 2 cover was
designated for the Mk III Sten as well. The wooden furniture and folding handgrip were
originally on the Mk 1 gun while the folding grip had been dispensed with by the time of the
The rotating magazine housing (BE 9953) applied only to the Mk II gun as the Mks 1 and III
guns have the housing fixed to the casing. Mag catches differ in that the Mk 1 (BE 9070)
is complete with stud, but both Mks 1 and 2 (BE 8314) may be found on the three different
Marks of gun. Ejector (BE 9071) was for guns Mks 1 and 3 only while the ejector rivet (BE
8388) was for Mk III carbine only. The mag catch retainer (BE 9968) was for Mk II gun only.
The Mk 1 breech block (BE 9066) was for the Mk 1 gun while the Mk 1 * block (BE 9961)
fitted all three marks of gun. The Mk 1 block was fitted with the Mk 1 cocking handle (BE
9078) while the Mk 1* block has the Mk 2 handle (BE 9964). Extractors, pins, return
springs and end caps are interchangeable between all these marks of guns.
BL 0001
There are at least five different cocking handles for
the Sten breechblocks— Mk 1 (BE 9078), Mk II (BE
9964), Mk III (BE 8361), Mk IV (left) and Mk V (BL
0001). The Mk IV cocking handle drawing at left
features a push-in safety. This requires a 1 5/64-in.
hole drilled through the gun casing on the left hand
side, for the plunger to engage through for the safe
position. The Mk III and Mk V cocking handles were
Vocab. Nos. BE 8361 and Bl 0001 respectively.
The trigger mechanism is the same for the Mk 1, 1 *, II and III Sten machine carbines; the
triggers, springs, pins, levers and sears, mounting into similarly spaced and drilled trigger
housings. Magazines too are interchangeable as are the component parts within the
magazines themselves. The magazine platform had been advanced to Mk II but is
interchangeable.
The three 9mm barrels are different, however, between the Marks 1 & 1 *, Mark II and Mark
III guns. For the Mark III carbine, the barrel is fixed into the casing unlike the previous
Marks, so it is not listed as a separate component part, nor available for replacement at
lower workshop levels.
The Mk 1 barrel (BE 9065) has a reduced diameter at the muzzle to allow for the fitting of
the flash hider (BE 9073) which was complete with a forward sling swivel (BE 9097). The
flash hider, swivel and barrel were dispensed with on following guns. It was also fixed by a
screw (BE 8573). The Mk II barrel (BE 9960) has a collar or sleeve pinned (BE 8576) at the
breech end. The Mk II barrel was also fitted with a short, detachable, perforated sleeve (BE
9965) which incorporates the barrel nut, whereas the Mk 1 gun had a full length cover over
the barrel, a continuation of the tube casing from the breech.