Complete Machine Instructions

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STEN Mk II SPECIFICA-TIONS
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1. Cartridge:
9mm Parabellum
Bullet weight
Powder
weight
Muzzle veiocity
‘116 grains
6 grains
1400 ft./set.
2. Recoil Spring:
Wire diameter 0.067 in,
Spring
OD
1.00 in.
Active coils
15
Free length
9.40 in.
Initial length 6.80 in.
Finai length
3.20 in.
Work stroke
3.60 in.
3. Bolt: Weight
(including extractor)
Cocking handle
1.327 ib. (9290 grains)
0.077 lb. (540 grains)
Total recoiling weight:
1.404
lb. (9830 grains)
Bolt maximum dia.
1.381 in.
Bolt overall dia.
5.75 in.
Bolt body length
4.21 in.
SUGGESTED STEN MANUFACTURING
NiODIFiCATIONS
Select suitable lightwall steel tubing which is
commercially available. For example, a -fence
post pipe (galvanized) is 38.5mm OD and
35.0mm ID, most suitable for use as a receive:.
Eliminate barrei sleeve.
Weld barrel bushing into the front end of the
receiver for simple, permanent assembly.
Turn barrel blank OD (outside diameter)
without any shoulder, fit the barrel in the
bushing by sliding fit.
Fasten the barrel
in the bushing by two roll
pins of
3/16” diameter, or equivalent.
Turn the bolt OD to fit the receiver ID.
The external portion of the cocking handle
(sticking out of the receiver) may be a straight
8.8mm OD, the same as the inside.
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The trigaer housing
against ‘birt
cover acts only as a guard
entering the trigger assembly.
This
ccJ<er
can be eliminated or made from
plastic.
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Ati pins can be roll pins of standard commer-
ciai size, or pieces of drill rod.
13. All springs can be of a standard commercial
size.
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11. Trigger material may be aluminum or plastic,
side
tabs may be replaced by spacers or
washers to keep the trigger located neutrally.
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l-7/4” diameter nominal size galvanized pipe,
schedule 40 is suitable for a modified receiver:
3D
ID::
42.2mm
35.05mm
YVaII thickness: 3.55mm
Ncte:
A 1” galvanized pipe fits loosely in-
side a l-1/4” pipe and can be welded
as a filler-spacer where needed,