Building the Canadian Semi-Auto STEN

[Claven2]

Now we'll look at building a 18.5" non-restricted barrel with dummy suppressor for the non-restricted Sten we're building on the British Sten MkII kit.

We start with a spare 9mm barrel blank we had lying about. There is some old corrosion on the outside of the blank, but the bore is perfect, and once the tube is bead blasted, parkerized and covered by the dummy suppressor, the cosmetic blemished won't be a factor.

Here we have the barrel retained by a barrel nut that will form the base of the suppressor. The suppressor will thread onto the Sten receiver in place of the ventilated MkII barrel nut/handguard. The serrations on the base of the barrel nut will be done later with a cold chisel.

For scale, note the muzzle bushing at the top:

And here we have the assembly minus the dummy suppressor tube. This suppressor is being built to copy the longer SOE Version of the MkIIS, not the standard tube which is much shorter.

The barrel is threaded into the sleeve that provides the shoulder for the barrel nut, as the original barrel outer diameter was too small to create a shoulder in the lathe. We used 3/4-16 threads, external ones cut with a lathe, internals with a tap. The threads on the collar are lathe cut.

The barrel has been torqued into the sleeve quite tight so we may not install a transverse retaining pin - there would be no way to access a pin without a hole in the barrel casing (dummy suppressor), and its not needed to secure the threaded joint.

To remove the barrel nut from a standard Sten barrel, you would use a punch through one of the rearmost holes.

The body of the suppressor is just made with appropriate diameter steel tubing.