Help zeroing my Sten

[5 Commando]

Yes sir. Note your remark on the ammo. I cannot easily source Mk2z so am going to work with what I can get.

Regarding eccentricity. Not sure if this is what you mean, but I ran a crude test on the barrel by rotating it in the trunnion and it appears to rotate evenly when sighting down the bore from above. By evenly I mean it didn't appear to the naked eye to deviate around the long. axis.

I do observe the following however: when fully seated, the base of the barrel appears to be visibly higher in the trunnion on the right side. This would - in my mind - support why it is hitting to the right. The vertical deviation I suspect is normal if the weapon is sighted in at 100 yds. Here a photo...

Attachment 81503

Could the problem be an eccentrically bored barrel? This was quite common and I had a chapped and machined Bren barrel showing the end elevation about 6" rear of the muzzle showing how eccentric it was. In armourers terms, we marked the BEST radial position of the barrel with regards to 'accuracy - such as it is - with a chisel mark at 12o'clock. The Sten barrel seating is soft soldered in position and rivetted. They did work loose but it was an easy fix.

Worth pointing out to you 5Commando that it's not a case of whether your Sten works and functions on commercial ammo. It may well do. But it cannot be zeroed using it. It was made to operate etc etc on UK Mk2z ammo. Try this