Sten shooting high and right

[TommyT]

Hello I have just recently acquired a Sten MK2 Tube gun and ever since I got it I have always shot high and right of my point of aim and am wondering why. First off I have two barrels one that came with it and a threaded pike arms barrel and they both do the same thing so what I did was purchase a site lite sl-500 green laser bore sighter to see if the sights are off. What I noticed is this I point the gun 25 feet away and the laser is showing high and right but what is strange is that when I take the hand guard barrel sleeve off the laser is perfectly aligned with the sights perfectly center so I’m wondering why the gun is only high and right after I put the hand guard on ?

[StrangeRanger]

The sleeve is pushing the barrel out of alignment when it is tightened.

Since this happens with both barrels they are not the problem.  There is a problem with either the clamping face of sleeve or the front of the receiver not being square to the axis of the gun.  Since it's a tube gun,  I'm betting that the face of the receiver trunnion (or possibly the entire trunnion) is a skosh out of line.  Easy check: buy or borrow another sleeve and see if the problem goes away when you tighten the barrel with that sleeve,  If it doesn't it means a trip to the gunsmith to true things up

 

Edited August 11 by StrangeRanger

[huggytree]

Tap the front sight right 

Try a small shim under the barrel to tweak it down

ive had a smith put a blob of weld to pull a grease gun barrel slightly over. Worked.  
 

 

[TommyT]

Thanks for the replies I just looked at the sleeve and noticed the part that holds the barrel in place isn’t making full contact it might not be perfectly round so I ordered another one from gunbroker 

[TommyT]

Ok so what I did is purchase 2 more sleeves and it’s doing the same thing for all 3 sleeves i am aiming down the hallway without sleeve on it’s perfectly in line and when I put it on it’s fine until the last turn it’s the last turn that’s throwing it off

[StrangeRanger]

Well, there's 3 parts involved. The problem didn't go away when you swapped barrels and it didn't away when you swapped sleeves. that leaves the receiver. You need the services of a gunsmith to true up the barrel mounting 

Edited August 17 by StrangeRanger

[StrangeRanger]

There's a fair amount of bearing surface between the Sten receiver tube and the trunnion (barrel bushing in this diagram) which should make alignment more or less automatic but it is possible that the trunnion is not welded in true to the tube.  That would not be not an easy fix.  If you're lucky the interior shoulder on which the barrel ring rests is not square to the receiver.  With the right machinery that's a whole lot simpler to correct

Edited August 17 by StrangeRanger

[TommyT]

Well I went to a local gunsmith and it turns out all it was is the front sight just had to be drifted to the right. I’ll went to my local range and put the target back 25 yards and the laser boresighter is now perfectly straight the green dot is right on par with the front sight and when shooting it I was hitting directly in the middle where I was aiming. I didn’t know the front sight was driftable I thought it was welded in place.

[skoda]

It was designed and made to be movable but many were welded in place to keep them from moving.