Jump to content

Sten arrived, but won't run. Sear lever ?


Recommended Posts

Picked up my Sten MkII Neal Smith tube gun today and couldn't wait to get to the range.

Then came the "Buzz Kill"...

In Full Auto position it fires only Semi, and in Semi it won't fire at all.

:-(

A little poking around and I can see the Sear Lever just barely touches the bolt when in the FA position. Just enough that when manually cycled it appears to work, but under the violent recoil of live fire that light touch is enough to reset the trigger. I the semi-auto position the sear lever is held down just enough to cause the notch in the sear lever to slip off the sear without moving the sear to release the bolt.

I found drawings showing the leg on the sear at 26mm(1.023 in). Mine is 1.035 inches, or about 1/4mm longer than the drawing(looks new, likely a recent replacement). I think the pin holes are also pretty loose looking, and being a tube gun, it may be out of spec in several demensions which collectively add up to "it don't run".

So my question is, anyone ever have to "adjust" a sear lever on a Sten?

Anything else I should try before filing down the sear lever?

Thanks

Ray

Link to comment
Share on other sites

This is from memory....For full auto, doesn't the selector switch push the trip to the side? So the bolt does not hit the trip at all? And when selector set to semi, the trip swings back under bolt, to trip at each cycle of bolt.

Sounds like something is out of alignment, bent or just not assembled correctly.

Link to comment
Share on other sites

There is a step on the bottom of the bolt that is only on one side. In semi position the lever is hit by this step, causing the trigger/sear to reset. In full auto position the lever is moved to the side without the step so that the trigger/sear does not reset.

Because the lever is too tall, it hits the bottom of the bolt even when on the side without the step.

When on the side with the step it hits the bottom of the bolt even more, preventing the lever from engaging the sear.

 

I'm pretty sure that taking about 0.020in. off the height of sear lever will solve both issues. It is a cheap part($5 ea), so I will try that first. I ordered some spares today.

-Ray

Link to comment
Share on other sites

Took .020 in. off the sear lever and everything seems to work perfect through two mags.

I'll try more testing when I can get more range time.

-Ray

Link to comment
Share on other sites

  • 4 months later...

Same thing happened to me..many moons ago...first trip to the range instilled the notion you had better be prepared to fix most MGs at sometime or another.I remember taking a York tube MKII apart several times to "gently file" the sear lever....only to have a buddy grab it and grind it on the cement floor of the range....worked beautiful ever since :happy:

Link to comment
Share on other sites

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now
 Share

×
×
  • Create New...