Benelli M4 Collapsible stock receiver extension orientation/keying question

[bambihunter]

I've got 2 Benelli M4's. An original 11711 H20, and one I bought used from a former co-worker that was built up with 922r components, then added collapsible stock and extended magazine. The collapsible stock settings on the H20 are smooth as butter. But, on the black M4, it takes some considerable wiggling to get it lined up. Also, it likes to lock in at a canted sideways position off to the side in a position or two. Would one of you installer experts take a look at these and tell me first is this a Benelli receiver extension or did he get some generic aftermarket unit. Second, is it installed and keyed in the correct orientation, i.e. rotated into the correct position for it to function properly. If so, any suggestions? I previously had it more oily then in the pictures seeing if that would help, but the glare made it harder to photograph so I wiped much of it off.

I just realized I didn't take any pictures with the stock on it. It does sit at proper angle it appears in the all the way in and all the way out positions. I can't seem to hit the middle one. I can take pics if of it too if that helps.

[RxArms]

Looks like OEM to me.  Quite possible the recoil tube wasn’t installed properly aligned on the reciever.  Some collapsible stocks have different tolerances than others.  Have you tried your H2O stock on your black gun and vice versa?

[StrangerDanger]

The receiver extension was installed wrong. Those notches on the extension should be facing top dead center. From the photos it appears to be canted about 10-15 degrees to the right. 
 

The extension will need to be removed with heat assuming they applied thread locker to the components, chemically cleaned and retimed correctly. 
 

You’re also missing a snap ring in the end of the extension. *Edit, never mind, I see it in one of the photos above.

*When the extension is being instead, it has a tendency to turn when tightening the jam nut. Happens to me all the time during my installs. You have to apply counter torque to the extension with a 19mm wrench on the flats while tightening the jam nut. If you aren’t checking the work with a collapsible stock afterwards, this alignment issue can present itself. 

Edited July 12, 2022 by StrangerDanger

[RxArms]

3 hours ago, StrangerDanger said:

The receiver extension was installed wrong. Those notches on the extension should be facing top dead center. From the photos it appears to be canted about 10-15 degrees to the right. 
 

The extension will need to be removed with heat assuming they applied thread locker to the components, chemically cleaned and retimed correctly. 
 

You’re also missing a snap ring in the end of the extension. *Edit, never mind, I see it in one of the photos above.

*When the extension is being instead, it has a tendency to turn when tightening the jam nut. Happens to me all the time during my installs. You have to apply counter torque to the extension with a 19mm wrench on the flats while tightening the jam nut. If you aren’t checking the work with a collapsible stock afterwards, this alignment issue can present itself. 

I don’t notice the same thing with notches and dead center.  For me, the top notches are a bit off center when the buttstock is centered.

[StrangerDanger]

2 hours ago, RxArms said:

I don’t notice the same thing with notches and dead center.  For me, the top notches are a bit off center when the buttstock is centered.

You're right. I never noticed that it was canted to one side.

 

I'd probably experiment with the two stocks. See if both stocks behave the same way on the black M4. If so, that means the issue is with the extension. If the issue is only present on the black M4's stock, then we can try to sort out which part is out of spec.

[bambihunter]

Great idea. I'll check that suggestion in the next day or two and report back. I don't know why it didn't occur to me to remove the stock from the 11711 and look at how it is oriented.

Thanks guys. ?