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M11/9 Troubleshooting / Project Page

A few words: This page has been written to help the owners of legal, registered machineguns- this information is not to be used for the illegal conversion, or manufacture of machineguns.  I assume no responsibility for your injuries.
On a less legalistic note - I may redefine the internals of this gun, if I have, I have tried to document what I am talking about with labelled photos, please refrain from trashing me on the boards, as I am not a misinformed idiot, I just like using my own terminology (as a Chemist - I get sick of learning the jargon).  I hope this helps some people!!



My M11 will only shoot SA, or bursts on FA-- what's the deal?

You wait 3+ months, pay the bloody feds 200$, and get a gun that acts like your AR 15 when it needs a new trigger.  Frustrating as hell.  What could be the problem?  Before you can solve a problem, you must first understand whats going on - below is a picture of the internals of my M11/9 (well worn).

The sear (large part that is to the left of the word sear) holds the bolt open (holding occurs at the point below "ec" of the word disconnector), when the trigger is pulled, it acts on the disconnector (in the image its the part that is beneath the "on" of disconnector)- the disconnector pulls on the sear, and the bolt slams forward stripping a round from the mag., chambering it, and firing it.  This process continues in FA mode.  In SA mode, the trip (piece beneath "T" of the word trip) strikes the bottom of the bolt, and pivots, acting upon the disconnector - which disengages from the sear, so the sear again "catches" the bolt.
    Now the problem you are encountering is due to the disconnector disengaging from the sear when its not supposed to, and this can be due to:

Weak/malformed trigger spring - the disconnector is not being held in a position that positively engages the sear - FIX by buying a new trigger spring (buy a few at a time... they are cheap-ish)

Trigger/disconnector roll pin is worn: FIX - ACE hardware, 7c / ea buy a few.

Trigger "Y" where disconnector sits has spread - this causes the disconnector to be wobbly:  FIX - Vise grips, bend it a little bit at a time till the disconnector doesn't wobble side to side (must still move front to rear to maintain function)

Sear notch that no longer engages the disconnector: FIX - Buy a new sear, once the problem is fixed, the sear shouldn't wear at this surface as much - like anyone spends a lot of time shooting a bullet hose in SA!!



I think that covers it! If you know of another reason that this occurs, please let me know.


I pulled the trigger, and the gun didn't stop after I released it - WTF?

If the sear is worn (pic. below), or the notch in the bolt where the sear engages is worn (above pic), then the bolt will not be reliably "caught" by the sear when you remove your finger from the trigger.  This situation can be dangerous, especially in the hands of a less experienced shooter.
FIX- Buy a new bolt if its worn, or a new sear - or both.  You could attempt to sharpen, or reform the notches with a file/dremel/mill, if you are a cheap bastard - as I am, you'll try that first.

Another cause of this problem is underpowered ammunition, if the bolt fails to move far enough to the rear to engage the sear, but far enough to strip another round from the magazine, the gun will fire continuously - till it jams, or runs out of "fodder."  It seems that this situation would occur infrequently, as loading a round that meets the parameters for this malfunction seems unlikely.


This f-ing gun keeps jamming - what wrong with this ugly P.O.S?

Most likely problem is the use of the zytel mags.  As these "self lubricating" mags are used, they wear - zytel is softer than brass, and over time, the feed lips get eaten away.

The lips also spread as the mags are loaded over and over... and over and over see pic above).  FIX:  Disassemble mags. Take a pair of vise grips (many of my home gunsmithing projects involve vise grips) and adjust them so they are snug around the flat base of the mag. lips (pic below) - then take them off, and tighten them 1/4 - 1/3 turn - place them in boiling water for 5 minutes.  Let them cool (freezer) - and check the seating angle.  Once done - make sure the mags are clean, and a friend recommends dry lubing with molybdenum disulfide, or graphite.

 It is also possible that the mag has split down the rear seam - if it has, you are out of luck, I have no idea how to fix that - if you find a way, please let me know, I have 2 dead mags.

As a response to the above comment, THE NIGHTHAWK responds:

I read your page of M-11 malfunctions. I also had a M-11 mag split on
me. This one was a M11-380, same size just that the lips are a little

I fixed it by using the strongest two part epoxy, and glued it

I learned after attempting to do it three times that it is important
that you sand the inside of the split using a fine wet/dry sand paper
like 330 to 600 grit. Then using a cotton swab clean the area real good
with alcohol. Wipe it dry, the secret is cleaning it well,  because the
zytel has oil in it, and you have to get as much of that out as
possible. Then mix your two part epoxy real well, then using a tooth
pick apply it to the inside of the seam on both sides, work it in. Then
apply a coating on the inside and outside of the mag about 1/4 inch on
either side of the split. Then using the Mag adjusting tool (Vice
squeeze the out side of the mag until the seam split meets. Make sure
you put cloth or some paper towel where the teeth of the vice grips
the mag or you will chew up the outside of the mag. Lock the vice grips
in place and let sit for at least two days. Then you can loosen them up
and using 330 or 600 grit wet sand paper with water sand the outside of
the epoxy until the mag fits and is able to click tight in the mag

Another reason for jamming is excess friction in the guns internals - cock the gun, holding the trigger and observe whether it binds in either the forward or rearward "stroke."  I encountered a cocking knob that bound in my upper receiver, causing jams - I also found that my upper receiver was welded poorly (flats didn't meet flush) - which caused the gun to bind and jam.  Yes - I do have a tendency to find the weak points of all guns!



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Last modified: 01/10/10