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M4 Disconnector Problem?


Stevejg16

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I think it will be ok. I took so little off the hammer it’s hard to tell.

At least now I know how to do the function test! If it isn’t working perfectly, I can use the oem hammer since the trigger guard gives me a new 922r point. Then I can try to buy another FFT hammer alone or worst case, buy another set. 
 

After your input; Todd’s. and other research plus seeing it with my own eyes, I have learned the shortcomings of that polymer oem trigger guard.

 

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Looks great! What part of California are you from? I've hung out in the Mojave a lot. Being in California, do you have that stock pinned? If not, be careful.

 

I'd run a little lighter on the lube. With the trigger pack, you want a lubricant on the pivot points of the components held in place by the trigger pin bushing. Then wet to the touch on the the breech latch and the face of the hammer. On the sear contacts, you want a good grease like Brian Enos' Slide Glide. I like their grease since it doesn't stink when it gets on your hands.

Running super wet doesn't give you much benefit in performance and tends to collect carbon and shot buffering media that flies around while the action is cycling.

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Took the M4 out shooting today to test the A&S with my FFT FCG parts. Everything worked flawlessly. All problems solved.

I noticed the new trigger guard goes in and out of the gun much more easily than the original plastic one, a nice benefit. The pin that holds the trigger guard in has a more precise fit and that pin requires no force (the factory setup required me to hook the bolt handle under the head of the pin and pull out, as described in the M4 manual).

 

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  • 3 months later...

I own a M1014 with several FFT parts installed including FFT's NP3 trigger kit.  My NP3 trigger kit resides in an A&S Trigger/Frame.

As many have described in this "disconnector fails to re-set" thread- after installing the FFT and A&S assemblies, the disconnector would hang up on its mated catch-tang on the hammer after a round was fired.   The hammer re-set after the round was fired, but stayed in the far-down position, captured by the disconnector after the trigger was released.  The fix was relatively easy if one is competent in the use of tools; familiar with the dis-assembly and re-assembly of the FCU, and understands the interaction between FCU components and sub-assemblies during the cycles of the gun .  Using graduated coarseness diamond files like those from DMT, in measured very small increments, remove material from the disconnector tang, being careful to keep the tang perfectly square.  Mark the area for material removal on the disconnector with a Sharpie pen as a guide to insuring that material is removed uniformly across the tang; the material removal essentially shortens the length of the release face of the tang, so the disconnector tang can slip past its mated tang on the hammer when the trigger is released after firing.  I advise going from Medium coarseness to Fine, to Super-Fine during each grinding/polishing step.  Be very careful to remove only a slight amount of material; put the FCU back together, test, repeat until proper function is achieved.

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  • 1 month later...

Thanks for posting this thread. Ran into the same problem on a recently purchased M4 with a polymer trigger housing and the FFT trigger kit. Replaced the FFT disconnector with the Benelli part and it runs fine. Thought about leaving it that way, but have the A&S trigger housing on the way.

Comparing the two disconnectors, the engagement surface on the Benelli part is is angled such that it is parallel with the engagement surface on the hammer. On the FFT part, the angle is such that the hook on the hammer will be drawn into engagement with the disconnector notch. That would require more force from the trigger spring to push the hammer hook up hill and out of the disconnector notch when the trigger is released. It's a bit hard to tell, but the Wolfe spring in the FFT kit does feel lighter than the Benelli spring.

That's in addition to the problem of there not being enough clearance between the hammer hook and disconnector notch to let them pass each other when the trigger is released. To fix that problem, I'd be more inclined to remove material from the hammer. The hook cut is much deeper than the notch on the disconnector, and it seems like you'd have a much better chance of preserving the amount of contact surface between the two parts by cutting down the hammer hook. Or am I missing something?

triggerFFTDisconnectorFFTCaught.jpg

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5 hours ago, RedNeck Geek said:

Thanks for posting this thread. Ran into the same problem on a recently purchased M4 with a polymer trigger housing and the FFT trigger kit. Replaced the FFT disconnector with the Benelli part and it runs fine. Thought about leaving it that way, but have the A&S trigger housing on the way.

Comparing the two disconnectors, the engagement surface on the Benelli part is is angled such that it is parallel with the engagement surface on the hammer. On the FFT part, the angle is such that the hook on the hammer will be drawn into engagement with the disconnector notch. That would require more force from the trigger spring to push the hammer hook up hill and out of the disconnector notch when the trigger is released. It's a bit hard to tell, but the Wolfe spring in the FFT kit does feel lighter than the Benelli spring.

That's in addition to the problem of there not being enough clearance between the hammer hook and disconnector notch to let them pass each other when the trigger is released. To fix that problem, I'd be more inclined to remove material from the hammer. The hook cut is much deeper than the notch on the disconnector, and it seems like you'd have a much better chance of preserving the amount of contact surface between the two parts by cutting down the hammer hook. Or am I missing something?

triggerFFTDisconnectorFFTCaught.jpg

Agreed Redneck. The hammer is much easier to keep the file straight on. You want a file with a safe edge so you can hold it against the body of the hammer without doing any damage while you take a few thousandths off the disconnector sear engagement on the hammer. You go slow with the trigger pack assembled so that you can cock the hammer and see how close you are to clearing. Release the hammer and take a few more licks off. It'll move from hanging up all the time to hanging up until you press on the hammer, to passing right by the sear hook unless the trigger is pulled to the rear.

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  • 2 weeks later...

Thanks SD. I went ahead and ordered an A&S trigger housing, hoping it would fix the problem with the FFT disconnector. Unfortunately, it didn't. So I used a coarse stone to take abut 0.30 off the disconnector spur on the hammer, and got enough clearance between the two to eliminate the problem. I've since put a couple boxes of shells through it with no problems birdshot, 00 Buck, and slugs. When the disconnector is engaged with the hammer, the engagement is to the full depth of the disconnector notch, and the disconnector notch is just as deep as it was then it came from FFT.  And there's still plenty of depth left on the hammer side of the notch.

I've got more money tied up in aftermarket parts  for this thing than any of my other shotguns are worth. But it's the only one that doesn't bruise my face and shoulder, and it comes back on target quicker, too. There's nothing else I'd rather have on my side in a fight, and it's hard to put a price on that.

This shot shows the lack of clearance:

triggerFFTDisconnectorFFTHousingA&SCaught.jpg

 

This is after stoning the hammer spur.triggerFFTDisconnectorFFTHousingA&SHonedFixed.jpg

triggerFFTDisconnectorFFTHousingA&SCaught.jpg

Edited by RedNeck Geek
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