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Posted: 12/24/2009 7:29:03 PM EDT
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From what I have researched I think my disconnector is not functioning.
the last time at the range, my AR was NOT firing a second round when i pulled the trigger. It would fire the first, then chamber the 2nd but not fire it. so I used it as a bolt action sort of, it was rather frustrating. I thought the magazine had something to do with it. So I tried different magazines, and then i got a burst fire of 2 rounds, so i am pretty sure i have disconnector issues. I know it is dangerous to use it so i have not used my AR since and have it detached and will not use it again until i bring it to a gun smith. Is this behavior typical of a bad disconnector? I tried the test where you pull and hold the trigger, hear a click, then charge it back close bolt release trigger, and then i don't hear a 2nd click. When I pull trigger, release then charge back and then close bolt and pull trigger i hear another click. BUT, when I pull trigger, hold, then charge back and then close bolt then release trigger, then pull trigger it Does NOT click. (I think this means something) I would greatly appreciate any help so I know what needs to be fixed. |
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Remove the upper, and while carefully preventing the hammer from hitting the receiver, work the trigger while manually cocking it. You will get a feel for the action.
Inspect the springs, two large and the one under the disconnector. Holding the trigger back after firing, and see if the hammer gets caught when you recock it. If it catches on the disconnector, then it should release from that to get caught at the hammer sear. If this used to work, then something broke. If it never worked, likely the clearances are bad, and you can only replace the parts. If that happens, look to Bill Springfield for a well-tuned trigger for $35 rework fee. |
| First thing to do is pull the FCG and clean out the interior of the lower to be sure nothing is floating around in there. Clean the FCG and check for any obvious burs or heavy wear. Lightly lube and reinstall the FCG, paying special attention to the orientation of the disconnector spring (big end goes down). Review the lower assembly guide to ensure everything is being installed correctly. Retry the function check. |
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Using the above guide, pull the FCG and reinstall it after cleaning, and confirm that the disco spring is install large coil side down into the back of the trigger slot.
When you go to do the function test again (after dry checking just the lower in hand alone), here is a key one. While holding the trigger back, pull the CH back and lock the bolt on the catch (empty mag helps). The hit the bolt release to let the B/C slam home. Now release the trigger quickly, and pull it again.The hammer should fall on the repull. Now do it again, but this time slowly release the trigger. You should hear a loud click of the hammer resetting to the trigger sear (not the hammer tagging the FP), and again, on the repull, the hammer should be released from the trigger to strike the FP. |
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Quoted:
While holding the trigger back, pull the CH back and lock the bolt on the catch (empty mag helps). The hit the bolt release to let the B/C slam home. Now release the trigger quickly, and pull it again.The hammer should fall on the repull. Now do it again, but this time slowly release the trigger. You should hear a loud click of the hammer resetting to the trigger sear (not the hammer tagging the FP), and again, on the repull, the hammer should be released from the trigger to strike the FP. The hammer is not falling back...when i close bolt again while holding trigger down, then i release trigger and pull it, the hammer evidently was never reset back because when i pull the trigger i hear no 2nd click. I think this explains why it was not firing more than 1 round on many occasions, And my AR worked fine the first 2 times i took it to the range in june-july i built it in June...it was when i went in august and september it wasn't functioning. Something is wrong such that the hammer is not resetting when my finger is pulling down the trigger so when i let go and then repull the hammer does nothing. |
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Shotgun the upper open or take the upper off the lower.
Grab the disco and press it back. Is there strong spring tension forcing the disco forward in the trigger, or does it just flop around? Next, hold the trigger back with you finger, and cock the hammer back to the disconnector. While holding your hand in front of the hammer, release the trigger. Did the hammer fall from the disco sear to the trigger sear, or did it miss the trigger sear and go all the way forward? |
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First, I appreciate everyone on here's time, the help is tremendous.
I actually just separated the AR and took a good look at the lower myself. Here's the problem, I found it: When I hold the trigger down and the hammer flies forward, when the hammer is pushed back to try to reset, it won't stay cocked as long as the trigger is held down...i think it is the disconnector, that is not grabbing the hammer to recock it when the trigger is pulled down. So if I pull AND hold the trigger the hammer will get pushed back in the AR and then just go forward again, which explains either bursts or a no-fire. If after pulling the trigger, release the trigger promptly then push the hammer back, then the disconnector (i think that's what it is) is able to grab the hammer. So it's like when I hold the trigger down, the hammer is just riding the bolt back and forth. |
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I just took a look at the lower, I didn't put it together originally a friend who builds AR's did it.
I took out the disconnector/trigger pin and put it in again and noticed that it when doing the function test, the disconnector actually caught the hammer even when i held the trigger down....so that part was FIXED. BUT even though it caught the hammer when the trigger was held down, when i'd release the trigger, and then pull nothing would happen. The feeling I got on the trigger when i went to pull it again after holding it down for a while and then letting go, reminds me of the feeling i got when it wouldn't fire at the range a 2 months ago, when i had to keep ejecting. I tried looking at the spring, it looked like it was in there correctly, i am having trouble taking it out, i am not that experienced. I never fired a gun until 6 months ago, which is why i had a friend built the AR for me. I am trying to learn but am not sure how to take out the trigger group properly and stopped because i don't want to break anything. I actually took out the hammer group and cannot get it back in so i am done testing for now, I'll have to take it to my friend to put in again. So basically if i hold the trigger down, there seemed to be problems, before it was that the disconnector wouldn't catch, this last time i tested, the disconnector caught the hammer, but it wouldn't release it with the next pull of the trigger, I'd then have to push the hammer back harder and then pull the trigger. Would it really be the spring that is causing this behavior? Thanks Dano for helping. BTW: my friend actually just did a functions test the other day and told me how it works fine, but it is because he was not thinking and only did the test pulling the trigger then releasing, then resetting hammer, etc repeat. The REAL problem is when I hold down the trigger, it either doesn't results in the disconnector not catching the hammer, OR it catching but not letting go on the next trigger pull. |
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Ok, Crash course time.
With just the lower in the hand, Start by removing the hammer. Uncock the hammer, and while using a punch to push the hammer pin out through the receiver, hold the hammer steady in the lower receiver/it's position. Inside the hammer is a middle J spring that catches the middle annular slot in the of the pin, and once you get the J spring past it (and hold the hammer so it does not cock sides) the pin will push out so you can remover the hammer. Note, there is also a slide groove on the pin, depending which way you push the pin out, the J spring may catch on the outer groove, and you will need to press the hammer pin past it. Again, hold the hammer so it doesn't cock sideways, and the pins will come out with only a little force needed. With the hammer and it's spring remove, you will be able to push out the trigger spring fairly easly, having the trigger, disco and it's spring loose in you hands/lower receiver. With the selector on fire, you will be able to to move the trigger forward and slide it out of the receiver cavity. With just the trigger in hand, insert the pin in it, and try to free spin the trigger on the pin. If you feel some Resistance, then the end of the trigger pin channel at the C slots are burs that you will need to remove with a small fire so the pin will rotate freely in the trigger. Next while you still have the parts out, install the disco with spring into the trigger using the pin again, and try the spin test on the pin. If the pin does not rotate, or the disco will not move back (under spring tension), then check the inside of the trigger slot, and even the end of channels on the disc for burs as well. Again, us a file to clean up any edge pin channel burs. Next, run your finger nail down the edges of the hammer rear sear, and the disco sear. If the edges of the sears have a milling bur'd edges, break out a stone and clean up the end of sear (read if the ends have burs, it will prevent the sears from releasing from each other cleanly at trigger release. Now take a good look into the void of the receiver at the end of the pistol grip screw. If the thread end of the screw is protruding into the bottom of the receiver void, then either someone did not install the grip screw washer, or the screw was too long to begin with (will need to be cut). To remove the pistol grip screw, use a wrench through the bottom of the screw. Now before you attack such, there is a spring and small detent retained by the grip. Remove the screw while holding the grip tightly to the receiver. Once the screw is out (no longer bitting any threads) slowly lift up on the grip and catch the spring (it's in a channel in the grip). The detent may not drop out of, but may stay in the receiver channel. You don't need to remove the detent, but you don't want to loose it either. Now lets say that you have screw the right length (the grip with selector detent and spring back on the receiver), the parts are debured, then take a good look at this photo to get an idea of the correct way the springs need to be on the hammer and the trigger. The hammer spring installs with the loop on the back of the hammer, and the winds winding out forward with the legs on the bottom. The trigger spring center loop will be on the bottom/front of the trigger, with the legs forward, and the disco spring installs large coil side down into the back of the trigger slot. 
Now before installing any of the FCG parts back into the receiver, CLP lube the piss out of the parts, including the pins. Trigger goes back in first, with the pin installed either direction. Install the pin just far enough that it almost gets to the center of trigger void section, load the disco on top of the spring, and while aligning the disco with the pin, finish installing the trigger pin. Same thing for the hammer spring (either direction), but make sure that you load the legs of the hammer spring on top of the hammer pin/side legs of the hammer C slots and the one of the legs seats into the exposed annular slot of the pin. Note: the pins are interchangeable. The center groove in them is for the Hammer J clip, and the outer groove on the is for one of the hammer legs to seat into. Once you have the lower back together, do the hammer cock test back to the trigger again, and remember to hold your hand in from of the hammer when you do the trigger release (both slow and fast). If the lower passes flying colors, install the upper, and do the trigger held test with the B/C crash forward to make sure that the Disco is retaining the hammer as the B/C closes hard. If all is well, then let us know. If not, post back with any problems during the pull and reinstall, or it if failed a test, let me know which one. Right now I have you just cleaning up the parts and installing them correctly, but have a full bag of tricks if needed to get the right up and running right. P.S. Eric posted the link for the install of the parts. You may want to give it a once over before pulling the parts as well. 
And yes, I type at over 80 words a min, and don't proof read half the time. Any wants to bitch at the grammar or play spelling Nazi, and I will start posting reply in French to solve that problem. |
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I took it to my friend today
He played with the disconnector spring and elongated it by pulling it. Basically I'm pretty sure the spring was too short and not creating enough of a push upward to the disconnector. It passes every function test now with both upper detached and attached to the lower. Seems 100%, I will be going to the range within a week or so to check for sure with live rounds. I am quite glad...thank you all very much for the help. Bill |
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