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3/31/2009 4:56:27 PM EDT

 My new AR has about 100 rounds through it now.  In the last 10 or so, three times, the trigger didn't fully return to the front and wouldn't fire if pulled.
If I slightly push it forward, it would 'snap' sort-of and be ready to fire.  After this, of course I was listening more closely and could hear the little 'snap' after a fire of the trigger going full forward.

 Is this normal for a new AR?  Do I need to smooth/sand something out by hand?  I was firing only 40grn fibonochi VMAX rounds, perhaps this was part of the problem, or do I just need more lube in the trigger area?

 Thanks for any advice!   Mike
3/31/2009 5:00:48 PM EDT
[#1]
sounds like a sear/disconnect issue.  If it is new, I would have it warrenty serviced.  DO NOT alter it if this is the case, the manufacturer will not honor a claim if you goof with it
3/31/2009 5:08:06 PM EDT
[#2]

 I bought the kit from Model1Sales, so I assembled the lower with their kit.  I guess if there is something wrong with the disconnector, they would warranty it, but how do I tell?    They are impossible to get a hold of on the phone, and they haven't replied to an email inquiry about a small parts order either.  I may be on my own on this one.

 What is the 'sear'?  Or is that the same thing as the disconnector?  I'll open it up and see if something is obvious, just thought I would throw it up here first since you guys have alot of experience with this stuff.

-Mike
3/31/2009 5:10:18 PM EDT
[#3]
Did you put the disconnector and hammer springs in correctly?

I'd punch the pins out again and retry.
3/31/2009 5:15:52 PM EDT
[#4]
I would also double check the assembly with the springs and makes sure things are lubed well.  This will smooth things out a bit.  

You should be able to visually inspect what is going on with the lower exposed and engage the hammer.
3/31/2009 5:28:06 PM EDT
[#5]
I put 60-70 rounds through it and didn't notice anything (mostly 55grn).  It wasn't until 6-7 rounds with 40grn that it failed to fully move forward.

 I think the springs are installed correctly.  With the lower exposed, it seems to move fine, there is very little total distance for the trigger to move.

 It seems like when fired, something may be catching on the BCG or something?  There was a definite little 'clunk' or 'click' when I pushed it forward.. although the trigger barely moved.  I noticed this same sound on subsequent fires when the trigger did move forward.

 Unfortunately the range I was one didn't allow FMJ so I couldn't try a heavier bullet.  Maybe I can sneak a test shot out my backyard tonight :)

Should I lube the trigger assembly prior to every outing?  I had lubed it up two days ago on my first round of shooting.  How 'wet' does this assembly like to be?
3/31/2009 5:28:48 PM EDT
[#6]
Disconnector spring in upside-down?
3/31/2009 5:32:18 PM EDT
[#7]

 I don't think so, large side down on the spring.  It was pretty hard to get it into the trigger assembly, it didn't really fit.  Looking at the trigger picture in the assembly section, the spring location has pretty rounded area for the spring.  On my M1S kit, it was just barely curved at all, so I had to use a punch to get the spring to seat down in there.  The disconnector seems to have full movement back and forth with plenty of tension pushing up, so I assumed that was GTG.
3/31/2009 5:34:24 PM EDT
[#8]
Quoted:
I don't think so, large side down on the spring.


That's correct.
3/31/2009 5:39:35 PM EDT
[#9]
I think I may have heard this on here somewhere (correct me if I am wrong).  But, isnt it possible to get the bolt release spring and the disconnector spring mixed up.  Could that be the case?
3/31/2009 5:41:07 PM EDT
[#10]
Is there a primer loose under the fire control group?
3/31/2009 6:05:46 PM EDT
[#11]

 Primer... I'll have to check my brass for a missing primer, guess that could have done it.  I didn't find anything when I opened it up, unless it worked itself out while firing.

  I was pretty careful about getting the right springs in the correct place, so I'm thinking at this point it was perhaps lack of lube, light bullet weight and perhaps new/tight gun syndrome.   I'll have to go to another range where I can test again with some heavier weights and some lube.

 Thanks for the suggestions everybody.
3/31/2009 6:57:41 PM EDT
[#12]
Did you use the washer when installing the grip?  When I did my last build I had the exact same problem and a kind soul here informed me that without the washer the grip screw will interfere with the trigger reset.  I installed the washer and, voila, no more problem...

Good Luck
4/1/2009 5:11:35 AM EDT
[#13]


 Ok, looks little closer at the movement/interactions of the pieces this morning and I think I know what was happening.  

 When firing, I was holding the trigger back for the duration of the fire cycle.   This caused the top curve/catch of the disconnector pin to 'rest' in the inside 'curl' on the top/back of the hammer.

 The slightest push forward on the trigger yesterday caused it to slip off and allow the hammer to fully move forward again.

 This morning, I tried to repeat this, but the disconnector would not quite stay caught on this 'curl' of the hammer. Maybe it's getting smoothed out?

 Does this make sense to anybody?  If so, do I just need to fire it some more?

Thanks again, Mike
4/1/2009 7:41:25 AM EDT
[#14]
Quoted:


 Ok, looks little closer at the movement/interactions of the pieces this morning and I think I know what was happening.  

 When firing, I was holding the trigger back for the duration of the fire cycle.   This caused the top curve/catch of the disconnector pin to 'rest' in the inside 'curl' on the top/back of the hammer.

 The slightest push forward on the trigger yesterday caused it to slip off and allow the hammer to fully move forward again.

 This morning, I tried to repeat this, but the disconnector would not quite stay caught on this 'curl' of the hammer. Maybe it's getting smoothed out?

 Does this make sense to anybody?  If so, do I just need to fire it some more?

Thanks again, Mike

Holding the trigger back through the firing cycle is called "milking the trigger", and can cause a semi-auto to "double fire" which is potentially dangerous and demonstrates a lack of control;  it's not hard to do with an M1 Garand.  Every good shooter practices  trigger pull and release - firm and definite but smooth.  

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