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Discussion Starter · #1 ·
Hey guys,
I have an LMT trigger group that I took out of my wife's M4 and put in my new DM bastard build. Before I swapped it we were noting a very slow reset after rounds fired. I took it down to ensure that is was assembled correctly and it was, I put it in my other build and there were times that it totally failed to reset and I had to physically move the trigger forward. I was thinking that the hammer spring might be weak, but I can't find a spare right now. Are there any other places I should be looking for problems?
 

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How about the little spring that sits in the top of the trigger under the disconnector? I guess that is called the disconnector spring.
If you decide it is the hammer spring, I have a spare JP tactical spring you are welcome to try. Just let me know if you need it.
 

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Discussion Starter · #3 ·
I appreciate it and it could very well be that.. I only checked to make sure it was present lol. I was more worried about the hammer spring.. Now that I think about the Cycle of Operations I think you might be correst.
 

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Hey guys,
I have an LMT trigger group that I took out of my wife's M4 and put in my new DM bastard build. Before I swapped it we were noting a very slow reset after rounds fired. I took it down to ensure that is was assembled correctly and it was, I put it in my other build and there were times that it totally failed to reset and I had to physically move the trigger forward. I was thinking that the hammer spring might be weak, but I can't find a spare right now. Are there any other places I should be looking for problems?
Check your trigger spring, since that's what pushes your trigger to the reset position. The disconnector spring, if weak will cause hammer follow with an occasional double (disconnect isn't going forward far enough to catch the hammer) and a weak hammer spring will generally manifest itself in weak primer strikes.

For reference, I've not had that one go out on an AR but I have had the trigger springs fail completely on a wartime P38, a postwar P1 and a Beretta 92F. All had the same symptoms of failure to reset. Also have had a very gummy trigger in a walther target pistol that was traced to the same root cause of a weak trigger return spring.

Whatever the final cause is determined to be, I strongly advise storing small springs as well as a set of gas rings for the AR. I learned a long time ago that the PITA factor is mitigated by $40 worth of spares in a baggie.

As an emergency move, you can (CAREFULLY) cold form the legs to increase spring tension. This is not recommended in a SHTF piece for obvious reasons. You can also learn the art of cold forming springs from music wire. Its not as hard as it sounds and can save you money and irritation when a spring takes a dump, particularly on some of the long out of production WW2 collector guns. Don't know if you collect, but try finding a cocking lever spring for a Sauer 38H sometime and you'll know what I mean. Numrich used to carry repros but they're long gone now.....

Good luck,
Grumpy
PS - I would also suggest you check for cracks in the spring. The common factor I didn't spell out up above is that the P38/P1/92F all use a torsion type spring and each one of them cracked (not the leg, the "wound" part of the spring). If one or the other of the two wound portions of your trigger spring has a hairline crack, you will lose tension on that leg and only one leg will be pushing, thus weak reset. No way to fix that with cold forming, just replace asap.
 

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Discussion Starter · #6 ·
I got the extra gas rings stored already, but I am having a hell of a time finding a disconnector spring. I happened to remember that I have a spare trigger laying around that one of my armory buddies gave me on my 2nd deployment. I'm pretty sure that it still has a disconnector spring in it so I will double check when I get home and see. I may just drop the whole trigger in the gun and see if that fixes it. Thanks for the help everyone and I will post any followups that I have on here.
 

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I got the extra gas rings stored already, but I am having a hell of a time finding a disconnector spring. I happened to remember that I have a spare trigger laying around that one of my armory buddies gave me on my 2nd deployment. I'm pretty sure that it still has a disconnector spring in it so I will double check when I get home and see. I may just drop the whole trigger in the gun and see if that fixes it. Thanks for the help everyone and I will post any followups that I have on here.
Try here for AR parts:

AR15 LOW RECV STOCK Accessories | Numrich Gun Parts

Not the best prices and they have been known to glitch an order so watch 'em carefully, but they usually have things when everyone else is dry. Particularly hard to find parts if you ever get the collecting bug.

Best,
Grumpy
 

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Discussion Starter · #8 ·
Yup I used them to get parts for my grandpa's old Rem 550-1 that he left me. I have ordered from them several time and have not had an issue. I never really considered tehm for AR parts though.
I will definitely have to give them a try. Still trying to get a front sight and a sear spring from them for that old remmy and a rear sight bridge for an old Winchester Mod 67A that I picked up a few weeks ago from my local pawn shop for $60.. Talk about a fun little gun! you shouldn't be allowed to have that much fun with an old single shot manual .22 :D
 

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Well, looks like they are out as well. PM if you can't find one. I'll hook you up and you can just replace it later when you find one. I think Grumpy may be right about the trigger spring though. Got one of them too. Let me know.
 

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Discussion Starter · #11 ·
I swapped the disconnector spring out and it seems to have fixed it. I haven't had a chance to actually go test fire it yet but it has a much more positive re-set now. I appreciate the help. The trigger assembly in teh LMT 2 stage group is different than any I have seen and worked on before. Its not a traditional steup and the disconnector is actually pinned in place to the trigger by a small pin (which is a PITA to drive out and replace BTW) and the whole assembly drops into the lower.

LMT-LEWIS MACHINE TOOL AR-15 2 STAGE MATCH TRIGGER

It takes a regular disconnector spring though but it the trigger and disconnector fit together REALLY tightly and with the added spring pressure was a PITA to re-assemble.

Woodstock and Grumpy I really do appreciate the help and ya'll are a big part of the reason I still stick around here. Its nice to know that there are still complete strangers out there who will go out of their way to help someone out with a problem and even drop a needed part in the mail at their expense to help someone out. I really do appreciate it!

BTW I have 5 M-14 mags if you know anyone who needs any.
 
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