AR-15 with sticky trigger reset

[Matt-CZ]

I have a new to me Colt Sporter Target AR-15. It's very old, a pre-94 ban, but by the lack of visible wear on it I don't think it was shot much at all before I owned it.

I have noticed that, once the rifle has become dirty with say 150+ rounds, the trigger starts to hesitate to return to the forward position. Occasionally it won't return at all and I have to push it forward with my finger, at which point I get a very positive click and it's ready to fire. It's a stock Colt single stage trigger.

Cleaning the engagement surfaces of the trigger and disconnector resolves the problem until the rifle is dirty again. I am assuming that a bit of roughness on this interface is causing the problem. Is that correct?

If so, what's the best way to correct this problem? Is emory paper by hand the best solution? Or using a felt polishing wheel on a dremel tool?

Advice much appreciated!

 

[jpm]

Best way is to get one of these AR-STONER Enhanced Trigger Group AR-15 - MPN: Enhanced-Trigger-Kit

Nice smooth trigger for real short money

 

[TomMontana]

Sounds like the ammo type might be the root cause. What kind ammo are you shooting that causes your trigger group to get dirty? I don't recall ever taking out the trigger group to clean because it got too dirty. Not even after thousands of rounds using using a 22lr upper. If you're not married to keeping all the original parts, may want to consider a cassette drop in trigger.

 

[drgrant]

This doesn't make any sense to me I've gotten a bunch of ARs stupidly dirty and I've never had one where the trigger didn't want to reset on its own there's definitely a part out of spec there in the mix...... maybe an incorrectly installed spring?

 

[Matt-CZ]

Best way is to get one of these AR-STONER Enhanced Trigger Group AR-15 - MPN: Enhanced-Trigger-Kit

Nice smooth trigger for real short money

This may be the excuse I need to buy a RRA two stage trigger, but I'd like to be able to fix this regardless

Sounds like the ammo type might be the root cause. What kind ammo are you shooting that causes your trigger group to get dirty? I don't recall ever taking out the trigger group to clean because it got too dirty. Not even after thousands of rounds using using a 22lr upper. If you're not married to keeping all the original parts, may want to consider a cassette drop in trigger.

Shooting federal green tip. It's not that dirty when I take it apart. Cleaning probably isn't what fixes it, but rather the small amount of lubrication CLP provides.

This doesn't make any sense to me I've gotten a bunch of ARs stupidly dirty and I've never had one where the trigger didn't want to reset on its own there's definitely a part out of spec there in the mix...... maybe an incorrectly installed spring?

Pretty sure the springs are correct, did it exactly the way the brownells video shows. I was also having the issue before ever taking the FCG out and after. I don't think dirtiness is the root cause. I think the reset is marginal and a bit of grit makes it worse.

 

[Matt-CZ]

Found an interesting video of someone having the same exact problem. He did some very light filing and sanding to the mating surfaces. I don't feel any grit or burs when I have the parts out, but I think this may be the issue. Worst case I ruin the trigger and have to buy another GI trigger, which are pretty cheap.


View: https://www.youtube.com/watch?v=vaYBqt7cMKM

 

[RKG]

Before doing any amateur alteration of engagement surfaces, I would recommend disassembly and thorough cleaning of fire control parts, ckeck for burrs on the pins (particularly the one on which the disconnectors pivots), light lube (oil, not grease), and reassembly, being careful that the springs are not installed upside down.

 

[mac1911]

You can run the 15 min trigger job through it also.
15 Minute Practical Trigger Job for the AR-15

 

[Rob Boudrie]

As to amateur engagement of surfaces...

A friend is a 1911 fanatic and well versed in detail stripping. With no time to get to a smith before a big match, he did his own trigger job. Nice, crisp, 2lb. When he had some other work done to the gun by Bob Javery (RIP) who was a true master, he commented "someone botched the trigger job on this, the hammer/sear is only engaging on one corner". You can't always tell if a trigger job is durable by how it feels.

 

[Matt-CZ]

Polishing away at engagement surfaces does make me a bit nervous. I probably would just replace the entire FCG with a NIB GI trigger and be done with it, but I'm living that Colt lifestyle, and my calipers confirm I have large trigger pins. Hooray for me, I now have less options. Colt has discontinued these proprietary parts that no one ever wanted anyway, so I have to pay extra for NOS through third parties.

I did find a used large pin disconnect on Numrich for $10 shipped, and could order a NOS colt hammer elsewhere for only a bit more than a milspec, so that's ok. To be honest, if smoothing the surfaces my FCG improves function, I may just replace the whole thing for peace of mind. Last thing I need is a disconnect that slips.

The springs are probably original, so pre '94 vintage. Everything feels tight, but what do I know? How long are they supposed to last? Replacing springs is certainly a cheap option, so I might end up putting new ones in anyway.

Before doing any amateur alteration of engagement surfaces, I would recommend disassembly and thorough cleaning of fire control parts, ckeck for burrs on the pins (particularly the one on which the disconnectors pivots), light lube (oil, not grease), and reassembly, being careful that the springs are not installed upside down.

I hadn't consider irregularities in the pins themselves, I'll check that next. Thanks.

I had checked the FCG for obvious burs, but since I'm still having the problem I'm going to have it apart again soon and take a pick to the surfaces and really feel around for any bur. I am almost 100% sure springs are in right, but taking it back apart is the only way to be sure.

 

[bfm]

confirm I have large trigger pins.

Cry once and buy Geissele

Super Semi-Automatic (SSA®) Trigger - Large Pin

 

[Dradian]

Get a new FCG.

An ALG(Geissele sister company) ACT trigger is inexpensive and will fix your problem, plus it will feel better.

 

[AHM]

Here's some Fear, Uncertainty, and Doubt for you kitchen table gunsmiths:

5 Things You Should Never Do with Your AR-15 Trigger (And One You Might Consider)​

I might not have posted that link (honest!),
if it wasn't for this 'graf:

Most standard AR-15 triggers are surface-hardened. You may take your fine files and stones to an AR trigger and get the smoothest, lightest trigger ever. Perfect! But you cut through the hardened surface and now wear is accelerated. Then one day that perfect trigger becomes a really scary trigger, and you never saw it coming.​

 

[Matt-CZ]

Here's some Fear, Uncertainty, and Doubt for you kitchen table gunsmiths:

5 Things You Should Never Do with Your AR-15 Trigger (And One You Might Consider)​

I might not have posted that link (honest!),
if it wasn't for this 'graf:

Most standard AR-15 triggers are surface-hardened. You may take your fine files and stones to an AR trigger and get the smoothest, lightest trigger ever. Perfect! But you cut through the hardened surface and now wear is accelerated. Then one day that perfect trigger becomes a really scary trigger, and you never saw it coming.​

i'm starting to rethink even trying to polish the surfaces. I'm going to have it apart soon and try to feel around for any burs or grittiness. With any luck, the problem is the disconnect that I can replace cheaply.

If the hammer needs to be replaced, I might as well just put the money towards a match 2 stage trigger. I plan to get one eventually, but it's more money than I had intended on spending at the moment, especially since large pin options are only available from the most expensive vendors. It's a shame RRA doesn't still carry a large pin option, as they are currently about 1/3 the price of the Geissele

 

[bfm]

It's a shame RRA doesn't still carry a large pin option, as they are currently about 1/3 the price of the Geissele

I used to feel that way. Now all my ARs have SSA-E triggers except for my LMT and one beater that has the Geissele adjacent ACT Trigger. Worth every penny. Anytime I shoot someone else's AR I consider it money well spent.

That said, break it down and hose all the bits out and see if that helps the stock one. The first thing I do when someone brings by a firearm they say is not behaving reliably is break out the quart jug of M-Pro7 and a toothbrush, then properly lube and reassemble.

 

[mac1911]

You won’t cut through hardened steel with polishing compound it will just smooth out the park and break the small hard edges.
Your not trying to remove metal or change sear angles or seating.
Heck just using turtle wax chrome polish on the contact areas and pins will smooth things up some.
I still think any decent replacement trigger is a better choice.

 

[Matt-CZ]

That said, break it down and hose all the bits out and see if that helps the stock one. The first thing I do when someone brings by a firearm they say is not behaving reliably is break out the quart jug of M-Pro7 and a toothbrush, then properly lube and reassemble.

I'm hoping that a real scrub with a nylon brush will fix it. The first time I had the FCG apart I just used CLP and a few patches to wipe clean, and that seemed to have improve function a lot, though not enough to be 100% reliable. I'm hoping a proper scrubbing will fix it. The rifle was obviously in storage for quite some time and not fired much, so I'm hoping a good cleaning and some additional wear from normal use might smooth it out.

I do want a better trigger, but wasn't planning to open the wallet quite yet. We'll see.

 

[bfm]

I'm hoping that a real scrub with a nylon brush will fix it.

Yeah, really get in where the disconnector rides. If I went with something other than Geissele it would be the KE Arms one that In Range chose for the WWSD rifles. Exactly because it should be less susceptible to debris.

 

[jpm]

I was going to ask if it was large pin, in that case go with one of these...

Tsunami Arms - Colt Style Large Pin .170 Precision Drop In Trigger | eBay

I got one for my colt hbar and its a really really nice trigger. Fits like a glove with the large pins too. Supposed to be OEMd by the same folks who make Velocity Triggers.

 

[northny]

Geissele. I have two in large pin colts. They even have a version that works with pre ban colt with sear block.

 

[Matt-CZ]

I've identified the problem. There is a small burr on the corner of the hammer surface that engages with the disconnect. You can maybe see it on this photo, it's the far corner, just in front of the lint you see. It's bigger than it looks on this image, it was hard getting a good angle for the photo.


After a few sparing strokes of the file, it's gone. I am hoping that since it was the corner, I didn't affect the rest of the surface while smoothing down the burr. If you see any arrest reports for someone with a doubling AR, wish me luck.

I can't detect any hesitation on the disconnect now. I think it's cured. Function and safety test is good.

I plan to get a good 2 stage trigger in the near future, so even if I compromised the hardening, this part should be coming out fairly soon.

 

[AHM]

i'm starting to rethink even trying to polish the surfaces. I'm going to have it apart soon and try to feel around for any burs or grittiness.

Looks like you may be on the road to success,
especially because you may have done a couple of extra things
that I wrote about and then decided not to post:

1. Clean/inspect much more carefully.
2. Use too much light and too much magnification.

But, oh noes -
you didn't file off the factory case-hardened burr, did you?
(Just kidding).

 

[92G]

dude AR 15 triggers are so cheap, i would rather replace the thing than muck around with the disconnector which could resulted in hammer drop or unintentional FA

 

[Matt-CZ]

dude AR 15 triggers are so cheap, i would rather replace the thing than muck around with the disconnector which could resulted in hammer drop or unintentional FA

Unfortunately, large pin colt triggers are not so cheap, as the part is discontinued by colt. Cheapest i found is $60 for just a hammer, which is the part I need to replace. I'd rather just save that money towards a two stage match trigger.

 

[92G]

Unfortunately, large pin colt triggers are not so cheap, as the part is discontinued by colt. Cheapest i found is $60 for just a hammer, which is the part I need to replace. I'd rather just save that money towards a two stage match trigger.

interesting did not know that. i still think $60 is worth it to know youve got a legit disconnector. could also send it to colt for replacement last time i needed their CS for a 1911 they were very helpful (surprisingly)