One trigger pull, two bangs

[hog slayer]

Hammer, trigger, dis-connector springs worn or installed incorrectly. Hammer and dis-connector catch points worn and no longer catching. Worn hammer and trigger holes or pins can also allow hammer and dis-connector to miss each other. Try new lower build kit and see if that corrects it.

Currently has the rebuild kit installed. Replaced the previous one to solve same problem. It worked for a bit.

 

[Doug]

If there is insufficient contact by the disconnector, it will release the hammer before the sear is fully engaged. This is usually caused by an inexpert trigger job. When you reduce the sear engagement to lighten the trigger pull, you must increase the disconnector engagement to avoid releasing the hammer when you release the trigger.

 

[T-DOGG]

View attachment 53495

I've got one stock AR. I'm using it to make comparisons and can see no spring differentiation. What I have identified is a bit of difference in outside diameter of the trigger pin and the lower receiver. You can see a bit of variance in the hammer pin, too. Like the video, I've shot thousands of rounds thru this gun. I cannot seem to duplicate the malfunction on the bench,either.

Am I the only one noticing the pins are significantly smaller than the holes in the lower? I would imagine this would be the problem.

 

[T-DOGG]

I think your Colt lower uses .171" diameter hammer and trigger pins, but you have installed standard diameter AR15 pins (.154").

https://www.google.com/url?sa=t&sou...ggaMAA&usg=AFQjCNHv8kramV7dlksyxk6F-e87wBpXag

 

[Old Dog]

I did not expand the picture until just now, and I think T-Dogg has the answer. Colt used large hammer & trigger pins at one time (.169 -.172) Check Brownells' or Gisele's web sites for info. The slop induced by your current pins could be the cause of doubles.

 

[hog slayer]

That would make perfect sense. I will see what I can do and keep you updated. Thanks for the effort, fellas. It's been a huge help just knowing I wasn't going to be "hiding" a problem without trying to fix it.

 

[Doug]

If there is play in the pivots of the components, that could keep the sear from restraining the hammer before the disconnect releases it. With loose pivots, it might even be intermittent.

 

[RobbyMaQ]

I have zero knowledge when it comes to the pins.
I had a similar experience with an ar someone built for me by a friend. I recall him stating 'I did some trigger work on it'. 500 rounds into it, it started firing on the reset. Filing/polishing on the hammer and such is a no no, since it removes the hardened coating. I replaced the hammer and disconnector, which resolved my issue. ymmv.

 

[DoggyDaddy]

I have zero knowledge when it comes to the pins.
I had a similar experience with an ar someone built for me by a friend. I recall him stating 'I did some trigger work on it'. 500 rounds into it, it started firing on the reset. Filing/polishing on the hammer and such is a no no, since it removes the hardened coating. I replaced the hammer and disconnector, which resolved my issue. ymmv.

Nowdays they call that a binary trigger... you were just ahead of your time!