AR 5.56 chambering but not firing

calicojack · Jul 7, 2019

clandestine said:
Anti Rotation Pins can cause this issue. They prevent rotation. Rotation is part of the design.

Yeah - I wasted my money on one of those KNS kits. I got an ALG ACT trigger, but left the anti-rotation kit installed. What a mistake!! The trigger felt gritty as crap. Installed the ALG FCG pins that came with the trigger and what a difference!

Now I have a KNS kit that sits in my "stupid is as stupid does" collection of parts.

[EDIT] No offense to anyone who owns a KNS kit - it just did not work well for me.

PorP · Jul 7, 2019

calicojack said:
PopP, does a simple trigger functions check pass?

From https://www.opticsplanet.com/howto/how-to-clean-ar15-inspection-and-function-check.html

1. Make sure the rifle is clear.
2. Place the selector switch on fire and squeeze and hold down the trigger. You should hear the hammer striking the firing pin.
3. While still holding the trigger, pull the charging handle fully to the rear and let go to reset the hammer.
4. Release the trigger. You should hear a mechanical click. This is the disconnector releasing the hammer onto the trigger. If you do not hear a click, or the hammer completely falls onto the firing pin,
you have a worn disconnector, hammer, or trigger and they need to be replaced.
5. Place the selector switch on safe and try to pull the trigger. The hammer should not fall. If it does there is a problem with your selector switch and/or trigger.

Jack, it does pass, this test is what confused me so much!

I was positive at the range it was a trigger group issue then at home running this test, the trigger group operated just fine.

357Max taught me 2 things.... I do have an Anderson FCG (versus Adam's like I said)

And 2, I need to learn the dang interwebs! There were multiple reviews of my FCG describing the same problem.

Thanks for the post.

3paul10 · Jul 7, 2019

PorP said:
I have no opinion on the anti-roll pins, I can only tell you why I used them.... right wrong or indifferent.

My first AR build after a few thousand rounds started firing on the trigger pull and would fire again on trigger release.

I read that this issue was due to the trigger group pins walking. I installed the anti-- roll pins and it fixed the issue. I've used them in every build since.

Again, not disputing your comment, only telling you how I got to using them.

Understood.....I do not use them, and I know Chad is against then too.....I would take them out and install factory trigger pins and see if that solves the problem. Remember, with ARs, you can have several different issues going on....that alone may not cause you problems, but when combined with other "issues" the problems come to the surface......

dist1646 · Jul 7, 2019

Check to see if there is debris under the trigger. Sometimes a loose primer of piece of one will fall out and lodge under the trigger causing the trigger to not function properly.

3paul10 · Jul 7, 2019

dist1646 said:
Check to see if there is debris under the trigger. Sometimes a loose primer of piece of one will fall out and lodge under the trigger causing the trigger to not function properly.

Another good call....and replace that anderson trigger spring with another manufacturer......

3paul10 · Jul 7, 2019

I'm still thinking, when this was happening on the range, was the trigger "dead" and could it reset by pushing the trigger forward manually? Meaning, using your trigger finger to push the trigger into reset..

PorP · Jul 7, 2019

3paul10 said:
Another good call....and replace that anderson trigger spring with another manufacturer......

Ya there is a ton of great advice in this thread. Thanks to all contributors.

PorP · Jul 7, 2019

3paul10 said:
I'm still thinking, when this was happening on the range, was the trigger "dead" and could it reset by pushing the trigger forward manually? Meaning, using your trigger finger to push the trigger into reset..

That, I did not test.

And I really should have being I just installed an adjustable trigger in my glock this week and had to do the same thing when I went a little tip far on the adjustment.

smokey · Jul 7, 2019

PorP said:
That, I did not test.

And I really should have being I just installed an adjustable trigger in my glock this week and had to do the same thing when I went a little tip far on the adjustment.

Crack open your AR, use thumb pressure on the hammer to lower it safely as you press the trigger, and take a picture down into the lower from the top so members here can see what's going on with your FCG. Then press the trigger to the rear and keep it to the rear as you use your thumb to press the hammer back until the disconnector grabs it and take a picture of it again, slightly from the side so we can see how much the disconnector is grabbing the hammer. Release the trigger until the sear grabs and the disconnector lets go and then take a picture of that. Be careful at this point, because I'm thinking the hammer may drop when moving from the disconnector to the sear and you don't want it to fall on your lower.

1time · Jul 7, 2019

It is a trigger issue or lower issue. Something is out of spec, which is why it was firing on the release. You covered up the problem with the KNS pins and because it was barely working right with the band aid fix, it wore pretty quickly and you have an issue.

The bolt carrier and hammer moves much more violently than you can operate by hand. When you run the bolt by hand, it stays cocked. When it is fired the bolt carrier is running too fast to stay cocked. Had the same issue last month with an AR gold trigger that came out of adjustment and had to shoot a 3gun stage manually throwing half of my ammo on the ground to be able to shoot the other half.

If it is a factory trigger group, take it out and beat it with a hammer. Or save it for a Clandestine class.

I’m sure I have a few extra mil spec style trigger groups. You are welcome to one of them. If you are interested, PM me.

jrhzn · Jul 7, 2019

PorP said:
For clarity....

I pull the trigger. The round is fired, spent case ejected, new round is chambered.

At this point the trigger will not travel.

When I said im pulling the charging handle, I'm only pulling it fast enough to set the trigger but not fast enough to eject the round.

Got it!!! Thanks for the clarification.

PorP · Jul 7, 2019

smokey0118 said:
Crack open your AR, use thumb pressure on the hammer to lower it safely as you press the trigger, and take a picture down into the lower from the top so members here can see what's going on with your FCG. Then press the trigger to the rear and keep it to the rear as you use your thumb to press the hammer back until the disconnector grabs it and take a picture of it again, slightly from the side so we can see how much the disconnector is grabbing the hammer. Release the trigger until the sear grabs and the disconnector lets go and then take a picture of that. Be careful at this point, because I'm thinking the hammer may drop when moving from the disconnector to the sear and you don't want it to fall on your lower.

Smokey, I'm happy to take pictures and post if it's going to solve curiosity or be a teaching point.

Otherwise, 357Max pointed me to a link where this is a reoccurring issue for other owners which in turn influenced me to buy another FCG.

Let me know if you'd still like the pics posted.

1time · Jul 7, 2019

Just searched Adams Arms trigger. First thing on there is an AA YouTube video of an AA trigger firing in the release. I also didn’t see the trigger on the website.

I would get rid of that trigger group.

Edit: missed Max357’s post.

PorP · Jul 7, 2019

1time said:
It is a trigger issue or lower issue. Something is out of spec, which is why it was firing on the release. You covered up the problem with the KNS pins and because it was barely working right with the band aid fix, it wore pretty quickly and you have an issue.

The bolt carrier and hammer moves much more violently than you can operate by hand. When you run the bolt by hand, it stays cocked. When it is fired the bolt carrier is running too fast to stay cocked. Had the same issue last month with an AR gold trigger that came out of adjustment and had to shoot a 3gun stage manually throwing half of my ammo on the ground to be able to shoot the other half.

If it is a factory trigger group, take it out and beat it with a hammer. Or save it for a Clandestine class.

I’m sure I have a few extra mil spec style trigger groups. You are welcome to one of them. If you are interested, PM me.

Agreed on all points.

Just one clarification that the issue that caused me to start with KNS pins was my first AR build.

The AR in question for this thread is build 6, 7 , 8.... or where ever I'm at now.... lol. This AR started life with the KNS pins.

1time · Jul 7, 2019

PorP said:
Agreed on all points.

Just one clarification that the issue that caused me to start with KNS pins was my first AR build.

The AR in question for this thread is build 6, 7 , 8.... or where ever I'm at now.... lol. This AR started life with the KNS pins.

Gotcha, I misunderstood.

PorP · Jul 7, 2019

So, with all the great advice in this thread...

What is the trigger group that is most rugged. Ironically I built this thing as a beater to fire every time regardless of ammo type.

It's a 7.5" pistol so i don't care about dual stage or 3lbs pull weight and I'm not trying to shoot Washington's eye out of a quarter at 100 yards.

Only to have a gun that will shoot steel case ammo after it soaked in mud for a week.

If the la rue is that trigger group, then roger that.

Squaregrouper · Jul 7, 2019

PorP said:
So, with all the great advice in this thread...

What is the trigger group that is most rugged. Ironically I built this thing as a beater to fire every time regardless of ammo type.

It's a 7.5" pistol so i don't care about dual stage or 3lbs pull weight and I'm not trying to shoot Washington's eye out of a quarter at 100 yards.

Only to have a gun that will shoot steel case ammo after it soaked in mud for a week.

If the la rue is that trigger group, then roger that.

Many will agree that LaRue trigger groups are the best quality to dollar ratio on the market.

1time · Jul 7, 2019

For a mil spec style, the ALG is a good trigger for around $70.

There is nothing wrong with a standard trigger.
My offer still stands. I’ve replaced all my triggers with match triggers and have a pile of factory triggers collecting dust.

clandestine · Jul 7, 2019

Even good triggers can have these issues. The video addresses what to look for.

PorP · Jul 7, 2019

clandestine said:
Even good triggers can have these issues. The video addresses what to look for.

I did watch your video, I'm sure I'll consult it a few more times. Thank you for posting it.

AR 5.56 chambering but not firing

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