Curiosity - AR "run out"

Hello there!
Just as matter of curiosity and learning, what can/did cause it?(as follow)

I went for a quick sight in with my hunting rifle and take my AR for a play in between shooting, what happen is, after i fire couple shots i pull the trigger and if fired a little burst of 3 shots as it was full auto, i saw it happening before but was just two shots then.

Can you guys with a lot more acknowledge explain it to me? Follow the rifle specs:

Stag Arms mode6 5.56, 18" bull barrel suppressed, rifle length gas tube, everything original (exception the barrel length), i have fired around 8-900 rounds thru it and only once before it happen, trigger is a 2 stages factory match.

Cheers.

Mac

Have you cleaned it including disassembling the bolt and remove the firing pin? The firing pins can get sticky and slam fire.

Yes, it is/was well cleaned, i use action blaster and am very "anal" with cleaning my rifles… Lets see what more info will come thru.
Cheers for the reply.

Just enjoy it while it last. :)

Unless your running short of ammo that is.

Cheers
Pete

I WAS going to ask "can I have a go" :D

I was actually "SMILING" after it happen, frightening at first, "funny" at the end…

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Originally Posted by P38

Just enjoy it while it last. :)

Unless your running short of ammo that is.

Cheers
Pete

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Your trigger is fucked. Go buy a new one. If it's doing that sort of thing you can't trust it and it's a saftey issue that needs to be fixed. Lucky for you aftermarket triggers are readily available for ARs.

Quote:

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Originally Posted by P38

Just enjoy it while it last. :)

Unless your running short of ammo that is.

Cheers
Pete

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It's actually abit dangerous. There's a chance you're getting hammer follow due to an incorrectly assembled sear. This could result in an out of battery detonation and destroy the upper/lower/

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Originally Posted by Daggers_187

It's actually abit dangerous. There's a chance you're getting hammer follow due to an incorrectly assembled sear. This could result in an out of battery detonation and destroy the upper/lower/

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A big + 1 on this.

Often happens a few hundred round after someone does a trigger job and removed the hardened outer layer.

If your trigger is adjustable then check its adjustments otherwise it's new trigger time as risking a out of battery detonation due to the hammer following the bcg is not cool in a ar-you would likely be ok as long as you ha e eye pro on but you whole rifle and optic are normally only good for the bin afterwards.

An out of battery discharge from hammer follow should be impossible on an AR. The carrier prevents the firing pin from reaching the primer until the bolt is fully locked.

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Originally Posted by Banana

An out of battery discharge from hammer follow should be impossible on an AR. The carrier prevents the firing pin from reaching the primer until the bolt is fully locked.

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I think "should" is the key word there as I have seen a mates( and forum member) rifle destruct from what would seem to have been hammer following according to both the gunsmiths who did reports for the insurance company

Hey guys, thank you heaps for the info, I like to add something to the latest info posted here regards "the trigger", as I mention in the very beginning I am not an expert, what I have to say is, the trigger is a match grade two stage ORIGINAL from Stag Arms, it is not adjustable and never been "worked". I always clean it with tetra gun bore/action cleaner spray, "scrub" it with a teeth brush and oil it with "CLP"(very slightly).
My new question, would a factory trigger kit warn out with less than 1000 rounds fires?

Once again, thank you heaps for the info.

Mac

The design and action of mechanism (unless tolerances are out) require the hammer to be delayed a fraction after locking to gain enough force to ignite a primer.
If you took the trigger mech out and cycled a magazines worth of ammo (over length/delayed/stuck firing pin aside) it should not fire. The hammer under tension of its spring just follows the carrier.
That's why military ones have an auto sear that is actioned by the carrier.
Hammer also has a top/upper bent where the auto sear arrests it until locked.





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Originally Posted by PERRISCICABA

My new question, would a factory trigger kit warn out with less than 1000 rounds fires?

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it shouldn't have, do you have any competent people in your area who could have a look at it?

It's likely a disconector issue.

Check that the disconector spring is present and conduct a function check.

Parts can have manufacturing flaws and as a result fail.

An in spec AR trigger will last thousands of rounds.



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Originally Posted by res

it shouldn't have, do you have any competent people in your area who could have a look at it?

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Yes @res I do, I will catch up with him sometime soon.
Cheers

What kind of ammo are you running? No chance it's really soft primers? Just a thought. I've heard of this happening on some AR10s but never heard what the cause was.

That's a interesting idea, I can always tell what rounds have been chambered but not fired by the light mark on the primer.

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Originally Posted by Savage1

What kind of ammo are you running? No chance it's really soft primers? Just a thought. I've heard of this happening on some AR10s but never heard what the cause was.

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I use hand loads, federal 205 match primers, I have shot this load for a long time now and never had any issues.