AR-15 double firing

CK · 08-01-2020, 22:13

My AR sometimes fires of two rounds, especially if I'm shooting at longer distances and thus pulling the trigger slowly. A quick search on the net points to a possible defective disconnector and or disconnector spring. I inspected them both and the spring seems fine, the disconnector does seem to have some slight wear. Has anyone ran into this issue before, or who can I speak to that can assist me to have it sorted?

**Adoons** · 08-01-2020, 22:56

Is it still an original "Mil Spec" trigger or some aftermarket "improved" trigger.

I have a Nord Arms adjustable trigger. After installing it (doing it self) and setting it to my liking with dry fire and then testing it live, it would do the same when for instance zeroing the scope or just firing slow and accurate. The 2 shots is just because that by the second shot you had time to pull the trigger far enough for it to engage the "hook" of the disconnector that is supposed to "catch" the trigger so that the sear can engage it on the reset again. When setting it very light the hook miss the catching part and it turns to full auto, but as you keep on pulling and recoil makes you to tighten your grip, the ongoing trigger movement gets the hook to make contact by the second shot. If deliberately concentrating on keeping the trigger at the point of release it even went to fire 5 rounds on full auto once. I just backed down a bit on the softness of pull and the problem is solved. (Note: It is not on my competition gun! Will never go to a range with such a light trigger. I use it for varminting mostly.)

CK · 09-01-2020, 06:59

Originally Posted by Adoons

Is it still an original "Mil Spec" trigger or some aftermarket "improved" trigger.

I have a Nord Arms adjustable trigger. After installing it (doing it self) and setting it to my liking with dry fire and then testing it live, it would do the same when for instance zeroing the scope or just firing slow and accurate. The 2 shots is just because that by the second shot you had time to pull the trigger far enough for it to engage the "hook" of the disconnector that is supposed to "catch" the trigger so that the sear can engage it on the reset again. When setting it very light the hook miss the catching part and it turns to full auto, but as you keep on pulling and recoil makes you to tighten your grip, the ongoing trigger movement gets the hook to make contact by the second shot. If deliberately concentrating on keeping the trigger at the point of release it even went to fire 5 rounds on full auto once. I just backed down a bit on the softness of pull and the problem is solved. (Note: It is not on my competition gun! Will never go to a range with such a light trigger. I use it for varminting mostly.)

Thanks for your reply, no its still the standard trigger that came with the gun, also no work done on it.

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**Kaptein L** · 09-01-2020, 07:15

Have you checked the firing pin that it is not stuck or get stuck in certain situations ?

**mic** · 09-01-2020, 07:24

It may simply be that you are "bump firing" the gun by accident. Slowly pulling the trigger on a semi-auto in not the best of practices. When you gently squeeze the trigger on a semi-auto rifle the recoil generated by the round going off and the loose finger in the trigger guard might cause and unwanted discharge. When the rifle moves forward again, making contact with the trigger finger which is not pulled tight against the trigger, another round could be fired off. My Type 56 does this every time you do not follow trough on the trigger pull.

Test:
Take a full mag. On each round, deliberately pull the trigger tight and deliberately keep your fist closed on each shot. If you still get multiple rounds going off then you have a problem with the rifle. If not, then the problem is with your grip / trigger finger.

**M43** · 09-01-2020, 07:40

I had the same problem on my AR. It would double when I fired for accuracy. And it wasn't a bump fire. We could make the hammer fall by releasing the trigger slowly with no upper installed. Hailstorm fixed it for me. we replaced the whole trigger / hammer group with a Geiselle ACT trigger and hammer.

On some guns a little wear apparently can cause doubling. Get a new trigger. You may need the gun in an emergency and you do NOT want a gun that may fire if bumped or placed down when SHTF.

**Vaal** · 09-01-2020, 09:32

When my new Stag started to double tap I also thought I did the "bump fire move" but I didn't. It only happened when releasing the trigger very slowly to reset after a shot. If you release the trigger fast, it reset as normal. The root cause was that the under side of the disconnector (where it rests on the trigger) had a burr on that edge, due to the manufacturing stamping process. For a test, I put a single piece of A4 paper between the disconnector and trigger, then the hammer didn't latch, that was how close the tolerance was between latching and not. After removing (with a jewelry fine file) a bit of the powder coating paint on the burr, the problem was gone. NB if you want to test the trigger while the rifle upper is removed, remember to pad the hammer very well where it will stop against the frame, otherwise you have a very good chance of damaging your hammer or frame. I used a piece of leather combined with a piece of cloth stuffed in that gap and at the same time I used my thumb to stop the hammer.

**Speed_Freak** · 09-01-2020, 10:48

I had a similar issue with the old trigger on my rifle.
It appears the previous owner tried to lessen the trigger pull on the factory trigger by sanding down the sear and disconnector, resulting in "Squeeze trigger, bang, release trigger, bang!"

This was not a common occurrence but happened enough that I yanked the old trigger out and replaced it with a Wilson TTU. The single stage triggers work well for me so I replaced my M&P15-22 trigger with a CMC Trigger and will likely do the same with my new rifle when finances allow.

**AK-Gunner** · 09-01-2020, 11:16

The civvy firing mechanism is usually pretty hard to make bump fire shooting prone unless it's been tweaked for at least to some extent. I concur with the analysis with the disconnector failing to hold the hammer properly, the reason being either on the hammer or the disconnector itself, or both. It's very easy fix to an AR savvy gunsmith, since you don't have to replace the whole mechanism, just the failing part. I'd start by replacing the disconnector to a new one.

**A-R** · 09-01-2020, 14:12

I have seen that happen on the range a few times.

One instance was a friend's almost new NEA. Trigger was faulty and the shop replaced it.
A second one did the same and the owner replaced the trigger with an after-market unit.
Another was a suppressed AR that got so dirty from the blow-back through the barrel that the crud build-up on the sear caused it to act up.
Then there was one that pierced a primer and got a piece of primer cup stuck in the firing pin channel.