AR slam fired...twice. Why?

Guinness

New member
Like the title states, I was at the range this afternoon and had my AR double tap two separate times. The gun has a new barrel and gas block but the lower is untouched since I purchased new. Due to the new barrel I was searching for a factory load for hunting to get me by while I finish my reloading bench. Anyway, several loads were shot and the double tap occurred each time I had Hornady Custom 55 grain V-Max in the magazine. Three cartridges in a 20 rd mag and the 1st trigger pull put 2 rounds down range. I thought the first time might be a fluke until I tried the same scenario and it was an exact copy. The lower has fired 500-1000 rounds. The new barrel, etc (fwiw) has less than 100 and the rifle is as new clean.

A penny for your thoughts please. I have a couple ideas but want to hear from those of you better versed in AR function.

Thanks for your input.

G
 
The first thought is the primers you are using with the free floating firing pin,,,It's possible that the primer cups are really soft/thin, or your action spring is too strong and slamming the bolt carrier forward too hard,,,,

If you have some benchrest primers or some CCI Arsenal primers, it might solve your problems..
 
I'm going with easing the trigger and bump firing a loosely held rifle. If they are good solid pulls with good pocket contact then looking to the FCG needing some new parts. Maybe a disconnect or trigger.

Greg
 
Have you checked the disconnector? Pull the lower, cock the hammer, wrap your hand over the lower in front of the hammer, pull the trigger, keep trigger pulled back, re cock hammer engaging the disco. Slowly let off the trigger, disco should let go of hammer, the hammer should rotate forward and catch the trigger.

Do this a few times to make sure its grabbing. Wouldnt hurt to tear down the bolt and clean it real good. Also check to make sure the firing pin tip isn't bent causing it to hang up.
 
Had a new one do this once when the bolt got some junk in it. Gun was wayyy overgassed, pretty violent action. Cleaned the bolt and put a adjustable block in it and it hasn't happened since.
 
Originally Posted By: GLShooterI'm going with easing the trigger and bump firing a loosely held rifle. If they are good solid pulls with good pocket contact then looking to the FCG needing some new parts. Maybe a disconnect or trigger.

Greg

This ^^^^^^^^
 
Originally Posted By: Widow maker 223Have you checked the disconnector? Pull the lower, cock the hammer, wrap your hand over the lower in front of the hammer, pull the trigger, keep trigger pulled back, re cock hammer engaging the disco. Slowly let off the trigger, disco should let go of hammer, the hammer should rotate forward and catch the trigger.

Do this a few times to make sure its grabbing.

That's what I'd do. I've had that issue with the disconnector not grabbing when I was doing some mag dumps on a lower with about 700 rounds through it. At first I thought I was milking the trigger causing the second shot when I wasn't expecting it. It happened a couple times but I thought it was operator error. The three round burst that followed shortly thereafter got my attention
ohmy.gif
I couldn't get the rifle out of my hands fast enough and I was the only one at the range. Thankfully it wasn't one a weekend with lot's of bystanders. I inspected things when I got home and found the issue was the disconnector. Not sure why or how but I had another one sitting around so I installed that one and the defective one was quickly destroyed. It took me a bit to get the stones to fire that one again even though I knew the issue had be resolved but after 1000's of rounds it still works as it should, staying a semi-auto.
 
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Thanks for the responses guys. I was on a couple of those trails myself. I appreciate the process to check the disconnector and will do that when I look over the gun today.

G
 
I can bump fire my rifles with Geissele triggers if I hold it lightly and hold it right around where it resets. Happened a few times when I shot my AR after shooting bolt rifles for a while.
 
Originally Posted By: GLShooterI'm going with easing the trigger and bump firing a loosely held rifle. If they are good solid pulls with good pocket contact then looking to the FCG needing some new parts. Maybe a disconnect or trigger.

Greg

I agree, trigger pull.
 
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