AR acting up

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NDArmyGuyret

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Joined
Jan 10, 2015
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New AR is popping off two rounds with single trigger pull. I've looked at the lower and it's the same as my others. Is this a gas issue or something else?
 
Not enough info yet. What rifle and what ammo?

Really, if it’s new, I’d be hauling my butt back to the store post haste, double quick.
 
Could be a number of things to include you causing it to double tap like unintentionally bump firing it by not properly following through when you squeeze the trigger. Since you stated that it is a new AR it may appear that there are issues with disconnector or hammer and trigger. Check and see if there is sufficient overlap on the disconnector, and whatever you do stop firing it. Call the manufacturer and tell them your issues and have them fix it.
 
Another possibility is one of the FCG pins walking out; if the hammer pin does, it usually results in doubling, then jamming as the hammer drops down on one side. Sometimes it will repeat if the trigger pin drops. The disconnector will not hold the hammer.
 
Update: changed out trigger group and put in another set I had. To the range. Did same thing. Using factory IWI 5.56 ammo and the primers look normal. Cleaned the BCG and will try again.
 
NDArmyGuyret said:
changed out trigger group and put in another set I had. To the range. Did same thing
Click to expand...
You sure you aren't milking the trigger itself?

Geissele Super 3 Gun Trigger doubling

I put a Geissele Super 3 Gun trigger in my carbine. I've been doing some load development for the upcoming season. I started out using Federal 205M primers. During range time, every now and again I would get a "double". I atributed it to the soft primers everyone says you shouldn't use in a ar15/...
forums.brianenos.com
 
The Israeli's build pretty good ammo. They have a lot of experience. But, you might try another brand just in case ….. That would eliminate that slim possibility.

You changed trigger group, cleaned BCG. You’re starting to run out of easy suspects.

What make? If a pin bore is off or the upper and the lower not well aligned …….
 
I spent some time with my Colt thinking about your problem. I had the BCG out, and can’t figure any way for that to cause a slam fire. I mean, the firing pin floats. Have to be a pretty crappy pin …….

I fondled my trigger group and played with the disconnector. I checked my safety shaft. I even took out my buffer spring and weights. Man, Eugene knew his business, and gave us a good design. I keep coming back around to ammo. If not that, then something is out of alignment. You didn’t perchance finish a kit did you?
 
NDArmyGuyret said:
Update: changed out trigger group and put in another set I had. To the range. Did same thing. Using factory IWI 5.56 ammo and the primers look normal. Cleaned the BCG and will try again.
Click to expand...
Can you remove the upper and post a picture of the inside of the lower, from the top, looking down?
 
Since you have swapped out all of the trigger-hammer parts for a different set, and you are using factory ammo that meets the eye test regarding primer height, I’m thinking it may be as @ms6852 and @MEHavey posted and you are keeping your trigger finger in a position that is causing a “bump fire” effect as it recoils and bounces about.

I did something similar myself with my Ruger MkIV and it’s sub 2lb trigger the other day, my trigger follow through wasn’t correct and I sent an unintentional double tap down range. :oops: That woke me up and I paid better attention after that oops.

Just a guess, since I’m not there looking at your gun or watching how you shoot.

Hope you find the cause and solve it! :thumbup:

Stay safe.
 
My Colt H-Bar does that... it's the only AR I have that does that. The trigger is heavy and creepy, so I'm yanking on it pretty good... and that combination can cause a double-tap. I also found, when I had it mounted, a bipod or front rest can 'assist' in a double... or more.
 
Got to the range again today and concentrated hard on trigger pull technique. I gave it a squeeze and held it and the second shot goes off so quick and then I release the trigger. Digging deeper, the trigger pull is quite hefty (as it should be..above 6 lbs), the buffer is very close to all my other ARs.. I should note that this was a complete upper kit and I had an Anderson lower, stock trigger parts came with the upper. I tried other ammo and same thing. If this is correct, why then, does it stop? My thinking is that it should leave the bolt open if the magazine is empty.
 
NDArmyGuyret said:
Got to the range again today and concentrated hard on trigger pull technique. I gave it a squeeze and held it and the second shot goes off so quick and then I release the trigger. Digging deeper, the trigger pull is quite hefty (as it should be..above 6 lbs), the buffer is very close to all my other ARs.. I should note that this was a complete upper kit and I had an Anderson lower, stock trigger parts came with the upper. I tried other ammo and same thing. If this is correct, why then, does it stop? My thinking is that it should leave the bolt open if the magazine is empty.
Click to expand...
I kind of lost track of this. Please remind me, did you assemble the lower?
 
Ammo no. Hammer not getting grabbed preventing return trip yes.
 
What brand parts in the gun? Not all are created equal. Some are far enough towards the ends of the range of in spec parts that they will not work well with other parts that are loose spec.

Decent parts are not that much more expensive. You don't need top tier parts at top tier prices, but you do need parts that meet a minimum standard to work well.

I've had problematic trigger group parts that no amount of tuning would cure. The solution as as simple as buying known good brand of parts that have a guarantee. I put an inexpensive ALG trigger group in an Anderson lower to replace the problem parts and everything worked great after that.
 
In changing out the trigger, did you swap out the disconnector/secondary sear spring? i'm thinking that rear disconnector/secondary sear isn't catching the hammer.
 
Last edited:
A test you can do to verify disconnector is working is this.
1. Clear the chamber, no Magazine
2. Verify the chamber is empty
3. Now with the safety off, confirm the gun will not fire.
3a. If it does stop right here and fix the safety problem
4. Now put the gun if "Fire" and squeeze the trigger, hammer should fall. "KEEP the TRIGGER PULLED BACK, DO NOT RELEASE"
5. Now pull the charging handle back and release to reset the fire control group.
6. Now slowly release the trigger listening for the disconnector to release the hammer for firing the next round. If no click the disconnector did not capture the hammer. If this is happening it will full auto. Not Good
7. Now see if the gun will fire a second time.

May want to do this several times, even letting the bolt fly with full velocity. It may be knocking it free of the disconnector.
 
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