Warning if you want an Armalite AR10T.

[355sigfan]

Be prepared to buy a good aftermarket trigger for it. Well I took my AR10T out again today. I was shooting with a friend. Anyway we were having fun when something funny happened. I was holding the trigger back during recoil so the gun would not double. It doubled on me twice and three times for my friend. Anyway when I let off the trigger nothing happened. The trigger did not reset. The hammer did not cock. I checked the chamber and fresh round had been chambered. Everything in the feeding and extraction cycle happened, as it should except the hammer did not stay cocked. It must have slipped the sear and followed the bolt carrier forward. I am starting to think the bump firing problems I have had may actually be a trigger, hammer sear engagement problem. Anyway the new trigger should be here soon. I was wondering if I would have to replace the hammer as well. Other than this flaw the gun was a hoot to shoot and the groups were fairly good.

The first shot from a cold bore was 2 inches low like my last time out. This is a good thing. Because if it is consistent I can correct for it. I will just have to remember to aim 2 inches high for the first round. Although these problems are starting to make me see why Bolt actions are the preferred 308-sniper platform.

PAT

 

[AK103K]

I'd be willing to bet, that if you have been "bumping" your rifle, that this is the cause of the problem. I would also bet that Armalite would consider it abuse. Personally, I think it is and I also think its an unsafe act, but thats just me. I dont understand why you need to "think about" holding the trigger to the rear. Seems that would be very distracting. You should just pull the trigger and not worry about anything but your sights, it will take care of itself. If not, something is wrong. Did this problem occur before you started "bumping" it or after?
I dont understand the cold bore/2" low thing either. That sounds more like something your doing rather than the rifle. Maybe its your trying to hold the trigger back when you shoot. Your first shot isnt trying to compensate for it like the ones that follow.
Keep in mind, if your close to the target and holding right on it, you will be about 2" low as thats the difference between the sights and the bore.

 

[TechBrute]

http://www.ar15.com/forums/topic.html?b=3&f=62&t=160322

 

[Nero Steptoe]

Couldn't help but notice that this exact thread has been pretty satisfactorily covered on GT, in the "Highpower" forum.

 

[355sigfan]

I'd be willing to bet, that if you have been "bumping" your rifle, that this is the cause of the problem
END

Read my post I covered the bump firing posibility. That might explain the doubles but not the hammer not remaining cocked. The first shot flyier was also a problem in a recent article where an AR10 was evaluated. This combined with the fact that I don't somehow make my Rem 700 have a first shot flyer. Also if I am the cause of the problem why does the problem not surface when I fire my chiefs SR25. Heck why has the problem not showed its face with my M1A that I used to own or the FAL's I have shot. This is not the first semi auto 308 I have shot. Anyway I have a new trigger on the way we will see if that cures the problem.
PAT

 

[Kharn]

I was holding the trigger back during recoil so the gun would not double.

The hammer was dropping when you released the trigger in addition to when you pulled it?
Your disconnector isnt grabbing the hammer correctly. Either the trigger and hammer pins are slightly out of place (0.002" farther apart from spec position will do it, IIRC), or your trigger group needs a little tuning. I doubt your lower was made wrong, but you might want to check it with a milling machine and centerfinder. Try filing a very little bit off the bottom surface of the disconnector tail and see if that improves things.

And you bump fired an AR10T?!

Kharn

 

[355sigfan]

Thanks Kharn but it was not firing on release as you described. Which as you said would be a disconecter issue. But rather the hammer was following the bolt carrier forward and not staying cocked. Probably a hammer trigger sear engagement issue.
PAT

 

[Kharn]

How old is this rifle? How many rounds have you shot through it?
Do you have an AR15 you could borrow a trigger group from?

Kharn

 

[goon]

On the topic of bumping, can't the gun fire out of battery when you do that?
I mean, since there is no auto-sear to "wait" until the gun is locked up, couldn't it fire while the bolt is still closing?

 

[Andrew Wyatt]

yeesh. he said bump firing might have been the cause of the doubles, not that he did it on purpose.

 

[AK103K]

yeesh. he said bump firing might have been the cause of the doubles, not that he did it on purpose.

What the hell does that mean? Are you a politician
or a CNN poll question writer?

 

[Andrew Wyatt]

it's possible to bump fire an m-1A without actively causing it to happen by not holding it tight enough. it's possible the same thing happened with his ar 10.

 

[AK103K]

OK, I understand what your saying now. The way his post read I took it to mean the other, intentional bump firing.

 

[355sigfan]

On the topic of bumping, can't the gun fire out of battery when you do that?
I mean, since there is no auto-sear to "wait" until the gun is locked up, couldn't it fire while the bolt is still closing?

END

I was not bump firing on purpose. Also the AR15 series will not fire out of battery. If the bolt is open at all the firing pin will not reach the chamber.
PAT

 

[355sigfan]

The rifle is brand new with less than 200 rounds on it. And I have a new trigger on the way.
PAT

 

[Badger Arms]

Pat:

As you described the problem, you might have a disconnector that is not properly engaging the hammer. A good cleaning of the trigger 'groove' in which the disconnector rides would probably clear up the problem. If there is a burr or other obstruction in that groove, the secondary sear (or disconnector) will fail to reliably hold the hammer back. Without a more thorough examination of the gun, that's about all I can tell you. Do you know how to disassemble the trigger group without damaging the gun?

By doubling, do you mean that you 1) pull the trigger and hold it back and then get two shots; 2) you pull the trigger back and get one shot and then release it and get another; 3) or a mix of these two things? You can 'reliably' get the gun to duplicate condition (2) when you by placing an obstruction under the front of the disconnector or filing the engagement surfaces. This releases the hammer when you release the trigger. Two shots per pull and release of the trigger reliably. Condidion (1) and (3) are more likely a burr, minimal sear engagement, or other obstruction preventing safe engagement. A good cleaning and inspection will almost always solve these problems. From the factory, Armalite parts have a very healthy amount of sear engagement. Unfortunately, I have never examined one of their match trigger assemblies which are included with the gun. Is it adjustable? If so, just back off of the adjustments some.

 

[355sigfan]

Badger thanks for the post. I just compleated an armorers school for AR15's myself. Its not firing on release. What happens is it doubles when I release the trigger prior to the recoil breaking on the shot. When I hold the trigger and ride the recoil the hammer simply follows the bold carrier forward and does not fire the round in the chamber. I have a new trigger on the way complete with a new disconecter. I will see if that cures the problem if it does not I will buy a new hammer. I am through trying to work with Armalite on the issue they were not much help. Their warranty is not worth the paper its written on.
PAT

 

[Badger Arms]

Is it the trigger in the picture above? Is it adjustable? Perhaps it came from the factory with too-little engagement and this can be corrected by adjustment? I'm sure a new trigger will solve the problem, but others might have the same problem.

 

[Kharn]

What happens is it doubles when I release the trigger prior to the recoil breaking on the shot. When I hold the trigger and ride the recoil the hammer simply follows the bold carrier forward and does not fire the round in the chamber.

So if you tap the trigger and remove your finger as quickly as possible, it fires, but if you hold the trigger down, the hammer drops but does not ignite the round?

Kharn

 

[355sigfan]

To be honest I was going to wait until the Knight trigger came in to take the trigger and hammer out.
PAT

 

[355sigfan]

I am sorry for not being clear. This is what happens. It normally fires when the trigger is pulled. What sometimes happens is that the gun fires twice when the trigger is pulled if constant pressure is not held on the trigger while the gun recoils. Sometimes when the trigger is held to the rear following a shot I go to let the trigger reset and fire another round and the trigger does not reset. I take the mag out and check the chamber and their is always a loaded round in the chamber. The amount of effort to check the chamber tells me the hammer is not cocked.
PAT

 

[Kharn]

I'd try cleaning the trigger and disconnector channel, trying a different disconnector spring and then try filing a little bit off the disconnector tail. Taking apart the trigger group is easy to do, and just dropping in another trigger will only cover up your problem instead of getting to the bottom of it.

Kharn

 

[355sigfan]

Kharn. Thanks I understand its easy. Like I said I just compleated a Colt Ar15 Armorers course. But the reason I am hesitant to make this trigger work is it has been back to Armalite 2 times. I am simply tired of dealing with it. Besides I like the pull better on the KAC trigger. I tried in on my chiefs SR25.
PAT

 

[Art Eatman]

AK103K, re your comment, "I dont understand the cold bore/2" low thing either."

I've occasionally had a bolt-action rifle where the first shot from a cold AND clean barrel would be an inch or two off from the next five or ten shots. No idea why.

One of my father's sporterized Springfields always shot 2" high, the first shot from a cold barrel. The next umpteen rounds would hold a tight group and impact where intended, 2" high at 100 yards. He rebedded the rifle, and then later changed the barrel--and no change in behavior. Go figure.

, Art

 

[AK103K]

Also the AR15 series will not fire out of battery. If the bolt is open at all the firing pin will not reach the chamber.

This isnt the only reason it can slam. The M1 Garand has a firing pin block that is supposed to block the firing pin until its in battery, but that still doesnt guarantee it wont slam, I can personally attest to that. All it takes is a high or sensitive primer and some knucklehead doing the "bump". Actually, it wouldnt even take that to make it slam. Never say never with anything mechanical.