I thought it was semi-auto!?

[Laxjedi1]

So here's the issue -- had my AR (RRA lower with a 16" bushy flat-top upper) for about a year now, so I guess I could still be classified as a newbie. Anyway, I'm at the range the other day shooting with my back up irons. (I like to take off the optics every now and then just to change it up) On about my 3rd mag I squeeze the trigger and WHAM WHAM WHAM - 3-shot burst...humm so I figured that I accidently bump fired. I was shooting off sand bags and wasn't gripping as tightly as I normally do. Toward the end of the same mag I get a two shot burst. I noticed this time the trigger pull was shorter then normal, almost like it didn't reset all the way. My range buddies thought it was awesome, but it got me concerned so I packed it up and headded home. I got home and field stripped the rifle the only part I could find showing abnormal wear was the bolt catch.... any ideas?
Thanks
--LJ1

[DaBigBR]

The police academy I went to had an RRA that the academy owned that had to be sent back to RRA brand new because of the same problem. He (the FI) said that the turnaround was not too terrible.

Send it in.

[klmmicro]

Maybe the disconnect spring has grown weak? That would keep the spur from being caught on the hammer's back travel. We has to replace that spring on my friend's rifle when it did the same thing.

[Panzerfaust]

Don't use this rifle until this condition is corrected, because the rifle can detonate in your hand from a slam-fire...

The disconnector may be worn. It is probably the disconnector spring that is the problem, though.

I had a guy come to me once and told me he totaled his car because he shot it more than fifteen times when his gun began cycling in full-auto. He pulled the charging handle back and once he let go of it, it began shooting. He dropped the rifle and it shot the side of his car all to hell. He forgot to put the disconnector spring back in it.

Very embarassing (not to mention dangerous)

[El Duderino]

Take the upper off and do the following:
-Verify that hammer locks to the rear when pushed back.
-Verify that hammer pivots forward when trigger is pressed.
-Without releasing the trigger, push the hammer back again and verify that it locks (caught by disconnector).
-Releasing the trigger should not cause the hammer to pivot fully forward (caught by trigger).
-Hammer will fall when trigger is pressed.

[klmmicro]

Originally posted by El Duderino
Take the upper off and do the following:
-Verify that hammer locks to the rear when pushed back.
-Verify that hammer pivots forward when trigger is pressed.
-Without releasing the trigger, push the hammer back again and verify that it locks (caught by disconnector).
-Releasing the trigger should not cause the hammer to pivot fully forward (caught by trigger).
-Hammer will fall when trigger is pressed.

This is the best testing method. It sounds like he might be having an intermittent issue though and it may work without the pressures of actual fire.

Panzerfaust, the guy DROPPED the rifle because it went auto??? Sounds like someone who should not have a firearm! Also, why did the hammer not lock on the sear after the first shot?

[Panzerfaust]

Panzerfaust, the guy DROPPED the rifle because it went auto??? Sounds like someone who should not have a firearm! Also, why did the hammer not lock on the sear after the first shot?

I thought I explained that the guy didn't put the disconnector spring back in the rifle.

Put yourself in his position for a moment. You have your AR in your hand, and load a magazine in it. You take your right hand off the pistol grip and pull the charging handle back. When you let go of it, it starts shooting. SURPRISE!!!!! That's why he dropped it. When the rifle began shooting, he was only holding it with his left hand and it scared the hell out of him.

He was going to sue the company for faulty weaponry, but the discovery that the rifle was improperly assembled after cleaning changed his mind.

And I don't know about all that "this guy sounds like someone who shouldn't have a firearm" stuff, either. The biggest mistake he made was in not learning the rifle before he started shooting and cleaning it. the second was in the assumption that one piece wasn't that big of a deal. Some are that way, but others are critical. He didn't have the luxury I did when I was growing up of having people who were very knowledgeable on AR's.

[RainierArms]

My bet : disconnector spring is upside down. The fat part of the spring goes down into the trigger.

[klmmicro]

Not getting down on you Panzerfaust. I have handled 2 weapons that did the "auto" thing. One was a pistol (Glock) and the other (imagine this), an AR15. The firing pin of the rifle was "stuck" and the weapon fired when I dropped the bolt carrier. Neither weapon touched the ground and no rounds left a 15 degree pattern. 15+ uncontrolled rounds with the rifle under NO control? YIKES. If one of those rounds would have caught someone, fright makes a poor excuse is my point.

I guess I have the advantage of a military background and also a lifetime of shooting. I too often relate my experience over the actions of other and come across overly critical. Personality fault on my part I guess.

As for the function, something else must have broken. The disconnector only grabs the hammer spur on the way back. The sear should lock up the hammer once it is allowed to reset. Auto should only work while the trigger is depressed. Release the trigger and the sear should engage. More than one thing had to have been wrong for the weapon to discharge that way.

Anyway, I am not tryign to be a pill. Just alarmed when I hear things like that relayed. Makes one sort of leery about shooting next to people you don't know.

[spober]

so simply leaving out this spring will make your AR an M16? DONT THINK SO!If it were that easy I think uncle sam would move to correct this in design or simply outlaw AR15.

[El Duderino]

Originally posted by spober
so simply leaving out this spring will make your AR an M16? DONT THINK SO!If it were that easy I think uncle sam would move to correct this in design or simply outlaw AR15.


It wouldn't make it an M16 it would just make it unpredictable and dangerous. You can make any AK full auto with something that costs ten cents and is found in any hardware store. It doesn't make it controllable or safe though.

[DaBigBR]

Originally posted by Panzerfaust
I thought I explained that the guy didn't put the disconnector spring back in the rifle.

Put yourself in his position for a moment. You have your AR in your hand, and load a magazine in it. You take your right hand off the pistol grip and pull the charging handle back. When you let go of it, it starts shooting. SURPRISE!!!!! That's why he dropped it. When the rifle began shooting, he was only holding it with his left hand and it scared the hell out of him.

He was going to sue the company for faulty weaponry, but the discovery that the rifle was improperly assembled after cleaning changed his mind.

And I don't know about all that "this guy sounds like someone who shouldn't have a firearm" stuff, either. The biggest mistake he made was in not learning the rifle before he started shooting and cleaning it. the second was in the assumption that one piece wasn't that big of a deal. Some are that way, but others are critical. He didn't have the luxury I did when I was growing up of having people who were very knowledgeable on AR's.

I'd have been counting my blessings that I didn't try to load it inside my home.

[jonathon]

Standard trigger and springs or the NM two stage?

[Laxjedi1]

Thanks for all the suggestions so far. It is a standard trigger and springs. Never saw much need for a two stage on a carbine (just my opinion). I'll try doing some of the function tests you guys suggested when I get home tonight. Thanks again for everyones help. I'll let you know what I find
Thanks
--LJ1

[Panzerfaust]

so simply leaving out this spring will make your AR an M16? DONT THINK SO!If it were that easy I think uncle sam would move to correct this in design or simply outlaw AR15.

Technically, no it is not a machine gun, even. They are defined as any firearm that can fire 2 or more rounds with a single pull of the trigger. This emptied a mag without even a single pull of the trigger.

Not getting down on you Panzerfaust. I have handled 2 weapons that did the "auto" thing. One was a pistol (Glock) and the other (imagine this), an AR15. The firing pin of the rifle was "stuck" and the weapon fired when I dropped the bolt carrier. Neither weapon touched the ground and no rounds left a 15 degree pattern. 15+ uncontrolled rounds with the rifle under NO control? YIKES. If one of those rounds would have caught someone, fright makes a poor excuse is my point.

I don't mind. It wasn't me that did it. My only activity in this is to explain what happened to the guy's rifle post facto.

Yeah, it was dangerous and he is extremely lucky. That gun could have blown up on him at any point in the mag emptying, or it could have shot anyone around him, including him, once he let go of the gun. that it only totalled his car could have actually been the least of his concerns.

As for the function, something else must have broken. The disconnector only grabs the hammer spur on the way back. The sear should lock up the hammer once it is allowed to reset.

It won't if there's no spring in it. The disconnector will tip backward with no stress or tension on it, facilitating the same condition as the disconnector in an M16 (the selector switch pushes the back end of it down) The sear should lock up the hammer once it is reset, but again, no spring equals no lock-up. (I've seen it is a possibility that it can jam the disconnector into the hammer, but in this case, it didn't)

Auto should only work while the trigger is depressed. Release the trigger and the sear should engage. More than one thing had to have been wrong for the weapon to discharge that way.

In theory, you're right. All that has to happen for an AR to discharge is for the hammer to not be held back, and you disrupt the sear, and make it unable to hold the hammer back, it will slam-fire the chambering round whether you pull the trigger or not.

Anyway, I am not tryign to be a pill. Just alarmed when I hear things like that relayed. Makes one sort of leery about shooting next to people you don't know.

Hey, anything you do can get you killed, including doing nothing. I say help out those beginner shooters, and guide them. You can usually tell an experienced shooter, but they can actually be just as dangerous, as they lax on things they just always do.

My bet : disconnector spring is upside down. The fat part of the spring goes down into the trigger.

If you're referring to me, the guy had no disconnector spring in his rifle. I optically observed that. Laxjedi on the other hand could have been that.

[Alaskapopo]

Originally posted by Panzerfaust
Don't use this rifle until this condition is corrected, because the rifle can detonate in your hand from a slam-fire...


Very embarassing (not to mention dangerous)

Un no it can not detonate from a slam fire. The AR15 can not fire out of battery due to the design. The firing pin is not long enough to contact the primer unless the gun is in battey. The only way you could get the gun to detonate would be if you manadged to re-assemble the rifle without the carrier key. Then have the locking blocks line up just perfect so you could get the bolt to close then have it fire. Then it would be a 223 blowback rifle or a bomb. But thats it outside of ammo related issues.
Pat

[JWP]

there is a vid of experienced nfa owner/sot shooting his thumb on left hand as he cocked an m11/9mm subgun with 30 rd mag - sear was worn and when he charged it with his right hand it went auto - holding it lefthanded, his hand shipped forward and the muzzle covered his thumb

it happens

thing is you need to realize that it can happen and control the muzzle - guy in vid shot thumb, all rounds were downrange though - imagine the press when illegal "assault rifle/unregistered machine gun" kills people at range

like the old "hill street blues" tv show LET'S BE SAFE OUT THERE

[Panzerfaust]

Un no it can not detonate from a slam fire. The AR15 can not fire out of battery due to the design. The firing pin is not long enough to contact the primer unless the gun is in battey. The only way you could get the gun to detonate would be if you manadged to re-assemble the rifle without the carrier key. Then have the locking blocks line up just perfect so you could get the bolt to close then have it fire. Then it would be a 223 blowback rifle or a bomb. But thats it outside of ammo related issues.

Well, if this was true, then maybe you would like to explain why the auto sear on an M16 is designed to catch the hammer (also designed differently than an AR-15 hammer) and not release it until the carrier indexes the sear to let go of the hammer when the carrier is fully advanced....

As I understand it, this is a possibility. I don't really think a lot of people are going to test this idea out, to try to trash expensive rifles just to prove a point.

[Alaskapopo]

Originally posted by Panzerfaust
Well, if this was true, then maybe you would like to explain why the auto sear on an M16 is designed to catch the hammer (also designed differently than an AR-15 hammer) and not release it until the carrier indexes the sear to let go of the hammer when the carrier is fully advanced....

As I understand it, this is a possibility. I don't really think a lot of people are going to test this idea out, to try to trash expensive rifles just to prove a point.

The auto sear is there for reliable timming. If it were not there the hammer would simply follow the bolt carrier down and you would not always get reliable ignition. I did not say slam fires were impossible but that detonation is. You can get cook offs and slam fires. But the weapon will only fire with the bolt locked up so it will not explode. It just like it was fired the normal way. The firing pin in the AR15 is not long enough to contact the cartridge unless the bolt is in the closed position. Try this take your colt carrier and bolt out of the gun. Make sure the bolt is in the furthest forward position and then push on the firing pin with your finger. Slowing push the bolt back into the carrier. You will not see the firing pin until the bolt is in the locked position. Thats one of the reasons why the AR15/M16 family of weapons is actually safer than the M14 M1A family. The the M14 the weapon can fire out of battery from slame fires and be very dangerious. The AR15 can not by design.
pat

[mfkzt]

Originally posted by klmmicro
Maybe the disconnect spring has grown weak? That would keep the spur from being caught on the hammer's back travel. We has to replace that spring on my friend's rifle when it did the same thing.

So... if you install a weak spring... full auto?? :rollsmiley:

[Alaskapopo]

Originally posted by mfkzt
So... if you install a weak spring... full auto?? :rollsmiley:

Its not a reliable way to fire full auto and if you do it intentionally it will land you in a federal pen for more than 5 years.
Pat

[Panzerfaust]

Try this take your colt carrier and bolt out of the gun. Make sure the bolt is in the furthest forward position and then push on the firing pin with your finger. Slowing push the bolt back into the carrier. You will not see the firing pin until the bolt is in the locked position.

OK, I did it.

There is approximately 1/16" of travel to which the firing pin pops through the firing pin hole of the bolt. This means the back end of the headstamp could, in theory if not in practice, blast off in the event of a slam-fire.

I suspect this would not be a common occurence because of what you mentioned, but I am not one who would gamble on it, no matter how favorable the odds.