AR-15 double fire

[davparlr]

While shooting a friends semi-automatic AR-15, I quite often got a double fire on one trigger pull. He tried and also got several double fires and maybe a triple fire. He assembled the AR-15 from good sources. Any ideas, does this happen often? The gun is brand new, although has been fired several hundred rounds before this showed up.

 

[GrauGeist]

Is the disconnector spring installed properly?

If memory serves right, it should be installed small side (taper) up, otherwise it acts all buggy

 

[Torch]

Agree or somebody messed with the sear or something else

 

[GrauGeist]

years ago, I effed up when I reassembled an AR and was getting doublets at the range. At first I thought I had the wiggly-finger, and tried again but after noticing that several people were giving me the lazy eye, I decided to take 'er back to the bench and find out what was going on. A good friend of mine (master armorer) spotted the problem right away and corrected it.

After than, never had a problem.

 

[mikewint]

Dave, I AM ABSOLUTELY SURE YOU ACCIDENTLY PULLED THE TRIGGER TWICE RIGHT!!!
A Wisconsin man today surrendered to federal authorities to begin serving a 30-month prison term for having a broken rifle, prompting the Gun Owners of America to issue a warning about the owner's liability should any semi-automatic weapon ever misfire.

"A gun that malfunctions is not a machine gun," Larry Pratt, executive director of GOA, said. "What the [federal Bureau of Alcohol, Tobacco, Firearms and Explosives] has done in the [David] Olofson case has set a precedent that could make any of the millions of Americans that own semi-automatic firearms suddenly the owner [of] an unregistered machine gun at the moment the gun malfunctions."

Officials with Gun Owners of America told WND they met with Olofson today before he surrendered to federal authorities for his prison term. U.S. District Judge Charles Clevert had imposed the sentence after the gun in question let loose three shots at a firing range.

"It didn't matter the rifle in question had not been intentionally modified for select fire, or that it did not have an M16 bolt carrier … that it did not show any signs of machining or drilling, or that that model had even been recalled a few years back," said a commentary in Guns Magazine on the case against Olofson, of Berlin, Wis.

"It didn't matter the government had repeatedly failed to replicate automatic fire until they replaced the ammunition with a softer primer type. It didn't even matter that the prosecution admitted it was not important to prove the gun would do it again if the test were conducted today," the magazine said. "What mattered was the government's position that none of the above was relevant because '[T]here's no indication it makes any difference under the statute. If you pull the trigger once and it fires more than one round, no matter what the cause it's a machine gun.'

That being said: It may be firing once when you pull the trigger and once when you release. Thats caused by the disconnector not grabbing the hammer correctly and is caused by an out-of-spec disconnector or receiver (or bad trigger job).

Perform a function check with the weapon unloaded:
1. Pull charging handle, release
2. Pull trigger hold
3. Pull charging handle, release
4. Release trigger, you should hear a 'thunk' but not the sound of the hammer falling.
5. Pull trigger, hammer should fall.

 

[davparlr]

I am a bit old and shaky.

 

[GrauGeist]

I am a bit old and shaky.

Getting old is not for sissies, that's for sure!

 

[bobbysocks]

2 things...it could be a loose grip resulting in "bump firing" (google it).....and you can do that legally as you are still technically pulling the trigger for each shot. were you shooting factory loads or reloads? another thing that happens in semi autos that will give you a double fire is bad or inconsistant ammo.....where the load is hot enough or gives enough gas to push the bolt carrier back but not hot enough to push it back all the way to engage the disconnect. most of the time it results in a stove pipe jam or not stripping a round from the magazine. but if conditions are right the result will be like the firearm shooting like an old open bolt machinegun. the bolt carrier will not latch and the spring tension will then drive the bolt forward striping a round and slam firing it.....depending on the gun it could be potentially dangerous as the firing pin may strike the primer before the round is completely seated in the chamber. you usually see this more in 22s than enything else...but could happen...i have had it happen to me. also make sure you do not have any gas leaks in the system...that could do the same thing. i would check the trigger group to make sure nothing is hanging up and all the components move freely like they should. if in doubt...do like said above..take it to a gunsmith. and mike technically that is correct....any weapon that fires more than one round without pulling the trigger each time is "a machinegun" by definition....just depends on how much of a D!c1< the atf wants to be....like all law enforcement agencies you will have some that will sluff it off and some who will run with the letter of the law.

 

[mikewint]

Bobby, Ive also seen entire clips cook-off without touching the trigger but only after lots of full auto firing. The guy mentioned in my post apparently lent his AR to a friend who took it to a public range and was shooting next to two cops who reported him to the BATF. When the BATF seized the gun it had not been repaired or even taken in to be looked at, so "let's make an example" kicked in. "Sense of Humor" not a job requirement

 

[GrauGeist]

What the BATF did to the Wisconsin man was wrong. The Feds should have had the burden of proof to show the weapons was NOT modified, making it illegal, instead of crucifying him for an equipment malfunction that was beyond his control.

Going above and beyond to crucify him like that is totally pointless. He wasn't in his front yard plinking at crows in between sips of Miller light, he wasn't in a movie theater hosing cellphone users and he certainly wasn't at a schoolyard acting out revenge for being picked on...

He was at a range, following all the rules with a permissible long arm. Obviously making an example out of him earned them a round of pats on the back from fellow world-savers in their ranks but out here in the real world, the bad guys are still roaming around and could care less about Mr. Olafson.

 

[mikewint]

Dave 110% agreed but they claimed to have no option since the law was very specific, one trigger pull one shot. No sense of whimsey in those boys. Kinda like kidding about a nuclear bomb in your shoe at an airport

 

[GrauGeist]

Well, they can claim they had no option, however the law of the land still (last time I checked) states that an individual is innocent until proven guilty of the offense. They have the ability to prove he was not in violation but they choose not to.

What they have done with his kangaroo court trial, is like prosecuting a person to the fullest extent of the law for attempted murder, assault with a deadly weapon and willful damage to property in the event of their vehicle's brake failure that resulted in a collision.

Oh well, I suppose living in a perfect world would be exceptionally boring...

 

[bobbysocks]

you all are preaching to the choir. yep, it was a bamboozal of epic proportions and they can always look the other way. but dont fool yourself that you are innocent until proven guilty. that is only in a courtof law in the main judical system. there are agencies who can and do act with out due process....most fish and game commisions are like that ...the atf is....the irs is another. they have the ability to confiscate property and incarcerate at will and only depending upon if a bug crawled up their butt that moment. that is about all i will say for fear of jumping on a huge soapbox and turning this way too political. the atf has known this definition is flawed but will not change it because as it stands it can be very useful in some sitiations if they need it to be that way.....

 

[mikewint]

Bobby, you just hit 150%, nail on the head. And ten's of thousands to attempt to prove your innocence

 

[GregP]

One thing that can happen is the gas tube can become a bit clogged and reduce the gas volume, making it fire two or several rounds.

As far as the BATF goes, the law is very simple as stated above. If you break it for any reason, they can and sometimes DO overreact. That's one very good reason for setting the gas vent on an FGAL NOT at a range.

 

[bobbysocks]

some of your "black guns" ( military rifles ) have adjustable gas vents. iirc some you could dial out the return gas completely in order to shoot a grenade ( using blank or special ammo )...

 

[tyrodtom]

One thing that can happen is the gas tube can become a bit clogged and reduce the gas volume, making it fire two or several rounds.

As far as the BATF goes, the law is very simple as stated above. If you break it for any reason, they can and sometimes DO overreact. That's one very good reason for setting the gas vent on an FGAL NOT at a range.

From my experience with a M-60, exactly the opposite is true, if the gas tube, or anything in the gas system gets dirty or partly plugged, the weapon doesn't have enough power to work the action. The result is failure to chamber the next round, or eject the fired round. I see no way reduced gas pressure, or gas volume, could result in a double fire.

There are online forums devoted strictly to the M-16/ AR-15, I'd run this problem by them.

To me it sounds like a incorrect assembly or a bad sear. If it's a bad sear, it's a dangerous defect, because it also has the potential to bumpfire.

 

[Torch]

I agree tyrodtom,the ar15 needs built up gas to cycle the bolt,if it's clogged it does not go bang on the 2nd round

 

[Night Fighter Nut]

I would need to see the weapon to see why it could be double firing. I was an armorer for awhile in my unit and may be able to help. Off hand, there are a couple of possibilities. First is a worn seer, the seer holds the hammer back after the weapon has re-cocked itself. Since this is a relatively new weapon, I don't think this as the case. A common mistake some people do when re-assembling the rifle guts is putting the long double spring (hammer spring) on incorrectly. This is the spring that pulls the hammer forward. Look inside your weapon and see where the two tines lay. If I remember right, they should lay on the bottom of the receiver. If they are on top of the seer/selector pin, there is your problem. The extra tension given to the hammer may be overcoming the seer, or the hammer is not going back far enough to properly lock in the seer. Take a look and tell me if this is the case.

Hope this helps.