AR-15 firing out of battery

[roklok]

I often read reports and comments to the effect of an AR-15 or AR -10 type rifle, firing out of battery. It has been the reason given for numerous AR "kabooms."

I simply do not see how this is possible, at least in a standard rotating bolt version. Examination of my rifles show that the firing pin tip does not extend past bolt face until the bolt is in fully locked position, plus some. The tip does not protrude until the cam pin is fully rearward in the carrier, past the point where the bolt is fully locked.

I do not own an AR 15 chambered in a cartridge with a blow back operated upper, so I am not sure about those.

So....is an AR-15 firing out of battery a myth ? Only happens on blowback chamberings ? Happens because of out of spec parts ? Happens because something other than the firing pin is igniting primer ? What gives ?

[Palmetto-Pride]

I agree I don't really see how it can happen either, but I also haven't heard the rumer as like you have and I consider myself in the know on most AR problems

[roklok]

I have read quite a few threads about AR-15 blowups, and firing out of battery is usually brought up, with someone asserting that it is possible. That is the reason for the question.

I was reading this : http://308ar.com/trigger.htm

The writer said that an AR -10 could fire without the bolt being fully locked in place. I think he is full of crap, as it just is not possible, in my mind.

[Matt Mc]

The saving grace for rifles is that the ejector and extractor prevent the base of the cartridge from becoming flush with the bolt face on feeding. What if they were both worn out? The collar on the firing pin could be warn or of the wrong type. Firing pin retaining pin damaged and the rear end of the bolt damaged, causing the firing pin to ride too far forward. Using a cotter pin for a retaining pin. A foreign object on the face of the bolt during feeding. Incorrect primer depth on a hand loaded cartridge. Cook off due to a hot chamber. Firing the rifle without the cam pin. Of course, experienced riflemen will never encounter these problems, but they are possible.

[roklok]

I can see that it could be possible with seriously out of spec parts.

A couple points. The retaining pin for the firing pin limits rearward travel, not forward travel. That should not affect the ability of a rifle to fire out of battery one way or another.

A high primer still would not negate the fact that the bolt has to be locked before firing pin protrudes. Unless the high primer detonates from bolt face slamming into it. I find that unlikely, but may be possible.

Leaving out the Cam pin ? That could spell disaster, I am sure.

EDIT: Just found this :http://www.thehighroad.org/archive/i....html&amp&

[Mrgunsngear]

I worked on an M16/M4 qualification range for a couple years and never saw this happen. I saw just about every malfunction you can imagine (and even saw some that I couldn't imagine...). I think Matt Mc brings up a couple ways it could happen but the probability is sooo slim. In the years I worked there, at least 200 days a year units were firing, each unit with 150-250 firers, a minimum of 60 rounds/soldier (usually more than 200 rounds/soldier though). Do the math, that's a lot of rounds with 0 kabooms.

That leads me to think that ammo is the more likely issue. Obviously military ammo is made to a basic spec standard while some off the shelf ammo isn't. That's my $.02...

[Rifleman1776]

The "why" or "how" is unimportant. A friend of mine was recently given a felony conviction for owning an illegal machine gun. The AR (semi-auto) target rifle had been in storage since 1994. When fired the first time it cooked off two rounds. Subsequent tests by the ATF and FBI revealed it barely functioned at all and it never again fired more than one round on a trigger pull. Nevertheless he was still convicted.
Get yer gun checked and cleaned.

[Bartholomew Roberts]

A high primer still would not negate the fact that the bolt has to be locked before firing pin protrudes. Unless the high primer detonates from bolt face slamming into it. I find that unlikely, but may be possible.

It has happened. As unlikely as it may be ARs are popular rifles that see many more rounds fired through them than traditional rifles, so even a bizarre one in a million type accident will showup eventually.

[BPowderkeg]

AR-15 in .223 Rem/5.56mm NATO ??? i doubt it.........., but !!

i have had several .22 rimfires fire out of battery in conversions and dedicated uppers a formerly owned Colt .22 rifle was famous for firing out of battery !!

Based on the legendary original Colt M4, this .22 Long Rifle carbine sports German quality & craftsmanship.

BULLSIHET !!!!!! the Colt .22 version is the biggest F.U. since they discontinued the Python !!!!!!!

[madcratebuilder]

AR15 out of battery fire not possible, slam fire yes. The .308 AR platform is more prone to slam fires because of the firing pin weight. ArmaLite adds a spring to the firing pin to help prevent slam fires.

The "why" or "how" is unimportant. A friend of mine was recently given a felony conviction for owning an illegal machine gun. The AR (semi-auto) target rifle had been in storage since 1994. When fired the first time it cooked off two rounds. Subsequent tests by the ATF and FBI revealed it barely functioned at all and it never again fired more than one round on a trigger pull. Nevertheless he was still convicted.
Get yer gun checked and cleaned.

Wait a minute, I have to raise the BS flag. A rifle doubling one time well not have the atfe down your neck, "unless" you are being targeted for "other" activity.

AR's double all the time, worn FCG's are very common.

[Matt Mc]

The function of this part is to prevent the firing pin from falling out the rear of the bolt carrier assembly. What if it's just a cotter pin? What if the pin fails and pinches against the firing pin and holds it forward? It was this failure that I was referring to. This, in conjunction with worn or even missing ejector spring would cause immediate detonation upon chambering.

[Matt Mc]

Modern primers are pretty safe, but part of their correct function involves being completely seated in the primer pocket. Reloading military brass without correctly removing the crimp that exists around the primer pocket can cause incorrect depth, and can mangle one side and cause the anvil to move out of place. It is possible that a strike anywhere on the bottom of a damaged primer can cause it to detonate while it is still in the magazine.

[HiBC]

In the book "Black Rifle 2",iirc,they show a pic of some very high round count fuul auto AR with a broken cam pin.I do not own the book,and it has been some time since I looked.

The point was a broken cam pin can eventually happen,and cause firing out of battery.

I only have semi-auto bcg's.I'm not sure about M-16 bcg's,but on my bolt carriers,if the bolt carrier is not fully forward,the hammer will hit the bcg,not the firing pin.

[Mike38]

The "why" or "how" is unimportant. A friend of mine was recently given a felony conviction for owning an illegal machine gun. The AR (semi-auto) target rifle had been in storage since 1994. When fired the first time it cooked off two rounds. Subsequent tests by the ATF and FBI revealed it barely functioned at all and it never again fired more than one round on a trigger pull. Nevertheless he was still convicted.
Get yer gun checked and cleaned.

There has to be more to this story then what is being told. Did the owner immediately stop shooting and sought repairs? Or did he play with it at the range numerous times, drawing attention to himself? I find it hard to believe the BATFE would arrest and a court would convict someone that owned a rifle that doubled one time. I’ve seen a few firearms go full auto. Normally a person puts it away (after cleaning out their underwear) and gets it repaired. Heck, it even happened to me once. A semi auto .22 target pistol I own emptied itself on one pull of the trigger. A dozen or more people saw it happen. I put it away, had it repaired the next day, no visits from a government agent or anything.

[roklok]

Ok, so we can all agree....for a rotary bolt AR-15 or AR-10 to fire out of battery (without the bolt locked) it must have already had a SERIOUS mechanical issue, or the primer is being detonated by something other than the firing pin ?

[BPowderkeg]

What if it's just a cotter pin?

never, NEVER, NEVER ever use an ordinary cotter pin !! the one in an AR BCG may look like one, but it is a heat treaded special metal, personally i use the "old style" original solid pin in my regular shooters.

[Skadoosh]

A friend of mine was recently given a felony conviction for owning an illegal machine gun.

Mike38, you read my mind. I read Rifleman's post and was about to hit the reply button when I read your post. There has to be more to that story...much more.

[HKGuns]

I call BS on the felony conviction for doubling as well. It isn't against the law to have a poorly functioning / maintained rifle.

[Skadoosh]

It isn't against the law to have a poorly functioning / maintained rifle.

Ummm, it is when it becomes full-auto.

[Gunplummer]

I was stationed in Germany and working in a small arms repair/rework shop. A rifle was brought in that had caused an accident. The shooter had taken some brass in the face when he fired the rifle. (The guy was left- handed) That is all we were told. The rifle was still functional and did not appear damaged, but was extremely dirty. There was hard packed carbon through out the bolt and carrier. I could not say what had caused the accident, but it was chalked up as a dirty rifle by the civilian tech. He had no experience with M-16's, but had to report something. To get a load of shattered brass in the face it would seem that the rifle had to be out of battery. Strange things happen.

[greeniron]

RIFLEMAN1776, "The "why" or "how" is unimportant. A friend of mine was recently given a felony conviction for owning an illegal machine gun. The AR (semi-auto) target rifle had been in storage since 1994. When fired the first time it cooked off two rounds. Subsequent tests by the ATF and FBI revealed it barely functioned at all and it never again fired more than one round on a trigger pull. Nevertheless he was still convicted.
Get yer gun checked and cleaned. "

I had the same thing happen with my M4 a few months ago. The gun had barely 300 rnds through it over the time span of 4 months. Then one day I was at the range with my wife and I shot a few rounds as she watched. Then it happened, first a 2 shot burst then a 3 shot burst. At that point I asked Lisa to turn her camera on. I went through the whole mag on full auto. Never once took my finger off the trigger.
It was not bump firing as I was shooting from a bench off a bipod. So after we were done shooting I sent the video to the firearms store I bought it from, he viewed the video while on the phone with me. His response was "holy s$%t get that back here ASAP thats not supposed to happen.
It was sent back to the MFG and I got it back 2 weeks later. The only note was that they replaced the hammer and could not reproduce the full auto after replacement. I am not a gunsmith, I can take my firearms apart to clean them and thats it. I have no idea and no interest in what goes into making a semi a full auto, but it seems it takes a lot more than a hammer replacement. If I can figure out how to put up the video I will. After that happened I wondered what would the turnout have been if there was a LEO or ATF agent at the range that day. I now keep the repair paper work in the gun case when I go to the range.
Lessons learned,
1. Always know your firearm
2. Always be in control of your firearm when the SHTF with it.
3. Never wonder why it happened just get it fixed for safety and legal reasons.
4. Dam that thing was accurate at 75 yrds on full auto, 3" shot grouping
5. It takes about 4 seconds to blow through $12.00 of ammo
6. Man was it cool firing a full auto at least once, 1 item off my bucket list
7. Smiling for more than 1 hour straight hurts real bad after.

[Slamfire]

Well I believe if the cam pin were to break and the firing pin stuck out of the face of the bolt, you could have something similar to advanced ignition.

Unless something is really out of tolerance, an AR15 firing pin is retracted until cam down. However, in the book Black Rifle, there is a section on the redesign of the M16 firing pins, and it says the rifle slamfired, rifle damaged and that Marines were injured. I got the impression that out of battery incidents were going on.

The Army had to redesign the firing pin by making it lighter. There is a Stoner quote in the book Black rifle, he said there are three things to make a rifle less likely to slamfire: Lighten the firing pin, thicker primer cup, less sensitive priming compound.

As for in battery slamfires, back in the nineties you could not convince anyone that AR15's would slamfire at all. Back then the only allowed explanation for slamfires was “high primers”. It was a truism that only high primers caused slamfires and that there was no such thing as a sensitive primer. Primers were primers. All round and shiny and all the same.

Times have changed.

In fact it is very difficult to get a high primer to slamfire. Wayne Faatz ran experiments in his M1 Garand, trying to figure his slamfire in that rifle. This became an article in American Rifleman. He only got consistent slamfires with high pistol primers after he put a flattened primer anvil under the pistol primer. Primers that were high, no anvil underneath, rifle and pistol, the bolt face just seated without any ignition.

People in the highpower community have witnessed or had in battery slamfires so the skepticism is slowly going from the sport. But there are some exceptionally stupid ones who hold to the dogma that primer sensitivity has nothing to do with slamfires.

I had one in battery slamfire with the new, brass finish, more sensitive WSR. Put a round in the chamber and dropped the bolt. The rifle discharged into the dirt. My scorer, a bud of mine, when he got up, his rifle discharged. He was using Fed 205M. I talked to him yesterday and asked if he had any more slamfires in his AR15, and he had. He had one more with Fed 205M, in the standing stage, and that was the last he was ever going to use Federals in his AR15’s. He also told me he now rode the bolt down. I also changed my loading procedure standing, I lower the bolt half way and let it go.

I have been looking for years for an reputable account of an out of battery slamfire in a AR mechanism, have not heard one yet.

Lots of in battery slamfires.

[Mike38]

It isn't against the law to have a poorly functioning / maintained rifle.

Ummm, it is when it becomes full-auto.

I respectfully disagree.

If you continue shooting it, playing Rambo, showing off to all your friends, then yes, it would be against the law. If you put it away immediately, and seek repairs as soon as possible, no one from the BATFE is going to arrest you for it.

I’ve seen M1911’s go full auto during Hardball Match competition. That is a scary sight to behold. Allmost always leaves at least one hole in the awning above the firing line. Law Enforcement and active military were present when it happened. No one said a word about legality. They were more concerned about the shooter then anything else. They commended the shooter for executing excellent control (no new holes in the awning). One of the deputies even volunteered his smithing services free of charge.

It happens. It only becomes illegal if the shooter lets it.

[Skadoosh]

I respectfully disagree.

If you continue shooting it, playing Rambo, showing off to all your friends, then yes, it would be against the law. If you put it away immediately, and seek repairs as soon as possible, no one from the BATFE is going to arrest you for it.

Disagree all you want, but technically, a non-class III firearm becomes illegal the instant it becomes full-auto.

Whether the owner is guilty of a crime depends entirely on what the owner does to correct the promblem...especially how quickly.