Blew up my AR today. KABOOM!

[Whiskey Gulf]

Glad you weren't hurt. It will be interesting to see the pictures.

 

[coltseries70]

Syrian surplus ammo?

 

[Suputin]

No injuries. My left hand was numb for 1/2 hr and the adrenaline was crazy. Glad I was wearing Mechanix gloves and glasses.

It was a Norinco CQ. 14.5" bought this fall and Norinco white box ammo.
Loaded the mags at the range from the package. Brought the rifle out of the bag, chamber check, put in a pmag, pulled the charging handle hit the safety and let 'er rip.

Fourth shot into the first magazine and it happened.
Blew everything out the magwell and the bolt is stuck shut, no live ammo left in the chamber. What I can see of the bolt face and extractor are pretty messed up as well as the walls of the bolt carrier chamber. Did not blow apart the upper but distorted the metal. It is junk now. Lower seems okay.

Apparently this is rare and I am very lucky.
I am trying to narrow down what happened. The rifle was clean and oiled properly. Bolt group was assembled properly. Function check proved operation after cleaning. 4th round in makes me believe there was no barrel obstruction. Rifle will not fire if bolt does not lock up. Firing pin will not protrude unless bolt is locked up. Trigger group functions correctly. other ammo primers look okay.

Only conclusions I can figure are:
debris on bolt face such as broken extractor or broken locking lug?

Shell casing stuck in bolt face, bolt tried to load new shell, old casing struck primer of live round?

Bolt did not lock up properly due to debris in locking lugs?

Parts out of spec?

So either a failure to extract or a detonation out of battery is the result. Caused by my own stupidity or a total failure of rifle or ammunition.

I will post pics after I create a photo bucket account.

Has this happened to anyone else?
Does anyone have any ideas what happened?

Not what you apparently think. If you understood how the rifle works you would realize that none of your conclusions hold any water.

How is it possible for this to have been an out of battery explosion when by your description the bolt is still in the forward position? An out of battery explosion means the bolt was not locked shut which will always result in the BCG being blown backwards at high velocity. If the bolt is not locked then the rifle operates in blowback mode which will be a very violent event in a rifle caliber.

If the bolt is locked forward then there are only a few options. Either this was an obstructed bore or the wrong ammo or bad ammo. If the rifle fired the previous round and loaded the round that detonated on its own then it is unlikely to be an obstructed bore. If you are 100% certain it was the correct ammo then we are left with this being an ammo problem.

There are a number of potential causes which could result in the effects you have described. You will have to get the bolt out in order to figure it out.

 

[Gorno]

That is scary. Glad to hear you are ok. Being a lefty shooting right handed rifles, the thought of catastrophic failure right next to may face is quite a scary concept. I hope I don't ever have that misfortune. Please post pictures when you get a chance.

 

[Suputin]

Glad your ok.

To me the only way this can happen is a bore obstruction or a round went off prematurely possibly in the mag or when being cycled. Gases need to be trapped in order for things to go kaboom and blow up.

I see reading and comprehension is not a priority anymore. OP stated the bolt was in the forward position after the detonation. How could that be if a round had detonated during feed cycle?

Instantaneous pressure inside the case can reach 60,000 psi. That sounds like more than enough pressure to cause issues if something fails.

Stuck firing pin is my guess. If he was shooting the crimped tip Winchester white box (45gr 'varmint' stuff), I'd say pushed in bullet for sure.

Out of Battery.. if he recovered the brass it should be a lot easier to tell.

NOT OOB. OP stated bolt is in the forward position. Thus not a stuck firing pin.

There are other reasons for overpressure in a case than a pushed in bullet. There are other reasons a case could fail than overpressure.

 

[Suputin]

This type of thing is more often ammo than rifle. It's more likely that the case was too soft and failed. This happens, for example, when brass is annealed upside down.

The case head blows out. The weakest portion of the bolt face is the extractor which fails first is often bent into the locking recess along with brass from the case head.

The debris usually blows out the port and then the mag.

Pistol powder usually breaks the bottom of the carrier and often rips off the side of the upper.

Breech obstructions only do this if the obstruction is very close to the projectile. They also leave bulged barrels.

The simple way to tell is to place a rod in the barrel and tap the bolt rearward.

If there is no projectile in the barrel, the extractor will bend back and the bolt will move to the rear. The base of the case will be bulged out up to the last point of support and likely blown out at the extractor cut right back to the primer pocket.

FIVE pages in before we get the first person to actually understand what likely happened here and post a reasoned and intelligent response.

Well done sir. Shame on the rest of you.

"Bolt is stuck shot".
Is the bolt locked - i.e. - is the bolt rotated so that the locking lugs are engaged?
If so, there was a catastrophic case head failure, allowing high pressure gas to be released back into the receiver.
Now why did the case fail?

Another man to get it right. THIS is the most likely scenario. Case head failure.

 

[BenL]

What I can't understand is how on one hand can the "bolt be stuck shut" and on the other "What I can see of the bolt face and extractor"?

How can one see the bolt face and extractor while the bolt itself is stuck shut?

 

[tiriaq]

I have inspected a couple of rifles that were wrecked by casehead failures when the bolts were locked.
This incident very much sounds like this.
For whatever reason the pressure exceeded the capability of the cartridge case to contain it.

 

[Suputin]

That is scary. Glad to hear you are ok. Being a lefty shooting right handed rifles, the thought of catastrophic failure right next to may face is quite a scary concept. I hope I don't ever have that misfortune. Please post pictures when you get a chance.

I am also a lefty and have experienced a case head failure in an AR. In my case it was due to excess headspace in a wildcat cartridge. The failed case head blew out the extractor which jammed the bolt in the barrel extension tightly enough I had to pound it out with a large hammer. Luckily the round I was testing only held ca 18gr of powder so considerably less powerful than a 223. I did not get hit with any burning powder or brass shrapnel although the bang was gawdawful loud.

What I can't understand is how on one hand can the "bolt be stuck shut" and on the other "What I can see of the bolt face and extractor"?

How can one see the bolt face and extractor while the bolt itself is stuck shut?

He likely can't see the bolt face but the rear end of the extractor is visible when the bolt is locked up.

 

[mikethebike]

Syrian surplus ammo?

Humm i think they're not selling their surplus ammo anymore... Might not be qualified as "surplus" anymore...

 

[OccasionallyOnTarget]

Yikes

 

[jdman]

please post pics so the speculation stops, lol

 

[yodave]

please post pics so the speculation stops, lol

get the torches...........He is a shill............I just can't figure out whose product he is trying to endorse while dragging norinco through the coals..........

 

[HKMark23]

Originally Posted by HKMark23
Well, if CGN consensus means anything at all (it doesn't, just saying ), the problem must be with the OP's grip or stance or his cleaning products or something. It just can't be the Norc products,,,, nnoooo way ! Guys who spout nonsense like "you get what you pay for" are just brand snob suckers with more money than brains. Its common knowledge .

Yes, but how do we explain all the other non-norinco Kabooms? Counterfeits from Norinco? or are they secretly swapping parts somewhere in the supply chain?

Never let a good consensus die !

 

[mildcustom2]

I see reading and comprehension is not a priority anymore.

And I see in typical Canadian firearm owner fashion insulting people amongst your own is a bigger priority than having a discussion.

No wonder politicians walk all over us with gun control laws. Firearm owners are too busy starting fights amongst themselves instead of working together.

 

[chunkydrunky]

From the OP, Case head separation or obstructed bore is my newbie guess. I'm new but I have a engineering degree. Pics might help. Either way, glad you are ok OP. I've been using the norc 556, the ammo is ####, weak brass, out of spec brass, 1 grain differences in powder weights, blown primers, I only have 200 rounds left from half a case. I never buy it again, brass is too ####ty to even reload. Cheap price is good. Cheap product not so much!

 

[Beater]

ive had the misfortune of having this happen to me aswell a few years ago. Winchester whitebox and a eagle arms rifle. overloaded round. split the receiver, blew the mag apart, welded the casehead to the bolt. took some real work to get it apart for inspection

 

[Kryogen]

Am I the only one who has not had a catastrophic ammo failure yet?

 

[Rust]

I get home from work and I have 8 pages of replies! I have not read through them yet because I want to get pics up.

 

[Runningfool]

Thanks for posting pics.