Guns are dangerous. Federal AE223BK Kaboom.

[Lostinthewoods]

Out of Battery discharges are almost impossible on the AR. The firing pin is not capable of touching the primer until the bolt is fully locked up.

I won't say it's completely impossible, but it's very close. There'd have to be some sort of other factor involved... debris or a improperly seated primer, etc.

It IS an OOB discharge, I've seen it when the hammer follows the bolt home and strikes the FP right before the bolt lugs have locked up.

Way back in the day, I have SEEN (I've of course never done or condone anything like this) people used to remove the disconnector from their shorty's (only light buffers) and stick in a FA safety to make the gun's shoot FA, very dangerous, as the hammer was just following the bolt home and conditions happened VERY often that made the exact same thing as the OP's condition happen.

Look at the case head, there is NO WAY to swell that head up like that UNLESS THE CASE WAS NOT FULLY IN THE CHAMBER WHEN IT WENT OFF....PERIOD.

Explain ANY other way for that pressure ring (directly in front of the extractor groove on the pic of the broken case head) to get there, and I will quit arguing and shut up.

It may not be a FCG problem, but some way that round went off without being fully seated with the locking lugs locked.

HB

EDITED to ADD: If something happened that suddenly increased headspace by 1/8" or so, say the bbl slipped forward in the bbl extension, this could make it happen, but I don't believe that is the case, as I believe it would be very obvious.

[markm]

Yes. I agree on your scenario of the hammer following the carrier home and creating FA fire.

But.... it is mechanically Impossible for the firing pin to touch the primer until the bolt is locked and in battery. You can pull a bolt group out of an AR and confirm this by pushing on the back of the firing pin. The front of the firing pin can't even protrude through the bolt face until the bolt is locked up.

It's not even debateable. It's mechanically impossible on an in spec AR rifle. Now if you had an out of spec firing pin or some thing way out of the norm it could happen, but the firing pin would have to be pretty significantly out of spec. Now if a hunk of debris or popped primer somehow got in the bolt face I could see how that might ignite a round out of battery. That's a pretty long shot though.

[Remy]

Lake City XM193 has the heat marking where the brass necks down, at least all the Federal XM193 and white box Lake City XM193 I have does. Why does that not have the typical heat discolor I'm used to seeing?

Just to admit, I do not know what the heat mark is from or why it is there, I just know I see it evertime I open my ammo. When I look at the picture a few posts up, I instantly noticed that the brass is a constant color and not the same as what I am used to holding/seeing.

Larry

Larry,

To my knowledge, the discoloration of the shoulder/neck on military 5.56mm ammo is result of "annealing" the brass in that area during the production process. And yes, it is normal to see most commercial .223 WITHOUT the annealing color present.

The rounds shown in the photo, ARE NOT Federal XM193 in my opinion. I have seen quite a few examples of the XM193 cartridges, and they always show evidence of annealing.

On the head stamp they normally show the "LC" for Lake City and then two digits indicating year of production. Some of the XM193 ammo will also be stamped with the NATO figure on the head stamp in addition to the info I already mentioned.

Something is fishy with this batch of ammo.

[markm]

The rounds shown in the photo, ARE NOT Federal XM193 in my opinion. I have seen quite a few examples of the XM193 cartridges, and they always show evidence of annealing.

And that is a SPEC REQUIREMENT for XM193....

http://www.federalpremium.com/resources/xm193.aspx

Although so is case neck sealant, and I've pulled bullets with no case neck sealant on them.

[FromMyColdDeadHand]

It IS an OOB discharge, I've seen it when the hammer follows the bolt home and strikes the FP right before the bolt lugs have locked up.

From the OP:

"I was on approximately round 20-23 of a full 30 round magazine, and I pulled the trigger and felt an extreme GUSH of air on my chest/abdomen/legs. The magazine was literally SHOT out of my magwell, and the bolt was stuck."

Derek didn't report a double and it doesn't seem he was running rounds thru the gun. For what you say to happen, the first round he squeezed off went OK, but the second round had your failure? That is outside of the bolt lock/clearance issue mentioned by markm. Don't know Derek personally, but I've watched him shoot alot I'd think he'd be able to report a double.

[Lostinthewoods]

Yes. I agree on your scenario of the hammer following the carrier home and creating FA fire.

But.... it is mechanically Impossible for the firing pin to touch the primer until the bolt is locked and in battery. You can pull a bolt group out of an AR and confirm this by pushing on the back of the firing pin. The front of the firing pin can't even protrude through the bolt face until the bolt is locked up.

It's not even debateable. It's mechanically impossible on an in spec AR rifle. Now if you had an out of spec firing pin or some thing way out of the norm it could happen, but the firing pin would have to be pretty significantly out of spec. Now if a hunk of debris or popped primer somehow got in the bolt face I could see how that might ignite a round out of battery. That's a pretty long shot though.

I agree that the FP cannot contact the primer until the bolt is CLOSE to home , but the lugs do not have to be 100% turned and locked, only close, enough that maybe only 20% of the lugs are in engagement. A dirty chamber or bent round would exasperate the problem. Enough that the bolt could possibly not lock 100% and allow the pressure to blow the assy back, I agree some other factors would have to be out of spec for this to occur.

Both times I have seen this was on weapons with high round counts. Looking at his bolt carrier in the pics, it looks pretty rough, maybe the cam key hole is slightly worn, or tolerance stacking is allowing some problem to occur.

I don't know WHAT caused it, that is NOT what I am arguing, I am arguing that it IS an OOB discharge, whatever the cause.

NOT AN AMMO PROBLEM

Explain to me ANY scenario where that pressure ring can occur with the case being fully seated in the chamber and you will convince me otherwise. (Except the extreme headspace example I cited above)

HB

[markm]

Explain to me ANY scenario where that pressure ring can occur with the case being fully seated in the chamber and you will convince me otherwise.

I hear ya. But I can't see the pics here at work. They're filtered. I'll try to remember to check them out a the house. I'm dying to see what the ammo looks like as well.

[Lostinthewoods]

I hear ya. But I can't see the pics here at work. They're filtered. I'll try to remember to check them out a the house. I'm dying to see what the ammo looks like as well.

I didn't realize you hadn't seen the pics, it is evident when you see them.

There is nothing wrong with the ammo, it is just the cheap .223 FC commercial stuff in 1000 round bulk pack, it even says on the box "1 box of 1000" not 20 boxes of 50 like normal.

I guess it is POSSIBLE, but very unlikely, that someone put some very nice reloads (and even slightly dinged them up, like factory stuff) with perfect crimps and all the same headstamp in a box and sold them, but I believe it's all typical internet drama.

I hope I can buy 10K rounds of it CHEAP from someone because it is so bad!!

If they were passed off as mil-spec 5.56, then that was wrong.

HB

[dookie1481]

Derek,

Glad to hear you are ok.

As someone with 10+ years of reloading experience and lots and lots of that with 223 I'd have to say from what I see on the picture of the ammo that you posted is reloaded ammo.

In that picture I count 5 different rounds with case dings on the body. Those dings are all classic ejection dings.

I'd suggest inspecting any of that you have left and looking closely at the cases and check for dents, I'd bet you see more of them.

Semper Fi

Interesting, I've seen Q3131 with dings in the casing...are these used cases as well?

Jay

[Derek_Connor]

Getting ahold of a live person @ Federal has been unsuccessful today.

From my limited reseach and talking to people offline, and sending the upper to a competent smith, it seems the diagnosis is a simple case failure.

Not an OOB, not bullet set back, not over pressure, not even a real kaboom.

Will update whenever I get ahold of federal