AR-Kaboom

[Cynical]

My church security team were training Sat. and we all brought some rifles to break up the training. One of our guys had a kaboom in his ar. The magazine catch blew out the side and was hanging down due to gravity I’m assuming. I asked if it was a factory load or handload and he said all he he shoots is factory ammo. After I asked a few more questions he said that it’s happened on 3 other rifles. I was ruling out bad ammo on 3 different rifles. The one thing I noticed as I was standing behind him was that he was holding the rifle at the magwell. I don’t believe in coincidences so I decided if he’s holding the rifle at the same way is it a causal factor. My question is, would pressure on the bolt catch slow the bolt down enough to cause an out of battery fire. FYI it’s the first time I’ve ever seen it and he was lucky, a little powder burn on the heel of his hand, and the round in the mag was trashed. I kinda know the process of how an ar works but wasn’t sure about pressure on the bolt catch and mag because he was using it as a rest. I’ve built 5 ars (yeah I know, is that all), I’ve never had a problem out of mine. If I remember the rifle he was using was a Sig diamondback? I’m just not seeing the same problem happening with 4 rifles and factory ammo. Any thoughts?

 

[d.kaufman]

Any thoughts?

What brand is the "factory ammo"? Any pics of the damage to the rifle? Running 223 or 556? Much more info needed, but if this happened to the same guy 4 times and wasn't hurt, I'd say he either needs to buy lottery tickets or stay away from the AR platf

 

[Cynical]

What brand is the "factory ammo"? Any pics of the damage to the rifle? Running 223 or 556? Much more info needed, but if this happened to the same guy 4 times and wasn't hurt, I'd say he either needs to buy lottery tickets or stay away from the AR platf

I don’t have pics unfortunately but the cam pin was busted and the bolt was slid back a bit so I told the”range expert” to take the hand guard off and remove the barrel and everything would come apart. The head of the case was gone and the rest is stuck in the chamber. The ammo for Sat. was American Eagle, I think its made by Federal but I’m obviously no expert. I messed around with a couple of my ar-s trying to slow the bolt down to mimic an out of battery ignition but couldn’t nail it down. I’m just sayin the same problem in 4 different rifles isn’t adding up to me.

 

[Cynical]

What brand is the "factory ammo"? Any pics of the damage to the rifle? Running 223 or 556? Much more info needed, but if this happened to the same guy 4 times and wasn't hurt, I'd say he either needs to buy lottery tickets or stay away from the AR platf

Ammo was .223

 

[d.kaufman]

I’m just sayin the same problem in 4 different rifles isn’t adding up to me.

It's not for me either. That's why the couple questions I asked

 

[Cynical]

It's not for me either. That's why the couple questions I asked

He even had powder burns on his hand where the magazine catch blew out the side. I was trying to put downward pressure on the mag as well on the bolt catch on my rifles to try to stop or slow the bolt down. Even then when is the bolt far enough along to engage the firing pin. I’m trying to figure out how this could happen because I don’t believe he’s lying.

 

[dieselrealtor]

Has he run a 22lr conversion in his rifles?

 

[Ark]

The only relevant question is "does he own a .300BLK?".

 

[AndreusMaximus]

Has he run a 22lr conversion in his rifles?

I'm assuming where you're going with this is that 22lr can cause lead buildup in the barrel, which could cause a spike in pressure, right?

The only relevant question is "does he own a .300BLK?".

Maybe. The failure doesn't sounds quite catastrophic enough for that, though. Should be pretty easy to determine whether or not there's a .30 cal projectile lodged in the throat, if OP is able to have another look at it, though.

 

[Wolfhound]

I am wondering if he is leaving cleaning patches or other material in the chamber or barrel.

The part about removing the hand guard to get to the barrel is a little confusing. Did they pull the gas tube also and use a barrel wrench to remove the barrel for some reason? Or are we just taking about separating the upper and lower receiver?

 

[dieselrealtor]

I'm assuming where you're going with this is that 22lr can cause lead buildup in the barrel, which could cause a spike in pressure, right?

That is the first thing that comes to mind right now, multiple rifles rules out everything except user error.

 

[Cynical]

Has he run a 22lr conversion in his rifles?

I don’t think so because he brought an MP 15-22

 

[Cynical]

The only relevant question is "does he own a .300BLK?".

Not that I know of.

 

[Cynical]

I am wondering if he is leaving cleaning patches or other material in the chamber or barrel.

The part about removing the hand guard to get to the barrel is a little confusing. Did they pull the gas tube also and use a barrel wrench to remove the barrel for some reason? Or are we just taking about separating the upper and lower receiver?

He had shot a full mag previous to the kaboom.i told them to remove the hand guard and barrel so the upper and lower could be separated as the bolt was frozen about 1/4- 1/2 inch out of battery.

 

[Cynical]

That is the first thing that comes to mind right now, multiple rifles rules out everything except user error.

Which is why I was wondering if applying downward pressure on the magazine and hand on the bolt catch would it slow the bolt down enough that a quick follow up shot would be susceptible to firing out of battery. 4 times with factory ammo and factory rifles doesn’t add up to me. Just curious as to what user error would cause that.

 

[DoggyDaddy]

Which is why I was wondering if applying downward pressure on the magazine and hand on the bolt catch

I guess my question would be, why on earth would anyone do that? That sounds like a really awkward way to hold/shoot the rifle to me.

 

[Cynical]

I guess my question would be, why on earth would anyone do that? That sounds like a really awkward way to hold/shoot the rifle to me.

Don’t know, but that is the way he was holding the rifle. I’ve just never actually seen a kaboom and was literally standing behind him when it happened. Prolly never figure it out but thought here was the best resource for potential causal factors.

 

[DoggyDaddy]

Don’t know, but that is the way he was holding the rifle. I’ve just never actually seen a kaboom and was literally standing behind him when it happened. Prolly never figure it out but thought here was the best resource for potential causal factors.

I mean... it's got a pistol grip and a forearm for a reason. One for each hand.

 

[Cynical]

I mean... it's got a pistol grip and a forearm for a reason. One for each hand.

Lol, I know right. Depending on the handguard, price alone would be a good incentive to use it.

 

[2tonic]

If you know a lot of AR shooters, you probably still don't know 4 people that have had "kabooms", much less one guy who has had 4. Operator error at some level is indicated.
Maintenance / cleaning issues? Headspace correct?
Barrel properly torqued/aligned with barrel extension?
BCG assembled correctly?
Some behavior of his is the culprit IMO. I've seen shooters hold at the magwell before. Usually they claim to prefer the vertical orientation, similar to the pistol grip, but more likely they lack proper conditioning, and their arm gets heavy being held extended in front of them.
Regardless, I've never seen that technique, alone, cause a kaboom, but it could maybe, possibly be a contributing factor.
I don't think we're gonna know the answer to this, without a thorough post mortem, or until he has number 5.