AR-15 Upper Explodes on Camp Pendleton

[LiferLance]

"Longrifle" the Camp Pendleton range control just released a widest dissemination letter Regarding a range accident today.
At 0833 today while conducting BZO a Marine's rifle exploded on the 9th shot of the day. Initial investigation leads to possible double charged ammo as the cause. All ammo is Federal 5.56 green tip, with the shooter using 2 separate lots. The round blew the whole front off of the rifle and only the Marine's safety glasses kept him from loading an eye.
Be careful out there and I'll add lot numbers and positive case when it comes up!

[wild_weasel]

There is not room for a double charge of powder in the M855 round.

[AK all day]

Sounds like an out of battery detonation.

[opie4386]

Yeah....um double charge? Not really a problem with M855

[m16]

Reminds me of this:

Link

[m35a2]

Maybe a squib round?

Looks like there is still threads on the upper. Maybe the barrel nut backed off?

[Gutz]

Maybe a squib round?

Looks like there is still threads on the upper. Maybe the barrel nut backed off?

That's too clean of a break.... Maybe it was loose? Look at that salty rifle!

[Josh3239]

They explained it in the picture, that clean of a break is clearly a barrel nut issue. But that isn't the picture of the rifle the OP is describing.

There is not room for a double charge of powder in the M855 round.

This.

Sounds like an out of battery detonation.

Not possible.

[Sergius]

Possible cause could have been a squib round that got stuck in the barrel, next round was chambered, shot, and blew the upper receiver. Happened to me. Good thing I caught it before I pulled the trigger.

[LiferLance]

AR-15 Upper Explodes on Camp Pendleton

That guys Army. Ours blew the **** up. Also, the gun that blew up today was an A4, that's an M4.

[CK_32]

Do you know what unit? I'll see if the Marine detachment at my work heard anything about it.

[Michael Ehline]

We sued M-16's when I was in. When were they issued AR-15's?

[lwhennen]

They don't lol Its all M4's and M16's.

[SocomM4]

The one pic, the guy made an ar15 takedown that's held together with 550, lol.

[Army]

Not possible.

Quite possible.

If the sear had worn and no longer stopped the hammer, and the disconnect/spring was crapped out, the hammer can easily follow the BCG forward, creating a fixed firing pin situation. Enough hesitation of the round being chambered, will have the pin already resting on the primer. More than possible to detonate before the bolt can rotate and lock.

Saw it happen twice to m16's. Three times with poorly maintained AR's.