Round "cooking off" in the magazine?

[markm]

It didn’t.


The AR can not fire out of battery.

Thanks for squashing that. I hate that myth.

Sounds like a small kaboom... that could easily appear to be a mag cook off to an RO. They don't get that job for being the sharpest tool in the shed.

[TomMcC]

Did the shooter and RO find the round fired just before the alleged cook off? Probably just a typical blown case.

As for an OOB firing, isn't it impossible for the firing pin to protrude far enough to reach the primer until the bolt is locked?

[BC98]

If the bolt is out of spec or the headspace is improperly set, an OOB detonation is completely possible resulting in a case head separation, blowing out the magazine and (sometimes) destroying the upper reciever. I have seen it happen.

The firing pin doesn't protrude enough from the bolt face until the bolt locks into battery to ignite a primer.

[Rifleman_04]

If the bolt is out of spec or the headspace is improperly set, an OOB detonation is completely possible resulting in a case head separation, blowing out the magazine and (sometimes) destroying the upper reciever. I have seen it happen.

No. Not with the AR/M16 FoW. Not possible.

What you sawr was a ruptured case head. Happens a lot with worn brass and crappy reloads.

[1168]

Thanks for the con-ed, guys. I’ve heard of OOB’s in this weapon type but never saw one in person. Makes sense that OOB would be highly unlikely in this platform.

[Rifleman_04]

The firing pin doesn't protrude enough from the bolt face until the bolt locks into battery to ignite a primer.

Also the hammer can’t make contact with the head of the firing pin when it’s out of battery.

[AKDoug]

My comment was a bait cast.. thanks for making my point without me having to be a dick..

[100]

serious amount of lead down range in short order to get to cook off territory. I wouldn't think that a cook off from an M-16 type weapon would be all that bad because
1. It's a closed bolt weapon and
2. It's not belt fed. (far less chance of run away if you have a malfunction you can't clear) Just take the mag out keep the weapon pointed in a safe direction. For us, we wait 3-5 seconds but only have 10 to clear it.

[TomMcC]

Not a cook off in the chamber...but...in the mag. Or set off by a sharp pointy thing in the mag. It's pretty unanimous that it was a blown case.

[ryder021970]

So I was able to track down the fellow who had this incident. He said that the round in the chamber didn't cook off; one of the rounds in the mag went off. He said that shell casing has a gash about 1/8 inch long perpendicular to the extraction groove. He said it was a reloaded round.

It looks like they've reloaded that shell one too many times.