Hey everyone,

The other day at work we had one of our Bushmaster rifles had a little kaboom.  As for the details of what happened, I can only tell you what I was told as I was not there to see it happen.  

During qualifications, two people used the rifle with no issues.  The third guy shot a couple rounds in semi and then switched to FA.  I think he was firing from the hip (like a knucklehead eventhough it probably saved him from worse injuries) when the kaboom happened.  He said about four rounds went off with no problem and he did not hear anything strange prior to the incident.  

The damage is shown in the photos.  Sorry for the lower and magazine photos, I only had a few minutes to photograph everything and I could not take them out of the bags.  

The damage to the lower consists of the magazine release was broken and blown out from the left side.  The bolt release was also broken and blown out.  The magazine well was bowed slightly.  There rest of the damage is self explanatory.  There may be a round in the chamber but I am not sure.  

As for the guy that was shooting, he only had some small powder burns and very little shrapnel in his hand.  

As for maintenance, who the hell knows as it is in the car and I doubt anyone takes the time to look after it on a regular basis.  (Thank god my rifle is issued to me and I have complete control of it).  What do you all think could have happened.  

Here are the pics.

Oh yeah, sorry for the crappy cell phone pictures!

ETA:  the ammunition that was being used was I believe factory loaded XM193 on stripper clips.  Lake city brass from 2009.

My money's on a squib round that lodged in the bore past the gas port, & cycled the action for the next round to go off full auto.  Tough bbl.  Might be a bulge in it past the gas port.  Anyone count the rounds in the target?

If I'm wrong, I'll buy a doughnut for anyone in the D/FW area that contacts me to 'splain what really happened.

Merry Christmaunukah!

backbencher

PS - OR - that wasn't a 5.56mm bullet that tried to go down the bore.  Heard of a 6.5 Jap that had the chamber bored out to accept a .30-06 case.  It shot .30-06 @ some incredible velocities - b/c the owner didn't know he had a 6.5-'06...

I had my FA Uzi destroyed on me from a squib load as well.....

Transferable FA lowers are expensive (not sure if that one is a transferable or post sample).  Based on the appearance of this one, is that something that could be repaired?

The bolt isnt locked, so it could have been an OOB. Squib is a possibility like everyone has said too.

Odd that the carrier took more of a beating than the bolt or extractor.

Anyway, a squib that somehow makes it past the gas port before lodging (and I doubt this happened) will not have generated enough pressure to cycle the carrier.  Sorry to have to say this (I mean no offense) but the fact that the shooter was horsing around raises a suspicion he might also have manually cycled after a squib or misfire failing to note what did not eject.

If the story is accurate an ammo-related problem of some type seems likely.  To get an OOB low-pressure KB you likely invoke a high primer and reloaded ammo.  Other ammo-related problems such as excess pressure, incorrect powder burn rate, incorrect primer, metallurgical brass failure from reverse annealing, headspace problem (5.56 in .223 or failure to trim excessively long brass) involve a closed bolt.  

An unlocked bolt seen after a KB does not allow us to certify failure to lock at time of discharge.  Carrier didn't move back much, so I'd want to know whether the hammer was found resting on the pin vs still cocked and retained by the autosear notch.  Probably nobody thought to check.

Sam

There is likely what's left of a cartridge case in the chamber, but definitely not a live round, any longer.

Is this a dept. post-may gun, or a personal transferrable?

He said qualifications, so I'm guessing (hoping) that this was a postie.  That said, most of the damage appears to be restricted to the upper.  (Thank God!)  

...unless I'm missing something in the shot of the lower..?

Mike

OP said magwell is bowed.

That's a relatively simple fix with the right C2 on board.

Mike

Sorry everyone for the late reply.  The rifle is a department gun and it is about 10 or so years old.  I do not know how much it was messed with prior to me taking the pictures.  They may have tried pulling on the charging handle and what not, but I have not been told. We do not have a department armorer for the AR platform so sadly most guys have no idea what they are doing when it comes to these rifles.  

I did not want to look down the barrel to see if there was a round still in the barrel or chamber.  If I am ever told what came about with this I will let you all know.  Who knows if they will tell me anything.     Thanks for all the replies.