View Full Version : Colt M16A2 Commando KABOOM
larry starling
05-17-13, 05:53
Some interesting pics. Thought I would share.
http://www.thefirearmblog.com/blog/2013/05/16/colt-m16a2-commando-kaboom/
Ouch! Hopefully, the operator was ok.
davidjinks
05-17-13, 06:59
I'm wondering what type of ammo they were using.
That is...just wow.
That gun looks like it's seen some use.
They noted that the gun possibly fired while out of battery. In a previous kaboom thread, I seem to recall reading that it was impossible for an AR to fire while out of battery along with a pretty definitive explanation. Did I misunderstand, or was the information just wrong? Is it possible for an AR to fire out of battery?
polymorpheous
05-17-13, 09:58
That gun looks like it's seen some use.
They noted that the gun possibly fired while out of battery. In a previous kaboom thread, I seem to recall reading that it was impossible for an AR to fire while out of battery along with a pretty definitive explanation. Did I misunderstand, or was the information just wrong? Is it possible for an AR to fire out of battery?
The bolt needs to be locked in order for the firing pin to protrude enough to fire a round.
The bolt can't lock until the can pin reaches the clearance cut in it's channel in the upper.
Firing out of battery can't happen.
That right there is why I don't like bullpups.
Sent from my iPhone on tapatalk
The bolt needs to be locked in order for the firing pin to protrude enough to fire a round.
The bolt can't lock until the can pin reaches the clearance cut in it's channel in the upper.
Firing out of battery can't happen.
Ok this was the way I understood it as well, but I wanted to make sure I had an accurate grasp on how the rifle went together and functioned. Thanks very much for the explanation.
I wonder how the Tavor would handle that. Also, this is why we wear glasses.
Nothing is impervious to an overcharged round, or a squib that somebody fired another round behind.
I had something like this almost happen to me back in 1990 with a brand new Bushie Carbine. Praise the Father, I checked the barrel after the last round out sounded kinda weird. She was blocked, with a pill stuck half way down the tube! Think I'll pass on the bullpup craze, thank you very much!
Firing out of battery can't happen.
..unless the firing pin is stuck forward.
The bolt has to move rearward for the firing pin to be able to reach the round.
Heavy Metal
05-17-13, 17:41
..unless the firing pin is stuck forward.
That can't happen on an M-16 series rifle.
DIRTMAN556
05-17-13, 20:35
That is pretty scary. I dislike it when we see images like these but no resolve as to why it happened.
RearwardAssist
05-17-13, 20:36
I doubt it was an overcharged round cases fill almost to capacity on the 223 and unless it was pistol powder I dont see that happening.
vicious_cb
05-17-13, 23:28
Brazilian gun firing brazilian 3rd world garbage ammo perhaps.
I'll go with bore obstruction....
Reminds me of this vid of an M&P 15 Sport coming apart
http://www.youtube.com/watch?v=qoZnCxqa4QA
http://www.youtube.com/watch?v=HIuTVfl8G2U
That can't happen on an M-16 series rifle.
Who knows, maybe the front .50" of the firing pin was broken off and protruding, "slam-fire" style?
If this had been the result of a barrel obstruction or excessive chamber pressure, the bolt would have been locked and it would have resulted in the barrel coming apart or the bolt lugs shearing
If this had been the result of a barrel obstruction or excessive chamber pressure, the bolt would have been locked and it would have resulted in the barrel coming apart or the bolt lugs shearing
Hmm I'm not sure about this, after watching the 2nd detonated M&P video above. In that case a squib blew the gun apart. In the aftermath the bolt had all its lugs and the barrel was intact.
themighty9mm
05-18-13, 01:02
I doubt it was an overcharged round cases fill almost to capacity on the 223 and unless it was pistol powder I dont see that happening.
The company I work for blew up a test gun using wc844 powder with a charge of a little over 27.5gr. Not sure the exact amount off the top of my head. The armorers estimated the pressure to be somewhere in the 80-100k psi range based off the damage. It was just an estimation, they could have been wrong. It was just based on what they had seen before. And unfortunately we were not doing pressure readings. It was just a unscientific function test. The damage was similar to what is shown in the pic, only the upper and lower receivers were just buldged and fractured, not shattered. The bolt carrier was split directly down the center to the key, the extractor was blown out but still pined in, and the rifle was locked up tight enough it took an armorer to get it open. I was the shooter, the rifle was a colt 6920. Only received a very minor burn to my wrist.
What I'm getting at is this sort of damage can certainly be done with a rifle powder. The fact the our test rifle did not shatter means little. The stress fractures were in very similar spots. It really only takes a few tenths of a grain to much powder. Especially when you are at the extreme upper limit.
Delayed ignition of the powder. Enough ignition of powder to push the bullet past the gas port allowing just enough pressure to unlock the bolt, then subsequent ignition of the remaining powder while bolt was unlocked and the round only partially in the chamber.
At least that was the "post mortem" on a very similar looking "kaboom" on an M16A1 on a range incident in the 80's at Camp Pendleton, CA.
Old ammo that has powder clumps, a very compressed powder charge (as happens with a completely filled case then the bullet is jammed in the neck) or it has also been proposed that in some cases a light powder charge with a weak primer ignition (but they have not been able to replicate it in labs) can all cause this type of event.
What could be happening to allow the bolt to unlock? I don't buy the delayed ignition of the powder thing because the peak pressure would occur long before the bullet reached the gas port.
I'm gonna think out loud for a moment to try to figure this out. Bolt is locked into the lugs of the barrel extension, so what's unlocking it if the catastrophic event is occurring before the gases reach the gas port? The energy has to be transferred somehow to cause the bolt to rotate and unlock.
What is actually breaking the upper? Is it high pressure gases being released unchecked into the upper, or is it the energy of the the shock wave being violently transferred from the barrel to the upper?
It was with these questions in mind that I removed an upper from a carbine to examine how the parts fit together and try to figure out what path the gases and/or stresses from the shock wave might take.
It turns out the front of the carrier is making contact with the rear of the barrel extension. This is why carrier bounce occurs when the carrier closes at too much speed. This contact would allow the transfer of the shock wave of the pressure peak to the carrier to bounce it back and open the bolt. It would be like hitting the front of the carrier with a hammer.
It's also likely it's this same shock wave that causes the upper receiver to split. The barrel extension is likely to be flexing and/or bulging at this point. This would most certainly cause the upper to fail.
The next question is, how is the bottom of the mag being blown out? My guess it's the high pressure gas being released into the action. As the gas simply blows the bottom out of the mag and rarely damages the lower, this leads me to believe the upper isn't being destroyed by the pressure of gases being released into the action.
This is just me thinking out loud, but it makes sense and would explain why the barrel & barrel extension are not damaged and why the bolt lugs are not sheared. Of course, this also assumes the barrel extension lugs remain intact
Looking at all that has to go right with the gun, it is amazing they work as reliably as they do. It seems just a small fraction of anything being out of alignment and the works get gummed up.
The pictures are worth a thousand words. Look at the ones we are all talking about. Looking at the unaffected parts, that gun looks very well used. In my mind, it is a questions of, how often did they maintain the rifle, or how often did they do a full strip down and clean of the rifle? Sure is says Military Police...still.
Hope the MP is ok.
Army Chief
05-18-13, 11:37
The comments section at the bottom of the page is worth a read, as a former Diemaco employee has provided some pretty respectable insights on the situation.
AC
Just did some pruning.
Anybody else who wants to try and introduce a roll-mark element to this....please don't. Even causal mention of that is like a Star of Bethlehem that'll draw idiots, instead of Magi.
Let the roll-mark derpers stay where they derp, so they can derp in tranquility, and may the light in their eyes continue to shine forth from the hole in the back of their heads.
Heavy Metal
05-18-13, 13:38
Who knows, maybe the front .50" of the firing pin was broken off and protruding, "slam-fire" style?
Never heard of a M-16 Firing Pin breaking like that.
Grand58742
05-18-13, 14:28
The lower, minus the bolt catch, looks surprisingly intact. I would have figured with that kind of catastrophic failure the mag well would have been visibly distorted at the least.
Case failure...
I'd be willing to bet good photos of the extractor and extractor groove in the bolt would show signs of high heat (burn marks). When the case fails, it can't obturate properly and the high pressure gas escapes through the extractor groove into the upper receiver and through the magazine with catastrophic effects.
Split66
That M&P15 was casue by a case seperation- slow it down and when he removed the casse prior to the Kaboom only part of the case comes out - next round stuffed into the chamber boom! :rolleyes:
DIRTMAN556
05-19-13, 01:42
I'll go with bore obstruction....
Reminds me of this vid of an M&P 15 Sport coming apart
http://www.youtube.com/watch?v=qoZnCxqa4QA
http://www.youtube.com/watch?v=HIuTVfl8G2U
Woah! Crazy!!
Split66
That M&P15 was casue by a case seperation- slow it down and when he removed the casse prior to the Kaboom only part of the case comes out - next round stuffed into the chamber boom! :rolleyes:
I slowed it down, looks like more than just the case head extracted. Also, how the heck could you get the rifle to go into battery with part of a 5.56 case in the chamber??
scary stuff... hope it doesnt happen to me. so a out of battery fire would be when the bullet is detonated when not locked and chambered in the barrel extension?
polymorpheous
05-19-13, 10:15
scary stuff... hope it doesnt happen to me. so a out of battery fire would be when the bullet is detonated when not locked and chambered in the barrel extension?
Which can not happen in an AR15.
I could not get a clear enough view of the case prior to the kaboom but it look like just the neck was missing ! If that was the case then I would say it would be possible to get a round to completely chamber an fire especially if they are shooting .223 in a 5.56 chamber!
I could not get a clear enough view of the case prior to the kaboom but it look like just the neck was missing ! If that was the case then I would say it would be possible to get a round to completely chamber an fire especially if they are shooting .223 in a 5.56 chamber!
223 in a 5.56 chamber is fine.
Which can not happen in an AR15.
So it's not possible with a high, soft primer?
polymorpheous
05-19-13, 14:35
So it's not possible with a high, soft primer?
Do military munitions generally use soft primers?
And the answer is no.
The firing pin will only protrude past the bolt face when the bolt is locked.
polymorpheous
05-19-13, 14:42
From the comment section from the OP:
That is very cool. I was involved in investigating the blowing up of some Canadian made guns during my time as an engineer at Diemaco (a couple were intentional!) and I can tell you you got a spectacular one there.
A couple of observations: without either monkeying with the system or doing something deliberate, it is VERY difficult to get an out of battery initiation in an M16 design due to the design of the cam pin track in the bolt/carrier requiring the bolt to be in battery and rotated fully before the carrier comes forward in a straight line on the last part of the counter recoil stroke. This last movement (about 0.060") is also designed to be the movement that allows the firing pin to come into contact with the primer on hammer fall. If the bolt isn't rotated by the cam pin the carrier movement forward stops and the firing pin can not reach the primer. Firing out of battery is probably less likely than an in battery discharge with a very significant bore obstruction not too far down the barrel OR you had a super hot load, probably hotter than you could do with a case full of Bullseye though I can't say as I've never been allowed to try that. (I'd like to!) You are likely in the 100,000 psi plus range to get this kind of damage and likely over 125,000 -> 150,000. We fired proof rounds that regularly got to 90,000+ in the chamber (we measured them) and our C7s would eat those up all day and function fine so this was a spectacularly high pressure event to split things like that.
(As an aside on in vs out of battery, if you recall the carrier bounce issues of the M16 on auto in the 60s, these failures to fire were caused by that last 0.060" bounce back happening as the auto sear released the hammer but before the hammer could fall the carrier literally bounced back off the barrel extension coming straight back and when the hammer hit the firing pin it was prevented from protruding out the bolt and contacting the primer. This led to huge experiments with floating buffer weights to reliably solve.)
The removal of the extractor at high speed is typically expected as is the blow out of the magazine. Also the splitting of the upper is common in such events (though this one is on the spectacular end of the spectrum for certain). Splitting the carrier body is also indicative of a superb event, I've split them but not to the extent of fracturing off large chunks on the sides like this event. The bottom of the carrier between the deeper cuts for the magazine lip clearance usually is the path of the split there, but this one did that and blew out the right side. Nice. The key being intact says not likely did much gas blow through the gas tube.
Its interesting that the bolt actually was driven rearward and rotated clockwise rather than counterclockwise as it normally would. If the obstruction was far enough to allow the gas tube to fill and/or it was SO violent that even though the obstruction was likely blown out, it seems it was already past the time that the action had started to loose integrity. The other culprit might be someone playing with the bits and moving them after the fact as it should have been in lock on the left side.
Epically cool series of pictures. Do you have anything looking down the bore or showing if there is anything left of the cartridge case in the chamber or welded to the bolt face? Also interesting it is an A2 Commando and it doesn't look to have US Govt markings (if so it wasn't sold FMS...) Too bad they really did a job on the serial number!
Phil
texasgunhand
05-19-13, 23:11
Good reason to wear gloves....That one was really bad...
Do military munitions generally use soft primers?
And the answer is no.
The firing pin will only protrude past the bolt face when the bolt is locked.
Yeah, no third world country would ever use shit ammo.
polymorpheous
05-20-13, 00:13
Yeah, no third world country would ever use shit ammo.
I'm sure their ammo is no worse than some of the imported stuff we get.
All that aside...
The fact remains, you can not fire the AR platform out of battery.
Well you might be interested to know that Magtech ammo is made in Brazil and it is good ammo. What do you think the odds are that they probably use it?
Yeah, no third world country would ever use shit ammo.
The damage to that A2 upper is nothing short of incredible. I mean... that's a ****in STRONG part and it is bent like a noodle. :eek:
Well you might be interested to know that Magtech ammo is made in Brazil and it is good ammo. What do you think the odds are that they probably use it?
^^^THIS^^^ Thoughts on how good or not good the Brazilian army happens to be, the fact is that a ton of good ammo is made right in Brazil.
Just had a thousand rounds show up from Grant. I can tell you that even the glue they use on the cases is top notch.
That upper has got to be one of the worst failures that I have ever seen.
1_click_off
05-20-13, 22:02
I took my friend out shooting for the first time, he was very worried about just releasing the charge handle and letting the bolt fly home. He had the gun pointed down and slowly released the charge handle. It did not go to battery. He then pulled it back again. Only issue now is the first round had just enough force put on it the feed lips did not hold it and it came out of the mag and chambered. He then let the charge handle go and ripped the next round right into the chambered round. It hit with enough force to push the lead into the case, but not enough to do more than dent the primer.
If it had hit the primer with more force, I could see the chambered round going off, the gases from the gas tube returning to the chamber and finding the fresh case with the projectile now shoved in it and igniting the powder in it.
Just a thought.....
Edit: we were shooting SP ammo, FMJ might have set it off.
I've set up dozens of training related failures to extract clearance drills in carbine classes by dropping a round into the chamber and then releasing the charging handle to load another round behind it. It's never been an issue. Even if one went kaboom, I doubt with having the base exposed it would generate enough force to do what is pictured in the OP. Also, there really would be no way to ignite the powder in that second round just because the one in front of it went off, hot gasses from the first round would not be enough.
1_click_off
05-21-13, 06:37
I've set up dozens of training related failures to extract clearance drills in carbine classes by dropping a round into the chamber and then releasing the charging handle to load another round behind it. It's never been an issue. Even if one went kaboom, I doubt with having the base exposed it would generate enough force to do what is pictured in the OP. Also, there really would be no way to ignite the powder in that second round just because the one in front of it went off, hot gasses from the first round would not be enough.
You are most likely correct. The bullet being knocked into the case now offers no contained power and should simply just burn off(if ignited).
The damage to that A2 upper is nothing short of incredible. I mean... that's a ****in STRONG part and it is bent like a noodle. :eek:S@W is not a high quality AR type.
S@W is not a high quality AR type.
Can you say without a doubt that a Noveske would not have been damaged the same in such an incident?
Mark's comment was towards the OP's picture which showed a COLT A2 upper destroyed.
As an aside, M&P 15's, even Sports, use 7075T6 forgings from the same places everyone else does.
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