need advice - AR15 Kaboom

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tangolima

New member
The bolt is still locked, at least partially, so it could not have been an out-of-battery ignition. The casing is still in the chamber. Getting it out will tell most, if not all, of the story. A blown casing / primer seems likely. After the shot, and the blown away parts, the gas system still tried to open the bolt, but couldn't completely, and hence the partially locked bolt head.

The partially disengaged lugs show brass color, do they not? Or it is the photo doing tricks on my old eyes. Coating of brass on steel that shouldn't have had contact with brass is an indication of hot gas with molten brass. If there is such sign on the blown parts, a blown casing would be most certain.

-TL
 
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Tidewater_Kid

New member
Maybe it's just me eyes, but I see something that looks like debris on the right corner.

attachment.php


Lighten the image some.
 

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rickyrick

New member
Took a second look on a big screen:

The other visible bolt lugs are at least partially engaged with the barrel extension.

The object in question is in its channel, and possibly protruding out from the extension.

I did have an ejector roll-pin walk out of a bolt and it had bent over.

I can't honestly say for sure, but it sorta looks like the tip of a roll pin, but not saying that's what it is.
 
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stagpanther

New member
My wild guesses: vaporized brass deposits accounts for the color and the vertical striations damage from the lugs forcibly "pulsing" against the extension on detonation.
 
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HiBC

New member
Really? The skinny line?

I'm accustomed to Varget,RE-15.etc,and 69 gr + bullets.

I typically get powder fill approx. to the neck,and most loads are near 100% to lightly compressed.

With those combinations,significant bullet setback requires compressing powder.

With what your line shows,there is plenty of space for a bullet to setback.

That does make the setback theory more believable,for myself.
And,It gives me more cause to like the powders/bullets I use.

RE15 is my go-to with the 75-77 gr bullets.( I use 24.3 gr with the 75 gr Horn) I had excellent resuts with Varget shooting 69 gr Sierras.(I used 25 gr Varget)

That 69 gr load gave me 2780 out of a 16 in H-bar 1 in 9.Excellent accuracy And my BCG stayed pretty clean.
 
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DMK

New member
I'm confused here. If the bolt and carrier are still locked in place, how did the pressure get by the bolt to blow the magazine out?
 
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IMtheNRA

New member
A question for the OP: did this round leave a hole in the target and if so, does the hole appear normal or was it made by a damaged or partial bullet?
 
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darkgael

New member
Targets

As far as I could tell, the bullet did not make it to the target. There were three holes from the first three shots. No fourth hole that I could see.
 
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IMtheNRA

New member
It would be useful to see the inside of that chamber and bore. Have you removed the bolt yet? Is the bullet smeared all over that chamber?
 
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stagpanther

New member
That's a real stumper and honestly have no informed idea-- cause it looks like everything is locked together as a result of the detonation. I was hoping an AR expert smith with experience with this would post something.

Looking at it from strictly the "least invasive" point of view--meaning not cutting or drilling anything out, I don't know how you would get the bolt unlocked from the carrier. My initial (inexperienced) approach would be to somehow get the bolt unlocked from the extension, so I would explore removing the barrel nut and seeing if creating some play between the extension and the bolt lugs might be a path (possibly driving the extension gas port key pin out?) I thought about trying to remove the extension from the barrel but that requires a heck of a lot of torque.

In other words, haven't a clue. : )
 
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HiBC

New member
Have you tried the inertia techniques?
There is some weight in the bolt carrier.The cam translates linear force to rotational force.
The assembly can work like an impact wrench.

Is that upper useable? If not,what have you got to lose?

A few vigorous vertical slams,muzzle up,rear of the receiver coming to an abrupt stop,might get it done. Maybe
 
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