BCL 102 catastrophic failure

[Suther]

If there was an out of battery discharge...

Can you conceive an alternative considering the condition of the case and the fact the bolt is stuck in the buffer tube? Clearly the bolt received far more force or energy then designed (which wasn't absorbed by the lugs like you'd expect from an over pressure round that was in battery), and judging by how the case is blown out (particularly in the neck area) I can't imagine that round was in battery all the way...

 

[slash547]

Managed to get the upper and lower apart and get the BCG out. Final pics below before I sent back to BCL. The bolt pin is bent and very difficult to move it to rotate the bolt. These pics should answer some of the recent questions/theories.

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[slash547]

OP - Please tell us you're not going to continue reloading commercial brass 5 times without trimming... Also, do you ever inspect your brass for incipient separation?

I will check every case now rather then 1 in 5. I am fully setup to trim so no problem there. What a safe number of reloades a 308 or any case can be used for-thoughts?

I shoot these same reloads in my BAR III and M1A1, hate to damage them

 

[slash547]

I suspect a broken firing pin. Years ago, I had a SPECTRE 9mm semi-auto go full-auto on me at the gun club for precisely that reason; the firing pin had broken and was jammed in the bolt sticking out just enough to set off the cartridges as they were being chambered. I remember loading the magazine into the gun, pulling back the bolt, releasing it and then BRAAAP! Finger was nowhere near the trigger, and fortunately the gun was pointed in a safe direction - two rounds through the bench, and three more rounds in the floor downrange before it jammed (it was a 30 round magazine.) The next day I brought the gun back and traded it in for a nice safe revolver lol.

The firing pin looked intact, it was very difficult however to push in and did not want to return. Could have been that way to start or damage from the KB

 

[SudburyShooter]

This happened to my brothers bcl aswell. Same kind of failure. Almost like the round went off out of battery.
Blew the magazine out of the gun, and baseplate off of the magazine. Quite the concussion.
I don’t know how they manage to repeat the quality. That’s the real amazing part.

 

[*MALICE*]

Barrel extension is not indexed properly in the receiver.......

If the lugs couldn't enter the extension, and the bolt 'telescoped' into the carrier outside of the extension..........

 

[Brian46]

If there was an out of battery discharge...

What other explanation is there if the BCG has all the lugs as the op has stated?

 

[SudburyShooter]

 

[slash547]

What other explanation is there if the BCG has all the lugs as the op has stated?

Lugs look fine. See my pictures a couple post before this

 

[slash547]

What are you showing us with this pic?

 

[Xterra282]

one of the doctors I work with just picked one of these not too long ago. I will definitely let him know to keep an eye on his reloads ( if he does reload I am note sure)

 

[SudburyShooter]

What are you showing us with this pic?

The index pin..

 

[Brian46]

Lugs look fine. See my pictures a couple post before this

That is my point, clearly it is an out of battery discharge. Pulling the trigger should not have dropped the firing pin on the round.

 

[Brian46]

one of the doctors I work with just picked one of these not too long ago. I will definitely let him know to keep an eye on his reloads ( if he does reload I am note sure)

The evidence points to an out of battery discharge, bolt lugs appear undamaged and round went off when trigger was pulled.

 

[Xterra282]

I will most likely send him over this way to have a 24+ page read about this potential re-occurring issue.

 

[Bonjour43ma]

Oh wow the barrel extension index pin went UNDER the upper receiver barrel threads! Seems like the force of the bolt lugs rotating on the extension was so much that the index pin gouged into the threads. Insane. That's the soft 6061/whatever aluminum BCL uses for their receivers...

 

[SudburyShooter]

Apparently the melt down pop can tabs, or the beer can tabs from the QC dept.

 

[Gas Can]

So if the barrel/barrel extension isnt indexed properly(out a couple degrees counter clockwise), then the bolt lugs will not completely engage when rotating counter clockwise going into battery?

Are the corners of the bolt lugs chipped off?

Looks like there is only 50% engagement and over time the corners on the bolt lugs failed until the final failure.

Also, with the bolt unlocking prematurely, the top of the cam pin dosnt fully retract from the bolt cam pin recess, dragging on the side of the upper receiver keyway, bending/gouging it over time.

Could the stove pipes be a sign of a gas leak from the key and tube being maligned?

GC

 

[Gas Can]

DTap

 

[tiriaq]

Managed to get the upper and lower apart and get the BCG out. Final pics below before I sent back to BCL. The bolt pin is bent and very difficult to move it to rotate the bolt. These pics should answer some of the recent questions/theories.

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Looking at these photos:
-the barrel is rotated slightly.
-the cam pin is bent. You report that the bolt is stiff in the carrier.

OK, the carrier assembly runs forward. Because the barrel is slightly rotated, the bolthead does not enter the barrel extension, and stops. The carrier's momentum forces the bolt to rotate as the carrier continues forward. This allows the hammer to make contact with the firing pin. Boom.
The stoppages prior to the failure suggest that the rifle wasn't functioning properly; maybe the situation was developing.

SudburyShooter posted photos of a barrel breech rotated in the receiver, with the indexing pin being forced into the receiver. I wonder if yours is like this?
Wonder if this was done on initial assembly?