Out of battery question w/pictures
- Thread starter Jon.
- Start date
Did you pick up the fired brass?
If the round before this one had case separation leaving the forward half stuck in the chamber, the following round could jam into it about the way that looks there. Bolt could still close with that sloppy/huge cam pin cut out in the upper so the firing pin could hit the primer, but it would be outside against the extension instead of in it. OEM cam pin at the time, or something else?
Now the hammer shouldn't be able to hit the firing pin in that situation, the cam pin would bind up unless in the cut out, but we are talking about BCL here, not exactly the brightest bunch in regards to tolerances.
Get the case out and see what that looks like.
If the round before this one had case separation leaving the forward half stuck in the chamber, the following round could jam into it about the way that looks there. Bolt could still close with that sloppy/huge cam pin cut out in the upper so the firing pin could hit the primer, but it would be outside against the extension instead of in it. OEM cam pin at the time, or something else?
Now the hammer shouldn't be able to hit the firing pin in that situation, the cam pin would bind up unless in the cut out, but we are talking about BCL here, not exactly the brightest bunch in regards to tolerances.
Get the case out and see what that looks like.
Cameron SS
CGN Ultra frequent flyer
- Location
- Ground Zero
Ive read so many threads and stories about AR Out of Battery detonation.
100% of every AR15 OoB Ive ever heard of all have two things in common.
1. Firer insists reloads are known to be good and are not an issue.
2. OoB detonation involved reloads.
Imgur wont let me view the photos for some reason.
I suspect the hammer was intact prior to the detonation, and the broken hammer is a caused by, and not the cause of the issue.
Double charge and high priner are always the two most likely culprits. Unfortunately neither condition is directly observable after the facts.
Did the person squeeze the trigger while the bolt was moving, or did the bolt come to rest out of battery and then the firer pulled the trigger and the hammer dropped?
Or did round fire during cycling of the gun without activation of the trigger.
Agree with the other guy that a look at the last few fired cases would be nice. Also if the round from the OoB hit paper, where? Chronograph?
Did the detonation look like this? https://youtu.be/xhgyJMhQFbA
That video is from attempting to fire a handload through an obstructed barrel/chamber. If the explosion you saw was much more violent then double charge seems more likely.
100% of every AR15 OoB Ive ever heard of all have two things in common.
1. Firer insists reloads are known to be good and are not an issue.
2. OoB detonation involved reloads.
Imgur wont let me view the photos for some reason.
I suspect the hammer was intact prior to the detonation, and the broken hammer is a caused by, and not the cause of the issue.
Double charge and high priner are always the two most likely culprits. Unfortunately neither condition is directly observable after the facts.
Did the person squeeze the trigger while the bolt was moving, or did the bolt come to rest out of battery and then the firer pulled the trigger and the hammer dropped?
Or did round fire during cycling of the gun without activation of the trigger.
Agree with the other guy that a look at the last few fired cases would be nice. Also if the round from the OoB hit paper, where? Chronograph?
Did the detonation look like this? https://youtu.be/xhgyJMhQFbA
That video is from attempting to fire a handload through an obstructed barrel/chamber. If the explosion you saw was much more violent then double charge seems more likely.
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Triggertech
I'm presuming the reloads were good as it's the first time I've ever had an issue in over 10 years, and hundreds from the same batch were shot out of that or a rem700 that day. I'm not above having it a reloading issue. Would the rifle have enough recoil and movement to cause a primer to slip out backwards a bit?.
No double charges. It's varget. I'd need a hydraulic press to somehow fit in a double charge. Even a compressed load shouldn't have done that. But seeing as it never made it into the chamber it doesn't really matter what was in the case, it was set off prematurely somehow.
I do enjoy the discussion and theories, that's 90% of the reason I posted up here. Thanks.
I took a second look at your photos, and the second photo you posted - of the brass still in the chamber, shows that the barrel extension is not indexed properly. If I recall right, BCL (not known for their great QA/quality) had a recall/notice out about some of their barrels/barrel extensions not being indexed properly.
It looks like your bolt functioned properly, it stripped, fed, chambered and locked... however with the barrel extension slightly out of index, it looks like when the firing pin struck the primer, the lugs on the bolt were not fully supported which allowed the bolt and carrier assembly to travel rearward, which is why you didn't experience an OOB in technical sense.
It might also explain why you saw the gouge in the upper receiver in the cam pin pocket, where it transitions to the slot for the charging handle/cam pin to ride in when the bolt is unlocked. That gouge seems to indicate the cam pin slammed into the transition point.
Thankfully no one was injured... but BCL absolutely produced a hunk of junk in letting that rifle out.
EDIT: Here's the link to the BCL recall. ht tps://blackcreeklabs.com/wp-content/uploads/2019/07/Barrel-Alignment-Inspection.pdf
I can't overstate how crappy their products must be for letting guns out that produce these kinds of malfunctions.
It looks like your bolt functioned properly, it stripped, fed, chambered and locked... however with the barrel extension slightly out of index, it looks like when the firing pin struck the primer, the lugs on the bolt were not fully supported which allowed the bolt and carrier assembly to travel rearward, which is why you didn't experience an OOB in technical sense.
It might also explain why you saw the gouge in the upper receiver in the cam pin pocket, where it transitions to the slot for the charging handle/cam pin to ride in when the bolt is unlocked. That gouge seems to indicate the cam pin slammed into the transition point.
Thankfully no one was injured... but BCL absolutely produced a hunk of junk in letting that rifle out.
EDIT: Here's the link to the BCL recall. ht tps://blackcreeklabs.com/wp-content/uploads/2019/07/Barrel-Alignment-Inspection.pdf
I can't overstate how crappy their products must be for letting guns out that produce these kinds of malfunctions.
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Well let me destroy that internet wisdom... I blew up a factory built Colt A2 Sporter with factory Federal ammo, broken firing pin lodged in the bolt face was the best that could be concluded from the autopsy. wasn’t even a high round count gun, maybe 5000rnds... it does happen, just not often. BCL’s shockingly bad quality leaves no options off the table, loose barrel extensions are their trademark.
Runningfool
CGN Ultra frequent flyer
- Location
- SW Ontario
The best that could be concluded? Wouldn’t a broken firing pin lodged in the bolt face be pretty evident? You have any pics?
redshooter
CGN Ultra frequent flyer
- Location
- Central Ontario
Well since it's pretty much one of three things it's a pretty fair statement, the only other is wrong powder, and I'd assign that only if it was the first shot out of a batch of reloads.
I'd trust his judgment in this case, and shoot his reloads for that matter, in fact I did yesterday, and it made me sad, his recipe is better than mine, almost 2" less drop at 300m.
Never found the whole primer, just the anvil.
Just to throw another twist in, I managed to get it apart today. Barrel extension pin seems to be sheared off clean. I don't know if that was factory as I've never taken the barrel off, but I also couldn't find the rest of the pin, and it's a pretty self contained unit. So that explains why in the photo the alignment was off.
Case is in pieces but looks to have separated below the shoulder.
So question, could the lack of barrel extension pin throw off the alignment, and that cause the bolt to be almost but not quite engaged? Not enough of a lockup time to let the pressure out? Blowing the bcg backwards causing the rest of the damage? Something like that?
Long before the common use of cell cameras or digital cameras at all really. How does one ever know absolute sure what happened with a blown up rifle, we can make educated guess and theories, but knowing for absolute sure is impossible. The firing pin was lodged firmly in the bolt face with enough protrusion to have been the problem, but maybe it was a result and not the cause.
Seems like the barrel extension was far enough out of alignment, your bolt should have locked, when it fact it did not, creating a blowback 308.. and well that obviously didn’t go well.
Yeah, after a better look, appears to be the index pin has turned under the ####ty BCL barrel nut, allowing this to happen. Check the top of the barrel extension, the pin is probably rotated under the barrel nut "holes" that should not be in any barrel nut, BCL invention there. The upper threads where the pin is supposed to be captive is probably crushed over a bit, soft crappy aluminum they use.
Nothing you did, this happened when it was made. Just took some time of partial lock up to fail.
Nothing you did, this happened when it was made. Just took some time of partial lock up to fail.
I think Hitzy is right on, not your fault, it’s just a POS assembled by a full blown monkey. Happy no one got injured by this embarrassment to canadian manufacturing. BCL ####ed a lot of people over with their piss poor engineering and materials.
100% the lack of or broken index pin could cause the barrel extension to be slightly mis-aligned. From a purely technical standpoint, the gas tube should eliminate some of the rotation and keep the barrel fairly aligned.. but I have no idea what BCL holds their location/tolerances to on the gas tube hole and diameter. I'm not implying that the gas tube is used as such.. but generally speaking it should not allow the barrel with the barrel extension assembled properly to rotate so far out of alignment that the bolt has nothing to lock against.
With the barrel extension sitting where it is in your photos, it's definitely misaligned by almost a full lug width.. which is enough to have allowed the bolt to close, but not actually lock against the mating surfaces, or only such a small amount that the bolt was barely held in the locked position.
As one of the above comments mentioned, your gun basically thought it was locked, but operated like a blowback firearm. Do you have photos of the separated brass? The pressure curve would have still be very high when the bolt started to travel rearward, so it seems to make sense that the case failed forward of the base, likely closer to the shoulder.
The BCG blowing back likely also caused the damage I mentioned previously where the cam pin slammed into the transition point between the cam pin pocket, and the track/raceway (same track the charging handle rides in)
Whatever was left of the index pin was either ground down or never there to begin with. It was almost clean sheared off with the barrel height.
The irony is aside from my own mishaps of trying to shoot old reloads that weren't full length resized, the gun had never given me any problems. And it's from the very first batch made.
The barrel nut has grooves in it for the gas tube to lay in. There's no way it could move more than a few mm without breaking or severely bending the gas tube.
You are correct, the brass separated just below the shoulder. I have some photos somewhere now, but it was a ##### to get out as it opened like a flower petal into the breech area. The damage from the cam pin actually kept me from being able to put the bcg back in to reassemble it. I had to take some small files and eventually a dremel to smooth it down.
I had to drill out the old index pin, installed a new one, put a basic trigger into it, and she seems functional now. Too bad we will never know.
Also big shout out to Triggertech. They're replacing this trigger pack for me, crazy good customer service, I just wanted to get it repaired. I wish I had more rifles to put trigger tech stuff in!
