Carbon 15 Rifles, Rife Detonations, and YOU PICS AHOY!

[ARCHIVED THREAD] - Carbon 15 Rifles, Rife Detonations, and YOU PICS AHOY! (Page 1 of 2)

Posted: 4/28/2012 11:06:48 PM EDT

A customer of mine brought his formerly new Bushmaster Carbon 15 into the shop this afternoon. As best as I can tell, he had an OOB case separation while running Hornady 75gr Superperformance loads. Buffer tube, stock, most of the upper receiver, and assorted parts were not easily found at the scene (according to the fellow)

No Barrel obstruction was noted when I was handling the severed barrel.

No injuries to the owner, but catastrophic damage to the rifle. EDIT: I forgot that the TRUGLO red dot hit him in the face and destroyed his issued eyepro. THIS is why its important to wear eyes and ears kids! Advised him to call Bushmaster for a RMA and Magpul about the PMAG. Apparently the PMAG survived an IED in AFG and is still combat functional after this detonation. Color me impressed.

The funny thing is, inside the lugs on the barrel and forward, plus the bolt and carrier, look functional still. Granted, I wouldn't advise it, but I thought that was interesting.

TOP PHOTO: That strap between the carrier and buffer is the largest part of the upper he found. Its pretty much the rail from the top all screwed up.

Posted: 4/28/2012 11:11:55 PM EDT

[#1]

DEEEEEEE-AAAAMMMMMNNNNNNN!!!!

Glad he's OK. I'd be contacting Hornady, too.

Wow. Just... wow.

Posted: 4/28/2012 11:12:53 PM EDT

[#2]

Pmag ftw!

Posted: 4/28/2012 11:14:07 PM EDT

[#3]

Quoted:
DEEEEEEE-AAAAMMMMMNNNNNNN!!!!

Glad he's OK. I'd be contacting Hornady, too.

Wow. Just... wow.

Honestly, I didn't even think of telling him to contact them. Bushmaster probably will tell him to though.

As best as I could tell it was not an overcharge, but it could have been a misformed case (impossible to tell at this point) preventing it from fully chambering the round. As the case was still stuck in the chamber, who knows at this point.

I took photos and did NOT poke around to keep from damaging/tainting the parts for manufacturer inspection.

Posted: 4/28/2012 11:18:23 PM EDT

[#4]

Quoted:
Pmag ftw!

Lol I know right. I never figured one would survive a DIRECT (according to the story LT pushed a guy who was hitting a trip wire out of the way) hit from an IED and then still be functional after getting blasted out of a rifle.

Damn good stuff

Posted: 4/28/2012 11:28:07 PM EDT

[#5]

Quoted:

Quoted:
DEEEEEEE-AAAAMMMMMNNNNNNN!!!!

Glad he's OK. I'd be contacting Hornady, too.

Wow. Just... wow.

Honestly, I didn't even think of telling him to contact them. Bushmaster probably will tell him to though.

As best as I could tell it was not an overcharge, but it could have been a misformed case (impossible to tell at this point) preventing it from fully chambering the round. As the case was still stuck in the chamber, who knows at this point.

I took photos and did NOT poke around to keep from damaging/tainting the parts for manufacturer inspection.

On a properly functioning AR without parts missing or massive cam surface wear:

If a round will not properly chamber, the bolt will not lock.

If the bolt is not locked, the firing pin cannot contact the primer.

No primer contact = No OOB ignition.

This is 100% on AR15 design. That's how the gun works. Period. End. Fucking dot.

Inspect for a cam pin... Inspect wear on said pin. Inspect the caming surface in the bolt carrier for insane wear.

Cam pin there? No insane wear? Then the bolt must have been locked for the firing pin to contact primer.

Either something was totally FUBARed epically on the gun, or the gun was in battery when the KaBoom started. Or a cosmic ray ignited the primer while the round chambered.

Posted: 4/28/2012 11:31:13 PM EDT

[#6]

Quoted:

Quoted:
DEEEEEEE-AAAAMMMMMNNNNNNN!!!!

Glad he's OK. I'd be contacting Hornady, too.

Wow. Just... wow.

Honestly, I didn't even think of telling him to contact them. Bushmaster probably will tell him to though.

As best as I could tell it was not an overcharge, but it could have been a misformed case (impossible to tell at this point) preventing it from fully chambering the round. As the case was still stuck in the chamber, who knows at this point.

I took photos and did NOT poke around to keep from damaging/tainting the parts for manufacturer inspection.

On a properly functioning AR without parts missing or massive cam surface wear:

If a round will not properly chamber, the bolt will not lock.

If the bolt will not lock, the firing pin cannot contact the primer.

No primer contact = No OOB ignition.

This is 100% on AR15 design. That's how the gun works. Period. End. Fucking dot.

Inspect for a cam pin... Inspect wear on said pin. Inspect the caming surface in the upper for insane wear.

Cam pin there? No insane wear? Then the bolt must have been locked for the firing pin to contact primer.

Hmmm... Color me confused then. The section I am holding of the case head in the photo was sheared/blew off in the locking lug section of the bolt/barrel extension area. The primer has been fired.

Wonder what could have caused it then. This was just a cursory 5 minute thing mind you.

No cam pin wear was noted.

I'll correct the OP and remove that hypothesis. Excessive headspace would probably not be it unless runout on the machines was insane the day it was made. (purchased yesterday) So could be an overcharge, but cannot confirm/deny.

Posted: 4/28/2012 11:36:14 PM EDT

[#7]

Quoted:

Quoted:
DEEEEEEE-AAAAMMMMMNNNNNNN!!!!

Glad he's OK. I'd be contacting Hornady, too.

Wow. Just... wow.

Honestly, I didn't even think of telling him to contact them. Bushmaster probably will tell him to though.

As best as I could tell it was not an overcharge, but it could have been a misformed case (impossible to tell at this point) preventing it from fully chambering the round. As the case was still stuck in the chamber, who knows at this point.

I took photos and did NOT poke around to keep from damaging/tainting the parts for manufacturer inspection.

On a properly functioning AR without parts missing or massive cam surface wear:

If a round will not properly chamber, the bolt will not lock.

If the bolt will not lock, the firing pin cannot contact the primer.

No primer contact = No OOB ignition.

This is 100% on AR15 design. That's how the gun works. Period. End. Fucking dot.

Inspect for a cam pin... Inspect wear on said pin. Inspect the caming surface in the upper for insane wear.

Cam pin there? No insane wear? Then the bolt must have been locked for the firing pin to contact primer.

Hmmm... Color me confused then. The section I am holding of the case head in the photo was sheared/blew off in the locking lug section of the bolt/barrel extension area. The primer has been fired.

Wonder what could have caused it then. This was just a cursory 5 minute thing mind you.

No cam pin wear was noted.

Take an assembled AR-15/M16/M4 bolt carrier group.

Push the bolt into the locked position.

Press forward on firing pin.

See it protrude?

Now pull the bolt out just a bit... Try the firing pin... You'll notice it ceases protruding before the lugs begin to rotate.

Unlocked bolt = Firing pin no smash primer.

Posted: 4/28/2012 11:38:07 PM EDT

[#8]

Quoted:

Quoted:
DEEEEEEE-AAAAMMMMMNNNNNNN!!!!

Glad he's OK. I'd be contacting Hornady, too.

Wow. Just... wow.

Honestly, I didn't even think of telling him to contact them. Bushmaster probably will tell him to though.

As best as I could tell it was not an overcharge, but it could have been a misformed case (impossible to tell at this point) preventing it from fully chambering the round. As the case was still stuck in the chamber, who knows at this point.

I took photos and did NOT poke around to keep from damaging/tainting the parts for manufacturer inspection.

On a properly functioning AR without parts missing or massive cam surface wear:

If a round will not properly chamber, the bolt will not lock.

If the bolt will not lock, the firing pin cannot contact the primer.

No primer contact = No OOB ignition.

This is 100% on AR15 design. That's how the gun works. Period. End. Fucking dot.

Inspect for a cam pin... Inspect wear on said pin. Inspect the caming surface in the upper for insane wear.

Cam pin there? No insane wear? Then the bolt must have been locked for the firing pin to contact primer.

Hmmm... Color me confused then. The section I am holding of the case head in the photo was sheared/blew off in the locking lug section of the bolt/barrel extension area. The primer has been fired.

Wonder what could have caused it then. This was just a cursory 5 minute thing mind you.

No cam pin wear was noted.

Take an assembled AR-15/M16/M4 bolt carrier group.

Push the bolt into the locked position.

Press forward on firing pin.

See it protrude?

Not pull the bolt out just a bit... Try the firing pin... You'll notice it ceases protruding before the lugs begin to rotate.

Unlocked bolt = Firing pin no smash primer.

Thats what I thought, but its been 2 years since I've properly owned an AR15. Had to hock it to help pay for cancer treatments, but thats another story.

Thanks for confirming my thoughts though. I'm hoping guy will come back in once he hears back from whatever manufacturer gets it and lets me know what it was.

Posted: 4/28/2012 11:39:23 PM EDT

[#9]

the greatest part about this is the atacs hydroprinting

i would be fucking livid

Posted: 4/28/2012 11:42:09 PM EDT

[#10]

A fully plastic rifle exploded. Color me shocked.

Posted: 4/28/2012 11:44:53 PM EDT

[#11]

Quoted:
A fully plastic rifle exploded. Color me shocked.

Lol a fully carbon fiber rifle fully exploded... Fully

Posted: 4/28/2012 11:49:20 PM EDT

[#12]

Wasn't there issues a little while back with certain batches of Superperformance?

Posted: 4/28/2012 11:50:27 PM EDT

[#13]

Bore obstruction? Simplest possible cause.

Beyond that, I got nothing. Barrel extension is at least vaguely in proper timing with the upper, which blows a theory I had out of the water.

Magnum pistol powder in a factory load?

Aliens?

Posted: 4/28/2012 11:55:34 PM EDT

[#14]

Quoted:
Bore obstruction? Simplest possible cause.

Beyond that, I got nothing. Barrel extension is at least vaguely in proper timing with the upper, which blows a theory I had out of the water.

Magnum pistol powder in a factory load?

Aliens?

Unless the guy had the presence of mind to knock a squib out after detonation, I have no ideas. Barrel looked good from the outside. *shrug*

Posted: 4/28/2012 11:55:38 PM EDT

[#15]

Shouldn't have been shooting superformance in the first place.

Posted: 4/28/2012 11:57:17 PM EDT

[#16]

Quoted:
Shouldn't have been shooter superformance in the first place.

Why not? The barrel was spec'd for it. Granted its not the most accurate stuff out of AR rifles, but I don't know of any reason not to.

Posted: 4/28/2012 11:59:29 PM EDT

[#17]

Quoted:

Quoted:
Shouldn't have been shooter superformance in the first place.

Why not? The barrel was spec'd for it. Granted its not the most accurate stuff out of AR rifles, but I don't know of any reason not to.

Well, I'd say you might have a pile of reasons not to pictured above.

(Disclaimer: We don't know it was the ammo).

I kinda amazed this guy didn't get some carbon fiber in his face... Rowdy looking kaboom. Glad he's okay.

He wasn't playing in water or anything, was he? Bore full of water can be bad.

Posted: 4/29/2012 12:01:28 AM EDT

[#18]

Due to the longer duration of peak pressure produced by Superformance™, the post peak/declining port pressure at common carbine and mid-length gas port locations is still higher than that produced by standard propellant. This has a tendency to flood the system with a larger volume of gas, at a higher velocity, that tries to open the bolt of the gun too fast. It’s a timing issue. The cartridge case is still swollen from the application of pressure during firing while the gun is simultaneously trying to extract the cartridge case before it has had an opportunity to settle back to its original size, or more simply: the gun is still in the process or firing while it’s trying to extract the cartridge case.

Not blaming the Kaboom on the fact of the ammo being superformance. But Superformance is not meant for carbine gas systems. Tons of people have reported popped primers. But if the guy would have looked this up, he would never have bought the bad ammo in the first place and his gun would still be in one piece

On another note, there was a guy in the ammo section within the last 2 weeks with .308 superformance ammo piercing primers.

Posted: 4/29/2012 12:03:24 AM EDT

[#19]

Quoted:

Quoted:
Shouldn't have been shooter superformance in the first place.

Why not? The barrel was spec'd for it. Granted its not the most accurate stuff out of AR rifles, but I don't know of any reason not to.

Well, I'd say you might have a pile of reasons not to pictured above.

(Disclaimer: We don't know it was the ammo).

Quoted:
http://www.hornady.com/assets/templates/site/images/superformance_pressurevsgas.JPG

Due to the longer duration of peak pressure produced by Superformance™, the post peak/declining port pressure at common carbine and mid-length gas port locations is still higher than that produced by standard propellant. This has a tendency to flood the system with a larger volume of gas, at a higher velocity, that tries to open the bolt of the gun too fast. It’s a timing issue. The cartridge case is still swollen from the application of pressure during firing while the gun is simultaneously trying to extract the cartridge case before it has had an opportunity to settle back to its original size, or more simply: the gun is still in the process or firing while it’s trying to extract the cartridge case.

Not blaming the Kaboom on the fact of the ammo being superformance. But Superformance is not meant for carbine gas systems. Tons of people have reported popped primers. But if the guy would have looked this up, he would never have bought the bad ammo in the first place and his gun would still be in one piece

On another note, there was a guy in the ammo section within the last 2 weeks with .308 superformance ammo piercing primers.

Huh...good to know

Posted: 4/29/2012 12:04:11 AM EDT

[#20]

Quoted:
http://www.hornady.com/assets/templates/site/images/superformance_pressurevsgas.JPG

Due to the longer duration of peak pressure produced by Superformance™, the post peak/declining port pressure at common carbine and mid-length gas port locations is still higher than that produced by standard propellant. This has a tendency to flood the system with a larger volume of gas, at a higher velocity, that tries to open the bolt of the gun too fast. It’s a timing issue. The cartridge case is still swollen from the application of pressure during firing while the gun is simultaneously trying to extract the cartridge case before it has had an opportunity to settle back to its original size, or more simply: the gun is still in the process or firing while it’s trying to extract the cartridge case.

Not blaming the Kaboom on the fact of the ammo being superformance. But Superformance is not meant for carbine gas systems. Tons of people have reported popped primers. But if the guy would have looked this up, he would never have bought the bad ammo in the first place and his gun would still be in one piece

On another note, there was a guy in the ammo section within the last 2 weeks with .308 superformance ammo piercing primers.

Carbine gas, long peak.

Sounds like weak case and high pressure still in bore.

Posted: 4/29/2012 12:04:42 AM EDT

[#21]

Here is what happens with superformance in a gun with a carbine gas system

Here is the guy with .308, he was using a midlength gas system...For non reloaders the brass shows excess pressure

Posted: 4/29/2012 12:05:25 AM EDT

[#22]

Quoted:
Wasn't there issues a little while back with certain batches of Superperformance?

yes

Posted: 4/29/2012 12:10:11 AM EDT

[#23]

Quoted:
Here is what happens with superformance in a gun with a carbine gas system

http://i31.photobucket.com/albums/c353/AJErvin/Guns/IMG00147-20110610-1537.jpg

Here is the guy with .308, he was using a midlength gas system...For non reloaders the brass shows excess pressure

http://i426.photobucket.com/albums/pp343/Scottyman_01/Primer.jpg

Oh damn... good to know though.

Posted: 4/29/2012 2:31:15 AM EDT

[#24]

Bump for morning guys

Posted: 4/29/2012 2:42:54 AM EDT

[#25]

Quoted:

Quoted:
Here is what happens with superformance in a gun with a carbine gas system

http://i31.photobucket.com/albums/c353/AJErvin/Guns/IMG00147-20110610-1537.jpg

Here is the guy with .308, he was using a midlength gas system...For non reloaders the brass shows excess pressure

http://i426.photobucket.com/albums/pp343/Scottyman_01/Primer.jpg

Oh damn... good to know though.

I learned something new today!

Posted: 4/29/2012 2:54:11 AM EDT

[#26]

Pics of eye protection to drive the point home?

__________________________________________________________________
Cross-platform gun database/electronic bound book (v1.3.2) (and the original thread).
«nolite confidere in principibus, in filiis hominum quibus non est salus»

Posted: 4/29/2012 2:57:41 AM EDT

[#27]

Quoted:
Pics of eye protection to drive the point home?

__________________________________________________________________
Cross-platform gun database/electronic bound book (v1.3.2) (and the original thread).
«nolite confidere in principibus, in filiis hominum quibus non est salus»

None to be had unfortunately. Completely destroyed by a flying red dot lol

Posted: 4/29/2012 3:01:49 AM EDT

[#28]

Quoted:

Pmag ftw!

Yeah no shit! Makes me glad that I have mostly Pmags.

Posted: 4/29/2012 3:04:29 AM EDT

[#29]

Glad he is ok. I like my Bushmaster but would not buy one of that model. Im just unlucky so if something can go wrong, it would happen with me/ mine

Posted: 4/29/2012 3:05:08 AM EDT

[#30]

Quoted:

Quoted:

Pics of eye protection to drive the point home?

__________________________________________________________________

Cross-platform gun database/electronic bound book (v1.3.2) (and the original thread).

«nolite confidere in principibus, in filiis hominum quibus non est salus»

None to be had unfortunately. Completely destroyed by a flying red dot lol

The important thing is that he had them and isn't hurt.

Posted: 4/29/2012 4:06:22 AM EDT

[#31]

Way over Pressure. You can see the extractor ejector mark in the brass.

Posted: 4/29/2012 4:14:12 AM EDT

[#32]

Quoted:

Quoted:
A fully plastic rifle exploded. Color me shocked.

Lol a fully carbon fiber rifle fully exploded... Fully

as would have an aluminum gun...

Posted: 4/29/2012 8:34:08 AM EDT

[#33]

Quoted:

Quoted:
A fully plastic rifle exploded. Color me shocked.

Lol a fully carbon fiber rifle fully exploded... Fully

as would have an aluminum gun...

Adjust your sarcasm meter. I did find it interesting that it blew up a lot more than a standard receiver set normally does due to material difference. This could have been real bad.

Posted: 4/29/2012 9:06:40 AM EDT

[#34]

Quoted:
Way over Pressure. Youcan see the extractor mark in the brass.

That's the ejector, I believe. The extractor position is the part of the rim that's missing, hence the bent up extractor.

I don't see how a round could get so over pressured. Just an OOB firing wouldn't put the imprint of the ejector in the case head.

Not a huge fan of running hot rodded ammo in a gas gun. Bad stuff can happen. It can happen with regular ammo, too but not as likely. Glad the guy is ok. That would sure give a fella a flinch.

Posted: 4/29/2012 9:14:12 AM EDT

[#35]

Quoted:

Quoted:

Way over Pressure. Youcan see the extractor mark in the brass.

That's the ejector, I believe. The extractor position is the part of the rim that's missing, hence the bent up extractor.

I don't see how a round could get so over pressured. Just an OOB firing wouldn't put the imprint of the ejector in the case head.

Not a huge fan of running hot rodded ammo in a gas gun. Bad stuff can happen. It can happen with regular ammo, too but not as likely. Glad the guy is ok. That would sure give a fella a flinch.

Yup my bad

Posted: 4/29/2012 10:47:19 AM EDT

[#36]

Quoted:
http://www.hornady.com/assets/templates/site/images/superformance_pressurevsgas.JPG

Due to the longer duration of peak pressure produced by Superformance™, the post peak/declining port pressure at common carbine and mid-length gas port locations is still higher than that produced by standard propellant. This has a tendency to flood the system with a larger volume of gas, at a higher velocity, that tries to open the bolt of the gun too fast. It’s a timing issue. The cartridge case is still swollen from the application of pressure during firing while the gun is simultaneously trying to extract the cartridge case before it has had an opportunity to settle back to its original size, or more simply: the gun is still in the process or firing while it’s trying to extract the cartridge case.

Not blaming the Kaboom on the fact of the ammo being superformance. But Superformance is not meant for carbine gas systems. Tons of people have reported popped primers. But if the guy would have looked this up, he would never have bought the bad ammo in the first place and his gun would still be in one piece

On another note, there was a guy in the ammo section within the last 2 weeks with .308 superformance ammo piercing primers.

IF it rises to the level of a safety problem with catastrophic failure as a possibility, it's too hot for the commercial market. You can paste the shit out of the box with stickers that say "do not use this in X-length gas systems" and some fudd is going to put his half used box of shells from deer season sight in in a cup on his safe and give them away or use them later in an AR after he forgot what the box warned him not to do.

Posted: 4/29/2012 10:53:51 AM EDT

[#37]

You can keep your cheap plastic crap uppers, I still prefer steel or aluminum when little controlled explosions are going on near my face.

I don't think Bushie has ever had a good rep with their "carbon" uppers. Heck, a 6520 is plenty light if one wants a lightweight carbine.

Would it have ruined an aluminum one, maybe, but I'll bet it would have stayed together better.

Posted: 4/29/2012 11:00:45 AM EDT

[#38]

I'm thinking an Aluminum upper would have sprayed some pretty deadly shrapnel.

Posted: 4/29/2012 11:04:27 AM EDT

[#39]

Quoted:

IF it rises to the level of a safety problem with catastrophic failure as a possibility, it's too hot for the commercial market. You can paste the shit out of the box with stickers that say "do not use this in X-length gas systems" and some fudd is going to put his half used box of shells from deer season sight in in a cup on his safe and give them away or use them later in an AR after he forgot what the box warned him not to do.

Not sure if it's correct but somebody that reloads told me that's the reason I can't buy hot factory 30-06 ammo. Makes sense to me.

Posted: 4/29/2012 11:18:15 AM EDT

[#40]

Quoted:
Way over Pressure. You can see the extractor ejector mark in the brass.

This. Deep ejector imprint=very high pressure. Too much powder, bore obstruction,...?

Posted: 4/29/2012 11:28:16 AM EDT

[#41]

Quoted:

Quoted:
Way over Pressure. You can see the extractor ejector mark in the brass.

This. Deep ejector imprint=very high pressure. Too much powder, bore obstruction,...?

Possibly the complete opposite, too little powder.

I had a similar one a while back with a customers gun.
That was down to someone giving him a rogue round of ammo that detonated.
Separated case head and case stuck in the chamber were identical.
This one split he carrier though

Posted: 4/29/2012 12:02:52 PM EDT

[#42]

Note to self:

Do not allow Hornady Superperformance ammo to heat soak in a hot chamber before firing it. Doing so will likely result in dramatic overpressure.

Posted: 4/29/2012 12:12:42 PM EDT

[#43]

How'd you get the bruise on your hand?

Posted: 4/29/2012 12:21:11 PM EDT

[#44]

Quoted:
I'm thinking an Aluminum upper would have sprayed some pretty deadly shrapnel.

Aluminum uppers tend to just peel open a bit from every picture I've seen. Usually the mag gets fubard and the lower is fine.

Posted: 4/29/2012 12:31:10 PM EDT

[#45]

Quoted:

Quoted:
Way over Pressure. You can see the extractor ejector mark in the brass.

This. Deep ejector imprint=very high pressure. Too much powder, bore obstruction,...?

Possibly the complete opposite, too little powder.

I had a similar one a while back with a customers gun.
That was down to someone giving him a rogue round of ammo that detonated.
Separated case head and case stuck in the chamber were identical.
This one split he carrier though

Good point. There are a lot of powders out there that will detonate with too light of a charge. Don't know if Superformance is one or not.

Posted: 4/29/2012 12:34:22 PM EDT

[#46]

Quoted:

Quoted:
I'm thinking an Aluminum upper would have sprayed some pretty deadly shrapnel.

Aluminum uppers tend to just peel open a bit from every picture I've seen. Usually the mag gets fubard and the lower is fine.

I have a feeling that this kaboom was the same as the ones that balloon the upper and lower receivers of a aluminum AR and blow out the bottom of the magazine, but in this case the magazine was stronger then the receiver so the receiver went instead of the pressure going out the bottom of the magazine.

Posted: 4/29/2012 12:35:15 PM EDT

[#47]

Quoted:
the greatest part about this is the atacs hydroprinting

i would be fucking livid

I was thinking that too, that's expensive.

Posted: 4/29/2012 12:36:16 PM EDT

[#48]

Case head failure. Could be excessive headspace but I'm going with defective brass. If the webs are too thin, primers will be shucked or worse.

I would measure the thickness of the remaining case web. It will be significantly less than 0.180", measured from the part of the case which touches the bolt face and to the inside flash hole.

This part is the key: