Catastrophic failure in my SA15.7 - A happy ending from Colt Canada

[Familygunnutz]

Totally different failure, different cause. In other words, irrelevant.

how so? I just want to say, I'm not picking fights, just curious.
see the link here for Colt USA verdict, please read the verdict on the second image.
what type of strange ammo defect can cause only a single point failure on OP's rifle?
http://www.bayoushooter.com/forums/...rdict-is-in-on-Colt-6920-Catastrophic-Failure

why can't colt Canada issues a engineers report on OP's Case?

 

[Stray03]

Love all these engineers we have here who can say that that damage couldn't happen due to ammo without even seeing the whole rifle. The fact that they can determine conspiracies just from 2 blurry pictures makes me understand why there are so many 9/11 conspiracies. I understand that this is the internet and that everyone is an expert, but unless you have physically inspected the rifle with the same access to methods the manufacturers have I figure shut up unless you can prove it.

So if you can prove that this couldn't happen due to ammo go for it, if not, just appreciate that the company has amazing customer service.

PS I am not a colt canada fan boy, Im too poor to own their toys and I am happy enough with my Norinco not to wish I owned one of theirs.
What I am, is fed up with the retards on here thinking they are smarter than they actually are. Prove your theory, or it is just an uneducated opinion and shouldn't be written. Reminds me of politicians.

 

[X-man]

OK,

Have a look at the .gif below.

Look at the pink "block" of the gas carrier key. Consider if the bolt was pushed to the rear with enough force to actually damage (bulge/balloon) the rear of the buffer that the bolt would have been pushed further to the rear than it is designed to...aso you see here in this picture.

Note. The charging handle should NOT be reciporcating with the bolt as it moves.

But, if the bolt carrier was driven back past where it should go, where is that pink piece (gas carrier key) going to go and what is it going to do? It's going to maybe get pushed back in a way that may cause an upward push by the gas carrier/key on the charging handle, pushing the upper receiver UP as the bolt exceeds it's normal rearward travel.

What's that UPward push going to do? Probably cause a failure exactly as we've seen in the OP's photo, and rip the rear takedown pin out.

I could be wrong, and I don't have an AR in front of me to look at the exact mechanics in person (I will tomorrow believe me!) but this *SEEMS* like a possible cause/effect relationship that could have caused the damage.

Well done to Colt Canada for standing behind your product and fixing a problem that wasn't even yours!

NS

I echo the above. As for those choosing to take a dump on Colt Canada based on nothing more than the chip on their shoulder, why not give it a rest? Constructive criticism is great, but I'm disgusted by the select minority within our community who only seem content when piling on one of our own. I dunno, perhaps they do so in order to compensate for some secret insecurity, but howsoever, it has gotten really old. I'm not a CC fanboy, but I can acknowledge great customer service and appreciate a manufacturer that stands behind their product.

 

[ricohman]

I think its awesome that CC actually posted their findings to this public forum.
I also think they take something like this extremely seriously and the engineers on hand would examine it to the point of determining exactly what happened.
They certainly have the resources to do so.

 

[Stray03]

As for the ammo itself and why it caused that level of damage, I am not sure. I have fired thousands of rounds over my 15 years in the Army and this was the most violent separation ammo failure I have encountered. Maybe it's the fact that steel doesn't blow out as easy as softer brass and thus the force is more noticeable, I really don't know as that's not my area of expertise. All I know is that it felt very different and it was a b!tch to get the casing out of the chamber.

-Saryet, out!-

Had the casing stayed intact? or did the head blow out?

 

[Saryet]

The case was far from intact. After I was able to extract it, there was a nice bulge and a split in it.

-Saryet, out!-

 

[tiriaq]

how so? I just want to say, I'm not picking fights, just curious.
see the link here for Colt USA verdict, please read the verdict on the second image.
what type of strange ammo defect can cause only a single point failure on OP's rifle?
http://www.bayoushooter.com/forums/...rdict-is-in-on-Colt-6920-Catastrophic-Failure

why can't colt Canada issues a engineers report on OP's Case?

Note the phrase "separated case head". Different situation.
Op did not submit any ammunition or expended cases.

 

[Stray03]

The case was far from intact. After I was able to extract it, there was a nice bulge and a split in it.

-Saryet, out!-

So the casing still had the base with the primer intact, but there was a bulge and a split? was the split running the length of the case or across it? Guess you don't have a picture of the casing?

 

[Stoner99]

Dont laugh but some ex spec forces look like that now... Doesn't mean they were not more badass than any of us could ever wish to be at one point in their life

Yeah just look at Brandon Webb AKA FAT WEBB! His book is great, to bad he is rubbing a little to close to CNN in all the wrong ways.

 

[Hitzy]

The rear hole does not take any recoil force on an AR as is is oval as opposed to the front hole that is round for fit tolerance on uppers. The carrier impact at the rear imparted a force in a direction the lug was never designed to take. There is no porosity, and the evidence (and there is lots) all points to an ammunition failure. There is no big conspiracy here folks.

So I guess this could be replicated with a short/out of spec buffer and regular SAAMI spec ammo? Or maybe a carbine buffer in a rifle tube and regular ammo?
It's the impact of the bolt key hitting the receiver ring, but there isn't even a mark on it? How did the key get past the charging handle to hit the receiver ring?

The resulting high pressure caused a very energetic opening. The bumper on the rear of the buffer was mushroomed and deformed and the key recoiled hard enough to contact the lower receiver at the top of the extension hole.

Maybe it's just me, but that buffer tube looks like it could go in another turn? None of my rifles have the buffer looking that far out, like it's ready to fall out.
Would that not also create the same situation where the carrier has too much travel, allowing it to hit the charging handle, and popping the rear lug?

 

[RobertMcC]

So I guess this could be replicated with a short/out of spec buffer and regular SAAMI spec ammo? Or maybe a carbine buffer in a rifle tube and regular ammo?
It's the impact of the bolt key hitting the receiver ring, but there isn't even a mark on it? How did the key get past the charging handle to hit the receiver ring?



Maybe it's just me, but that buffer tube looks like it could go in another turn? None of my rifles have the buffer looking that far out, like it's ready to fall out.
Would that not also create the same situation where the carrier has too much travel, allowing it to hit the charging handle, and popping the rear lug?

Good eye.

 

[barsik]

So I guess this could be replicated with a short/out of spec buffer and regular SAAMI spec ammo? Or maybe a carbine buffer in a rifle tube and regular ammo?

no, because the pressure isn't high enough
It's the impact of the bolt key hitting the receiver ring, but there isn't even a mark on it? How did the key get past the charging handle to hit the receiver ring?

again, no because of the length of the buffer/spring/carrier length. although the key is on top of the carrier, it will not contact the lower unless the extension has failed


Maybe it's just me, but that buffer tube looks like it could go in another turn? None of my rifles have the buffer looking that far out, like it's ready to fall out.
Would that not also create the same situation where the carrier has too much travel, allowing it to hit the charging handle, and popping the rear lug?

what do you mean, ready to fall out? it has perfect placement on the buffer retaining pin and it is also almost flush with the threaded section of the lower. any further and you would not be able to seat the upper in place.

looking at the buffer, one can see a half moon impression on it from the back of the carrier. that would have taken a lot of force.

 

[Hitzy]

what do you mean, ready to fall out? it has perfect placement on the buffer retaining pin and it is also almost flush with the threaded section of the lower. any further and you would not be able to seat the upper in place.

looking at the buffer, one can see a half moon impression on it from the back of the carrier. that would have taken a lot of force.

I mean the edge of the buffer is almost out of the buffer tube, doesn't look right to me...that's all.
Some buffers have a clear coat over the bare anodizing, and mark up like that from firing a single round....I have some that look like hell and some that look like new after thousands of rounds. Spikes looks like new still, the cheaper generic looking ones like in that Colt have full circles from the FA carriers. Doesn't indicate anything.

 

[Runningfool]

CGN is equal parts info and comedy. This thread is living proof of that!

 

[Runningfool]

I mean the edge of the buffer is almost out of the buffer tube, doesn't look right to me...

Looks fine to me. As Barsik said, what would you gain by turning in the buffer tube another turn except difficulty seating the upper?

 

[FLHTCUI]

There is no big conspiracy here folks.

Your kinda new here to CGN, some people jump to conclusion regardless of how well the Manufacturer
handled the situation and in this case You and Colt Canada did a great job.
Thanks for Posting the true results found and not some glassed over bs.
Rob

 

[Hitzy]

Looks fine to me. As Barsik said, what would you gain by turning in the buffer tube another turn except difficulty seating the upper?

Well I'm just going by what CC said caused the damage, the end of the buffer...poly part mushroomed which allowed the carrier to travel farther back then normal, so the gas key hit the receiver ring causing the lug to snap off. It's the result of the carrier having too much travel that made the lug snap. Couldn't something like a buffer tube not turned in enough allow for the same situation?
Nobody has taken a stab at answering me on how the key got past the charging handle to hit the receiver ring as CC suggested?

 

[Stray03]

Well I'm just going by what CC said caused the damage, the end of the buffer...poly part mushroomed which allowed the carrier to travel farther back then normal, so the gas key hit the receiver ring causing the lug to snap off. It's the result of the carrier having too much travel that made the lug snap. Couldn't something like a buffer tube not turned in enough allow for the same situation?
Nobody has taken a stab at answering me on how the key got past the charging handle to hit the receiver ring as CC suggested?

Figured you had figured out that the part of the gas key that is bolted on the bolt actually passes below the charging handle, and therefore would contact the lower receiver before the upper part of the key hits the handle.

 

[Stoner99]

I don't think Colt Canada is stretching anything here case is closed.

 

[Hitzy]

Figured you had figured out that the part of the gas key that is bolted on the bolt actually passes below the charging handle, and therefore would contact the lower receiver before the upper part of the key hits the handle.

Yeah, I realize now that was poorly worded on my part. My bad.
The rear of the key is square, steel, and would have the same force imparted on the upper receiver by hitting the buffer tube face/receiver ring as firing the rifle would, straight back, nothing up/down in the lug area.... It would also leave a mark somewhere in that area if it hit there 30 times I would think.
The 45 bend on the key hitting the charging handle was what I was thinking would be the only way enough upward force could be applied to snap the lug off, but I don't see how that would be possible at all.
Anyway OP got a new upper, not hurt, CC stepped up which is pretty good considering the rifle had been modded out of the box and was not in original configuration, lots of manufacturers would deny based on that alone. I'm still not sure I buy the explanation of the ammo being the "sole" culprit, but whatever, happy ending for OP which is all that matters.