[vmr357]

A friend and I went shooting the other day. We shot our pistols, no problem. Then he wanted to try his new upper he got from a local builder. He shot a mag, then handed the rifle to me with a new mag. I fired several rounds then PFFFT and a cloud of smoke. The gun was locked up. The charging handle wouldn't budge. We packed up and he took the rifle to an armorer he knew who dug out a split case and a broken extractor. He said it was Federal .223 rem 55 grain FMJ Walmart box.

 

[Texas Guy]

What was the bolt? The extractor broke and wedged into the case


Sent from a distant planet far far away

 

[Sgt. Y]

The last box of Federal anything was some 22lr for my wife and it was crap had so many squibs I was afraid the lead was stuck in the barrel.

For practice shooting I use PMC Bronze .223 burns cleaner good quality brass and never had a bad round in all I have shot of it.

For my AR I bought a Toms Tactical BCG, very good quality they specialize in them, the bolts are shot peened and magnafluxed. Always best to source your parts from quality. My neighbor bought a Spikes upper despite my objections and that thing is junk. He has had it to my house a dozen times because parts were flying apart inside, starting with the forward assist to the bcg. All this Obama era parts and assemblies and the run on ammo decreased the quality all around.

 

[vmr357]

What was the bolt? The extractor broke and wedged into the case

Not my rifle, so I don't know what was in it. It was locked up tight. The report I got the next day was that it took over an hour to break it down and clean it up.

I figure life is too short for a cheap, ugly gun so I've got a DDM4v7. I would appreciate any ammo recommendations. I'm more a handgun guy than a long gun guy. I've got some PMC Bronze .223, PMC X-Tac 5.56, and thought I'd try some American Eagle 5.56 XM193. Anything else anyone would recommend?

 

[dsk]

I won't buy any of the black-box Federal 5.56 ammo anymore. I've encountered poorly-crimped bullets and once had a bullet telescope back into the case during feeding. Fortunately when the primer went off the powder simply caught fire and made a mess inside the action, since the bullet had fallen back inside the case. I don't understand how a company that makes premium quality handgun ammo like HSTs and Hydra-Shoks can mess up and make some really crappy 5.56 and .22LR ammo.

 

[huntershooter]

For inexpensive range ammo (55 gr) I use Wolf Gold, in addition to PMC Bronze.
Never had a problem.

"Toolcraft" makes a heck of a good BCG- that is reasonably priced.
I've used them in recent builds.

 

[Sure1]

I won't buy any of the black-box Federal 5.56 ammo anymore. I've encountered poorly-crimped bullets and once had a bullet telescope back into the case during feeding. Fortunately when the primer went off the powder simply caught fire and made a mess inside the action, since the bullet had fallen back inside the case. I don't understand how a company that makes premium quality handgun ammo like HSTs and Hydra-Shoks can mess up and make some really crappy 5.56 and .22LR ammo.

Wow I'll stick to PMC.

 

[wccountryboy]

Not my rifle, so I don't know what was in it. It was locked up tight. The report I got the next day was that it took over an hour to break it down and clean it up.

I figure life is too short for a cheap, ugly gun so I've got a DDM4v7. I would appreciate any ammo recommendations. I'm more a handgun guy than a long gun guy. I've got some PMC Bronze .223, PMC X-Tac 5.56, and thought I'd try some American Eagle 5.56 XM193. Anything else anyone would recommend?

While better ammo surely won't hurt, you're ASSUMING that the ammo was the cause of this event. An out of spec chamber could have caused the stuck case.

Until you've identified the cause, any remedy is just speculation.

 

[vmr357]

While better ammo surely won't hurt, you're ASSUMING that the ammo was the cause of this event. An out of spec chamber could have caused the stuck case.

Until you've identified the cause, any remedy is just speculation.

Good point. The rifle has been in use before and run without problems, but we are making an assumption about the ammo. I'll remind my friend of that fact.

 

[ktmoutlaw]

So the interesting question becomes how do you confirm chamber specifications? I know of only one tool from a place called Michiguns that even looks common person usable, let alone this only answers the 556 vs 223 question. I joined these forums looking for the answer to this exact problem! But, seeing it's not OP rifle doubt it's going to get resolved and posted. Good luck

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[wccountryboy]

Good point. The rifle has been in use before and run without problems, but we are making an assumption about the ammo. I'll remind my friend of that fact.

Stuck cases (the base cause of the problem) can be caused by out of spec ammo, out of spec chambers, poorly or uncoated chambers, bad extractor, fouling, or heat... often a combination of many of these factors.

 

[ktmoutlaw]

Well since this is a forum and my only credibility is based on my replies I would like to start an open discussion based on the picture that was shown the casing was ripped apart by the extractor which appears to have been separated from the bolt. I would like to see each of the above listed things that could have led to something other than an out of spec chamber. If we are talking out of spec ammo does that mean it's loaded too hot has incorrect projectile dimensions? My goal would be to collaborate and get a sticky thread to show how to properly diagnose this occurrence.

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[wccountryboy]

Well since this is a forum and my only credibility is based on my replies I would like to start an open discussion based on the picture that was shown the casing was ripped apart by the extractor which appears to have been separated from the bolt. I would like to see each of the above listed things that could have led to something other than an out of spec chamber. If we are talking out of spec ammo does that mean it's loaded too hot has incorrect projectile dimensions? My goal would be to collaborate and get a sticky thread to show how to properly diagnose this occurrence.

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The case became stuck. Based on the pictures, the cause was NOT a bad extractor. Had the extractor broken or slipped off the case, leaving the brass relatively undamaged, the extractor may have been the culprit.

So the question becomes: what caused the case to stick, to the point that the rim was ripped off and the extractor broken?

- Out of spec ammo. Either an overcharge that swelled the brass to the sticking point, or brass that was too soft and over expanded. Given the "pffft" reported by the OP, overpressue seems unlikely, though the bolt tried to go rearwqrd, with enough force to break the extractor and dqmage the case. Improper case dimensions could be a cause.

- Heat. Less than 60 rounds fired, so probably minimal impact

- Fouling. This assumes that the upper has been used before, and not cleaned.

- Poor chamber coating. If the surface of the chamber doesn't hqve a smooth surface, the brass can bind to it, causing a stuck case. The same principle applies to an out of spec chamber.

Most likely a combination of contributing factors. Even with good ammo, a bad chamber, some fouling, and heat could cause a stuck case.

 

[ktmoutlaw]

So the high school scientist in me would like to see the same weapon firing again and to see if the problem could be replicated. Also if some of the ammunition used is still around to try and remove that from the equation. I still think the chamber could be 223 not 556. Bringing the ammo in question if it was 223 or 556.

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[wccountryboy]

Tough to do. IF the cause was a bad round, you could fire 10k rounds of the same ammo and not have a problem.

A gunsmith can evaluate both the chamber cut and coating. Heat and fouling failures are somewhat random, and may or may not be easily repeatable.

 

[1saxman]

Also, it had to go 'bang' and then 'pfft' because the bullet was gone before the gas hit the bolt and the extractor pulled on the case. Because the case stuck, the extractor ripped it open before breaking. I say it must have been that way because no mention was made of the bullet stuck in the barrel, so it was not a 'squib' round but a full-power one.
I have to guess that the chamber in that barrel is a .223 instead of a 5.56, or is otherwise a tighter than normal chamber where the dirt from a few rounds jammed it.
Either way it doesn't sound like anybody tore down the new upper and gave it a thorough cleaning, inspection and lube before shooting it.
I suspect there is a problem of some kind in that upper; either in the chamber or the headspace.

 

[havanajim]

...

- Fouling. This assumes that the upper has been used before, and not cleaned.

....

Naturally, I have no idea what factors were involved here, but I have seen similar occurrences. In those cases, the culprit has been a switch in ammo from steel-cased to brass. The fouling generated by the steel-cased stuff is substantial compared to brass, since the seal with the chamber is not as tight as with brass. No issue at all if all that is shot is steel. However, upon switching to brass without a thorough cleaning, the case locks in tight into the fouling. Typically, the extractor rips the head off the case. But I imagine that a weakened extractor might also fail. Again, no clue of what the variables were here, but it does look familiar.

 

[BBBBill]

So the interesting question becomes how do you confirm chamber specifications?...

A chamber cast using Cerrosafe is a common practice. A bit tricky on an assembled upper, but doable with some forethought.

 

[screwtape.460]

Not my rifle, so I don't know what was in it. It was locked up tight. The report I got the next day was that it took over an hour to break it down and clean it up.

I figure life is too short for a cheap, ugly gun so I've got a DDM4v7. I would appreciate any ammo recommendations. I'm more a handgun guy than a long gun guy. I've got some PMC Bronze .223, PMC X-Tac 5.56, and thought I'd try some American Eagle 5.56 XM193. Anything else anyone would recommend?

I shoot surplus US military ammo through my AR platforms.Lakecity is the best but ive gotten good ammo regardless of the arsenal or country of origin everytime ive bought surplus nato ammo....m855 or xm193 in sealed 200rd packs.

 

[The Heater]

In fifty years of shooting all types of guns and all brands of ammo, the only pfft, I ever encountered was military surplus from the 1950s and someone else's reloads.
I've never had commercial factory ammo do that. I have had some 22s of various brands, just fail to fire at all. The only sound was the hammer falling or firing pin striking the back of the case. A dud if you will.