What caused this? (Case rupture)

[ScorpioVI]

This happened in August of 2012 at my local range while I was the volunteer RSO. Didn't think much of it (technical details) at the time and just chalked it off to bad reloads, but I just started reloading a couple of months ago and would like a deeper explanation of why this happened and how to avoid it.

A couple came in with two Glock 17s and took two lanes. I had a full house and 3 other lanes to watch but I kept a close watch on the girl because she was very tentative, typical "oh gosh I'm just a helpless girl, won't you please load my gun for me" airhead. :-| Dude was all ate up, Barney-stance, can't hit ****. I noticed a few FTEs from the guy but chalked it up to limp-wristing, girl also had a couple of FTEs. On one of them the girl's G17 locked up completely, I had to yank the slide with all my strength to get the case out. Took a close look at the case, ruptured. G17 pretty much kaboomed, ejector bent, who knows what other damage inside, trigger won't reset. I started looking at all the other casings on the table and the floor, found another ruptured. Looked at the guy's table, found a bunch more.

I asked the guy where he got the ammo from, he had no idea, he "bought them over 10 years ago". Obvious reloads, they had marker stripes on them and different headstamps. The girl had the temerity to ask me what's the worse that could've happened. Really? I told them to pack it up and go see a gunsmith.

So what caused these cases to rupture like that. Old brass? Reloaded a few too many times brass?

[Mr. Gillious]

He didn't shake his ammo first

[HappyCamper781]

Loads were too hot AND/(or) not fully in battery when ignited. SOME early glocks had a reputation for this bout 10 or so years ago.

[Bastard]

improperly sized brass - fired out of battery

[thai562]

A really bad case of "glock bulge"
Hot load + unsupported chamber.

[jinjyr]

Does unsupported chamber mean the same thing as head spacing? Pardon my ignorance.

[twotacocombo]

I'm guessing OOB ignition as well, especially looking at the bulging at the base on cases 1,3 & 5. Strange how most of them have a nice clean horizontal tear at the same place. You figure these people would have stopped and looked after the first one ruptured and dumped hot gasses out the wrong end of the barrel.

[Germz]

A really bad case of "glock bulge"
Hot load + unsupported chamber.

he said this was a g17. there is no glock bulge on 9mm.

[Germz]

Does unsupported chamber mean the same thing as head spacing? Pardon my ignorance.

negative.

[Carcassonne]

You are from San Jose, so the range was in the Bay Area. I am guessing that the guy bought Load-X 9mm reloads at a gun show. My friend had some Load-X reloads from 10-15 years ago, and they did the same thing. Load-X sold a lot of ammo around the Bay Area at gun shows. There is a new owner now, so I don't want anyone to think the ammo they make now is bad. This was ammo made by the old/original owners.


P.S. What is a Barney-stance?


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[twotacocombo]

Does unsupported chamber mean the same thing as head spacing? Pardon my ignorance.

In short, Headspace is distance from bolt face to whatever keeps the cartridge from sliding down the barrel (rim, case mouth, shoulder, etc). An unsupported chamber is one that doesn't fully encase the cartridge where it wants to expand when fired. The feed ramp of older Glocks extended past the head, allowing a part of the body to expand into it.

[357magnum]

he said this was a g17. there is no glock bulge on 9mm.

I find bulged 9mm cases all the time at the range.
I bought the LEE undersize 9mm sizing die just for this reason.
I was having problems with the brass not fitting my chambers.
I have been loading 9mm for over 20 years now, and ran into this problem within the past 7 years or so.
No problems after using the LEE undersize die.
Any thoughts!
Thanks

[Carcassonne]

So what caused these cases to rupture like that. Old brass? Reloaded a few too many times brass?

Most likely too much powder or the wrong power which in turn would lead back to too much of the wrong powder: Over pressure

Sometimes a person shooting in competition will deliberately load their ammo over pressure. The case will bulge past the yield point of the brass which weakens it. The brass is scooped up after the match by the range staff and sold to a reloader. He doesn't notice it or doesn't care, and it gets used and sold. Then someone shoots it and it bursts even though it is within SAMMI pressure specifications. Usually in that case, all the brass doesn't look like that. It is usually 1 or 2 from a box.

Older Winchester brass was also garbage. If those are all Winchester brand, than it might be the poor quality of brass.




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[ScorpioVI]

P.S. What is a Barney-stance?

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Barney Fife? He used to hold that big revolver all shaky? Elbows bent, leaning back, stiff as a wet noodle.

Post a picture of the primers.
If the primer strike is off center, then it might have been out of battery explosion.

I don't have the cases anymore. This was a couple of years ago and I didn't take pictures of the primers.

[bigchinner]

been reloading for 15 or so years and have never had this happen. Thank goodness. I need my fingers and hands to scratch my butt.