Fun With Case Head Seperation

[Viggen]

A little bit ago I had a case head peel itself from the rest of the case while residing in a stock G35.

The event blew out the magazine nicely.

It seems that a once too many times piece of well glocked brass decided to give up the ghost. Like I said, it blew out the magazine, put the extractor into orbit, and my hand was numb for a while.

There looks to be no detectable injury to the slide or frame, no cracks, and once I replaced the extractor it shot just fine.

This is the first time that's happened to me, in a semi-auto, although I have seen it happen several times before - to Sigs, Glocks, and SVI/STI types. I once had the same thing happen with a revolver with a 38 case but it didn't blow out the magazine......

It did end that days shooting session for me.

[AlamoShooter]

A little bit ago I had a case head peel itself from the rest of the case while residing in a stock G35.

This is the first time that's happened to me, in a semi-auto, although I have seen it happen several times before - to Sigs, Glocks, and SVI/STI types. I once had the same thing happen with a revolver with a 38 case but it didn't blow out the magazine......

<_<sounds like ? patern?,, maybe its not the guns.

[Viggen]

Well, not really.

I wouldn't exactly call a case seperation incident in a revolver that happened about 5 years ago and many tens of thousands or rounds ago, a pattern.

The only patteren I can see is that I keep shooting and that ever so often a case slips in that has been less than gently used.

But I know what you mean by patterns. I remember one guy who blew up two Sigs about a month and a half apart. But they that looked like a reloading error on his part. Neither gun survived his pattern.

[rwmagnus]

Viggen,

Any idea how many times you reloaded that case before it failed? Glad you weren't hurt. I bet you never got a magazine out of a pistol that fast before!!!

[eric nielsen]

For case separation, there are several things I would look at before I'd suspect repeated loadings of the same case. Here's a few:

-- Case was cracked before it was loaded & fired

-- Use of 200gr bullets in short 40

-- Use of Clays powder, N310 powder, WST, AA#2, etc

-- Lead bullets fired prior to jacketed bullets.

Other than the first item [cracked already] most causes of case separation can happen to a brand new case. Mostly they have to do with lots of [sudden] chamber pressure and not enough time and room for expansion for that pressure to go to.

[Viggen]

I managed to find the case head and later I pulled the rest of the case out with a multi-tool.

But right now I can't remembeer where I put them.

I want to check the make of the case but haven't gotten around to it.

My best guess is that, even thought the case did gauge, that there was a weakness or some crack down toward the base - I'm not running them short, with fast powders , or mixing bullet types.

And yes it was an explosive mag expulsion. That puppy came out right quick.

[AZ38super]

I have never owned a 40 cal gun and had not heard of case seperation until a couple months ago.

Since then I have seen 5 incidents and only one was in a Glock and it was the lessor of the 5.

Good thing you were not hurt and I think it tells everyone to pay more attention to cases when reloading.

[rwmagnus]

I managed to find the case head and later I pulled the rest of the case out with a multi-tool.

But right now I can't remembeer where I put them.

I want to check the make of the case but haven't gotten around to it.

My best guess is that, even thought the case did gauge, that there was a weakness or some crack down toward the base - I'm not running them short, with fast powders , or mixing bullet types.

And yes it was an explosive mag expulsion. That puppy came out right quick.

Okay then what powder and bullets weights were you running? Was it a brass or nickle case? Your original post indicated it was a stock gun so my guess (barring a reloading mistake) is it was a worn out case. Most Glock shooters don't run lead bullets although that debate continues. I have to think it was a case that was reused many times. Do you have a rough idea how many times you use a case before discarding them?

I'm an expierenced reloaded with just about every caliber but .40 S&W. Being a high pressure round you have to be even more careful. I'm still trying to get a feel for the life expectancy of these case.

[Joe D]

I did a non-scientific test a couple of years ago with some .40 cases and one of my G35s. I got up to the eight reload point and decided that was enough.I really was not seeing anything bad happening to the cases. The bulge was not getting any larger. My load was 4.3 gr of Titegroup with a 180 gr bullet.

As a rule I don't worry about it. .40 and 9mm brass is so cheap that I just buy one fired from Brassman and never pick it up. I do pick up one fired .40 when the Hoover PD uses our range.

[JFD]

A blown case head will most certainly end your shooting day.

Back when I was especially stupid and .38 Super Colts came with barrels that headspaced on the puny semi-rim, I managed to blow quite a few cases.

The last time it happened I had just handed it to someone to try. He fired one round and handed it back saying "how the hell do you shoot that thing???". At that time I noticed a chunk missing from the left-hand grip and the mangled mag on the ground. I kept that information to myself, called him a pansy, and bought a pair of those steel lined pachmyer (however the hell it's spelled) grips the next day. At the time I was trying to get 1700 fps out of a 88 gr. JHP. Amazingly, once I dropped down to published data, the cases quit blowing out .

My .40 routine these days is to buy "once-fired" brass, load it a couple or three times for practice, then leave it on the ground at the next match.

[Carlos]

Question for you: did the bullet on the round in question set back any before it seperated? I think it was likely a set back. .40 is known to be very sensitive to changes in OAL and we can think of a set back as "a radical alteration of OAL". I bet it was a set back. Of course, now that it happened, there will never be any way to tell.

I am guessing you are not using the Lee brand Undersized or small base resizing dies? If you are not using this die, it was probably a set back.

Sorry to read of your misfortune.

Edited December 27, 2005 by Carlos