Blown case

[Sandspider500]

Sport pistol is .69g per cc or 10.6 grains per cc. 9mm case holds 13.3 grains of water and has .862 cc of space inside. So 10.6 x .862=9.1372 is a case full of sport pistol. A double charge of 8.4gr would be 92% of a full case in 9mm, or almost filled to the top.

[kcstott]

Sport pistol is .69g per cc or 10.6 grains per cc. 9mm case holds 13.3 grains of water and has .862 cc of space inside. So 10.6 x .862=9.1372 is a case full of sport pistol. A double charge of 8.4gr would be 92% of a full case in 9mm, or almost filled to the top.

Winchester 231 is about 1/4 a case full in a 9mm with a 3-4 grain load. you can easily double charge a case with 231.

[Sandspider500]

A 4gr charge of 231 is 43% of the case

[sofbak]

The blown case above was due to a double charge of W231. Blew the gun up.

You don't know anything about my shooting history or capabilities, so go shove it!

Dan

By the shape of the case failure and the location of the case failure, that one is a classic example of glock bulge/strain hardening followed by more strain hardening during the reload/resize process......

A double charge may have been the impetus, but the characteristics of the brass are indisputable....

Was that one of your reloads?

[ojisan]

I'm not picking on Glock here, but early G17s did bulge the brass badly and it was considered damaged and unsuitable for reloading.
The owners manual said to use only new FMJ ammo and never use reloads.
The G17 was designed as a military pistol using new FMJ ammo that was fired once and then the case was discarded.
Glock did increase the case head support for the 9mm, and then went through the cycle again with the S&W .40.
Note that there are case prep tools specifically made to iron out the Glock Bulge.
However, the bulge will look ironed out but that does not mean that all the stretched brass is back in the same place, there will be thick spots and thin spots, with the thin spots leading to case failure.
Any brand of gun can have this problem if someone gets too exuberant with a dremel on a barrel's feed ramp / chamber mouth and removes too much material.

[fish45]

That is all well and good, but the blowout pictured is not from an over-charge. It is from a case fired in an unsupported chamber that has bee weakened enough so that it finally gave out when fired again.

This is exactly what happened. Anyone arguing this is more than likely less experienced than they think they are. Is it possible its something else? Sure, we're only seeing a picture on the internet. But, its definitely from a glock, probably from a weak case.

For some reason people think new brass isn't subject to this either, it is. Brass makers make cases by the millions (if not billions). I don't get why theres such blind faith that every component of every round made is perfect.

[stormvet]

OP I’ve been shooting my reloads out of my Glocks for decades 9mm, 40 and 45. Well over 100,000 rounds and never have had a case failure while shooting my Glocks, I’ve reloaded some cases easily a dozen times.

I have had two cases failures while shooting both 9mm, one in a Just Right Carbine. My thoughts on that one it fired out of complete battery, no damage to the gun. The other happened two days ago, P80 Glock clone with a PSA slide, I do not think it was an over charge. A weak brittle case is my thinking on it or 124/147 bullet somehow got in my bag of 115s, blew out the mag but no damage to the gun.

Glock hasn’t had unsupported chamber issues for a very long time, it was an issue with the first two generations but not since. The PSA barrel has less support then a Glock barrel.

The truth is this is a risk we take when handloading, we can take all the precautions in the world and it can still happen.

[sofbak]

A, B, C

There's the answer to the the **** message I kept getting and this mid-20th century site's requirements THAT a post at least 3 characters in length. PHUC this antiquated forum! But still:

I'm not picking on Glock here, but early G17s did bulge the brass badly and it was considered damaged and unsuitable for reloading.

This. When a round is fired in an un-supported glock chamber, that brass is strain hardened around the perimeter of the un-supported area.


The owners manual said to use only new FMJ ammo and never use reloads.
The G17 was designed as a military pistol using new FMJ ammo that was fired once and then the case was discarded.
Glock did increase the case head support for the 9mm, and then went through the cycle again with the S&W .40.
Note that there are case prep tools specifically made to iron out the Glock Bulge.

Yes, but....in addition to resizing that bulged brass, it is additionally strain hardened where the bulge originally occurred.

However, the bulge will look ironed out but that does not mean that all the stretched brass is back in the same place, there will be thick spots and thin spots, with the thin spots leading to case failure.

It is the perimeter of the original bulge that is the concern and is the weakened area of the brass (without an annealing step.

Any brand of gun can have this problem if someone gets too exuberant with a dremel on a barrel's feed ramp / chamber mouth and removes too much material.

[TomReloaded]

Lol, it's not from it being a Glock.

I *routinely* fire the same brass, over and over until it splits, from my glock. Thousands of times. The brass splits at the case mouth after so many firings and i toss it.

Glocks shoot +p+ just fine, and have had plenty of support for a couple decades now. The unsupported chamber was a .40sw issue on early gen2 Glocks, and has long been resolved.

What happened was jhp's at 1.115. that's enough for some profiles to hang up and fire out of battery, which will absolutely blow the case out in the manner posted above. Shrink those things down to 1.100 max. Some data goes down to 1.060" for a jhp. Sometimes that's appropriate.

[eaglemike]

Lol, it's not from it being a Glock.

I *routinely* fire the same brass, over and over until it splits, from my glock. Thousands of times. The brass splits at the case mouth after so many firings and i toss it.

Glocks shoot +p+ just fine, and have had plenty of support for a couple decades now. The unsupported chamber was a .40sw issue on early gen2 Glocks, and has long been resolved.

What happened was jhp's at 1.115. that's enough for some profiles to hang up and fire out of battery, which will absolutely blow the case out in the manner posted above. Shrink those things down to 1.100 max. Some data goes down to 1.060" for a jhp. Sometimes that's appropriate.

The early G17 did have less support than later models, it wasn't just the .40's, although the .40's ended up having more issues.
I bolded above your part about firing out of battery due to COA - how would that happen? I've seen some G models fire out of battery, always due to wear, or using aftermarket parts (which often wear faster than OEM parts). Why would a longer COL allow/cause firing out of battery?
I used to shoot with a group that shot about 2K/week/person from various Glock pistols (17, 17L, 22, 24, 19) so have seen a few things happen.
Just curious about the firing out of battery due to COL.

[fish45]

They happen very seldomly but they still happen. In all likelihood it was a single piece of weak brass in an unsupported chamber.

[divingin]

A double charge of 8.4gr would be 92% of a full case in 9mm, or almost filled to the top.

Question: Is 92% capacity 92% of what the empty case will hold, or is it 92% of available case space taking bullet seating into account?

Not that I care all that much; my pistol loads are nowhere near full. Just wondering.

[TomReloaded]

The early G17 did have less support than later models, it wasn't just the .40's, although the .40's ended up having more issues.
I bolded above your part about firing out of battery due to COA - how would that happen? I've seen some G models fire out of battery, always due to wear, or using aftermarket parts (which often wear faster than OEM parts). Why would a longer COL allow/cause firing out of battery?
I used to shoot with a group that shot about 2K/week/person from various Glock pistols (17, 17L, 22, 24, 19) so have seen a few things happen.
Just curious about the firing out of battery due to COL.

Usually a extra long oal in a glock will jamb the mags and you get a FTF... except with already short and fat HP's, which will chamber, but jamb the rifling juuuust slightly, and a glock will fire very slightly out of battery. Its enough to get the case enough onto the ramp to expose the thinner part of the brass.

The specs required to be just enough out of battery to fire but still just enough to still chamber are pretty narrow, but it happens right in that oal range.

[kcstott]

Question: Is 92% capacity 92% of what the empty case will hold, or is it 92% of available case space taking bullet seating into account?

Not that I care all that much; my pistol loads are nowhere near full. Just wondering.

No idea on a pistol cartridge but on a bottle neck rifle case it's to the beginning of the neck. I would assume on a pistol case it's where the bullet would typically stop when seated. hence my comment on a 3-4gr charge of 231 in a 9mm being about 1/4 full. that my eye and from the top of the case, now if you take the bullet seat depth into account I could see that being 43% of case cap.

[jaborni]

It happens. I've had that happen with virgin brass and reasonable powder charges. I've had that happen with factory loads too.

If i had to guess why exactly, i'd say it has something to do with the powder not cooking off at the right time , like a hiccup that causes a bunch of back pressure or something. Could be a weak point in the brass too.