Mini boom

[vluc]

MikieM, I did run a gen 3 barrel for several weeks, no problems. But like I said, I run the Gen 4 barrels for weeks sometimes months and I don't have the problem, then I do. 

[superdude]

Something to do, though it might not solve the mystery.

 

Check chamber support from your different barrels by dropping a round in and seeing, side-by-side, how much of the brass above the extractor groove is not supported by the chamber. Use new brass if you have it, maybe factory ammo and all from the same brand so you don't confound the appearance with different brass dimensions.

 

Some Glocks can/do fire out of battery, and as someone previously noted, the firing pin strike will be obviously off center. Yours looks okay in that regard. See figure 2 at this link:

 

https://www.ssusa.org/articles/2018/8/14/firing-out-of-battery/

 

I still suspect the brass. Crap like this does happen from time to time. Range pick-up brass is always suspect simply because you don't know its history. Kabooms aren't fun, and perhaps less fun when it happens if you're loading 9 Major.

 

https://www.ssusa.org/articles/2018/10/2/kaboom-the-consequences-of-a-blown-out-case/

 

 

 

 

[MikieM]

One other thing. Try a heavier recoil spring, say a 14 pound. If the gun is occasionally coming out of battery prior to being fired again this may be the culprit. 

With the current spring installed, cock the gun and hold it with the muzzle pointed up (unloaded, of course, but if you really want a surprise...). Gently push the slide towards the rear. Does it easily return?  Does the barrel shroud drop slightly?

The slide should come back to fully closed and the back of the barrel come back up with it.

 

I still believe, like superdude, that the brass and an unsupported chamber is suspect.

[superdude]

I'm not sure the unsupported barrel hypothesis is the problem. Sure, the Glock barrels don't support the case all the way to the extractor groove, but few barrels do. The case blowout in the link I provided was in a ramped barrel that provided enough case support support for 9 Major. In addition, other ammo with the same load were fired and they showed no signs of excess bulging in the unsupported region. Yet that one case still ruptured.  Bad brass will do that.

 

It never hurts to have more case support. That said, many of us have fired very high pressure loads in standard Glock barrels without incident.

 

The OP's load is within published load data so it does not seem to be the obvious culprit. The brass is the one thing that can't be easily ruled out. We don't know if its bad brass until something like this happens. Even new brass can be defective, though it would be rare. 

 

Edited to add: looking at case support will allow the OP to see if there are any differences in his Glock barrels. It might be useful, it might not, but at least he/she will have looked to see if there is anything obvious going on there. 

Edited November 2, 2018 by superdude

[vluc]

1 hour ago, MikieM said:

One other thing. Try a heavier recoil spring, say a 14 pound. If the gun is occasionally coming out of battery prior to being fired again this may be the culprit. 

With the current spring installed, cock the gun and hold it with the muzzle pointed up (unloaded, of course, but if you really want a surprise...). Gently push the slide towards the rear. Does it easily return?  Does the barrel shroud drop slightly?

The slide should come back to fully closed and the back of the barrel come back up with it.

 

I still believe, like superdude, that the brass and an unsupported chamber is suspect.

Planning to go up to a 15# ISMI anyway, appreciate the suggestion.  Gun cycles fine, everything moves as it should.

[rowdyb]

You got crap brass.

[Nevadazielmeister]

On 11/1/2018 at 8:10 PM, superdude said:

Probably time to invest in new brass. Old brass or questionable brass picked up at the range could be overused and weak.

 

Best to start with some new brass that you know the history of.  Brass, even paying for new brass, is cheap compared to the cost of an injury. 

 

My sentiments exactly. A lot of people argue over used versus new brass and in my hands, I want to know the history of the brass that contains enough energy to remove my hand. When the OP mentioned "good sting to the hands and powder blowing down through the trigger area onto my hands" I got worried he was injured. Glad he is okay. I also believe that hand inspecting the brass is not enough to confirm its safe usage, at least not at the levels of bulk we shoot. 

[jkrispies]

On 11/2/2018 at 10:10 AM, vluc said:

Planning to go up to a 15# ISMI anyway, appreciate the suggestion.  Gun cycles fine, everything moves as it should.

If you've had a gun that works well and recoils the way you like with your 13# spring, I personally wouldn't change the poundage as that will change how the sights track.  With as much experience as you have with this gun and load, that would be a downer to have to re-learn your gun.  Definitely consider replacing the spring, though, as all springs wear out and they should be replaced periodically anyway.

 

My guess--as others have guessed--is that you got some brass that was fired through a 9 Major, and you've since won the lottery 8 times.  Sucks, but it's that or pay for new brass.  FWIW, if I'm going to a big match I'll make an effort to use new (or certainly only once fired) brass so something like this doesn't happen... but it still sometimes happens.  At my last monthly match I had the exact same thing happen with a friggin' .22lr round.

 

FWIW also, one way to avoid 9mm Major left-overs and still use range pickup brass is to attend and get your brass from a steel match.  Trust me, you'll have 9mm galore, and the chances of somebody shooting 9 major on steel is almost zero.  There’s still a cgance youll get some as SC and USPSA shooters intermix, but I think the likelihood is significantly reduced.  

Edited November 3, 2018 by jkrispies

[vluc]

3 hours ago, rowdyb said:

You got crap brass.

LOL, I for sure got 8 pieces of crap brass, the other several thousand shot just fine.

 

Edited November 3, 2018 by vluc

[vluc]

2 hours ago, Nevadazielmeister said:

 

My sentiments exactly. A lot of people argue over used versus new brass and in my hands, I want to know the history of the brass that contains enough energy to remove my hand. When the OP mentioned "good sting to the hands and powder blowing down through the trigger area onto my hands" I got worried he was injured. Glad he is okay. I also believe that hand inspecting the brass is not enough to confirm its safe usage, at least not at the levels of bulk we shoot. 

Thanks, no, not injured save for my pride.  

[Red Ryder]

Thanks for the heads up. If I am R/Oing you, I will definitely give you some extra space. I don’t want to dig any metal out of my body. Other than upping that spring weight to 15lbs, I think you got weakened brass. Maybe crap spit out by those open CZ shooters! JK.

[vluc]

Well, Rob, you shouldn't have any worries on that, since you rarely, if ever, shoot with us anymore. 

[Eman]

On 11/1/2018 at 9:59 PM, HI5-O said:

Maybe some of that brass you collected was shot out of some 9 major open guns? I know some shooters who load used brass for lost brass matches. 

This was the first thing I thought after reading about where you picked up he brass. Stay away from 9 major brass. They can stretch out the base and your sizing die won’t catch it. 

[Sarge]

1 minute ago, Eman said:

This was the first thing I thought after reading about where you picked up he brass. Stay away from 9 major brass. They can stretch out the base and your sizing die won’t catch it. 

What??? I load 9MAJOR brass over and over and over.....

[EEH]

Sarge, do you use a case gauge.

[Sarge]

1 hour ago, EEH said:

Sarge, do you use a case gauge.

Hundo. I gauge every round off the press.

[jaep1911]

The same thing happened a few times in a short period of time when I was shooting in Limited with 40cal 200gr bullets. Many people said that the most likely cause was stressed brass. I changed the sizing die from a U-die to a Redding dual ring and the boom never happened afterwards.

[tires2burn]

Why would anybody sacrifice their body to shoot a GLOCK stymies me. There a too many examples like this to write it off for every reason under the sun except a unsupported chamber.

[vluc]

It's a 9mm, not a. 40. I've been shooting glocks for over 15 years and I have had eight, 8 instances, all this past season. 

[GJM]

I would run an OEM RSA.

 

In my Gen 4 34 CO pistols, I started having problems with failures to ignite. After a lot of messing with things, I figured out the 13 pound after market spring I was using was allowing my thumb to occasionally retatrd the slide slightly. In my case this could result in a FTF, but I could see how it could also allow what you are experiencing. Since the change back to OEM, zero problems. 

[vluc]

GJM, a very plausible explanation.  I have considered that given my grip.  Doesn't exactly explain why it has never happened when I shot production for years, nor did I have a single occurrence last season with the exact same gun(s), but beside bad brass, I can't see it being a barrel issue.

 

I've been reworking my grip over this off season so far, could very well be the culprit.  Finding I'm not keeping a consistent firm grip with the support hand.  Starts good, but I catch it fading away.  As I look back on the occurrences, always towards the end of a stage, never the beginning.

 

 

 

[9x45]

All semi auto pistols have some unsupported chamber, properly called the barrel ramp, otherwise they wouldn't function. And it did not fire out of battery as evidenced by the center primer strike. Also try to get a Glock to fire out of battery with a snap cap, won't do it. The most common cause of case rupture is using brass fired from an Open gun. Did your brass (not from a Glock) look like this before loading? 

[9x45]

I would also measure a few dozen bullet diameters to be sure. If there is not enough neck tension (interference fit between the bullet OD and the case ID) it can setback. More crimp will only increase the setback, not prevent it. 

[IHAVEGAS]

5 minutes ago, 9x45 said:

Also try to get a Glock to fire out of battery with a snap cap, won't do it.

 

Depends on how far out of  battery you mean, 1st one I picked up snaps at about 1/6" before the slide is full closed.  

[Absocold]

First, as has been stated repeatedly, check for setback / improper neck tension.

 

Next, ground your press. This is very important but very few people do it. An un-grounded press can build up a static charge. This, obviously, is bad for several reasons. I'll skip the conspicuous ones and point out that a static charge in the powder funnel area can cause powder grains to stick to the sides rather than falling into the case. A few flecks here, a few flecks there, unnoticed on a scale or from firing because each bit that didn't go in was tiny. But they add up. Then, you bump the press a little harder than usual and all those sticky grains fall. Now you have a bomb mixed in with the rest of your ammo. Anti-static spray can help. Running a dryer sheet through your powder drop before each session is good too. But everyone should ground their press.

 

Lastly, since everything else seems to check out, I'd suck it up and buy a new barrel. Yours may have been defective from the start. It's cheap peace of mind. And after 8 blowouts your feed ramp and chamber lip may have been damaged from debris or flame cutting which may aggravate the problem.