9mm case head blowout

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someguy2800

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Had this happen today and I thought it was interesting enough to share. I was shooting my 9mm 1911 and on this round I felt a bunch of particles hit my face and lighter than normal recoil. The case was still in the extractor and jammed between the slide and the rear face of the barrel. No damage to the gun or anything else. I believe it was a defective case but maybe something caused an overpressure. Was loaded on a progressive press with a powder lockout so an overcharge is unlikely. I believe it was just a defective case.

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Glad you're OK, someguy2800.

Dont know if this could be a contributing factor, but I notice the lack of a feed ramp on the barrel. The only 9mm 1911 I've dealt with, 1911 Springfield Range Officer, had a fully supported, ramped barrel. I've never saw any bulge even with +P from that.

Dave
 
Glad someguy is okay.
Anyone know where PMC brass is made?
SO much bad 9mm brass out there, be careful.
 
Glad you're OK, someguy2800.

Dont know if this could be a contributing factor, but I notice the lack of a feed ramp on the barrel. The only 9mm 1911 I've dealt with, 1911 Springfield Range Officer, had a fully supported, ramped barrel. I've never saw any bulge even with +P from that.

Dave

This is like a 1985 production springfield armory 1911 so it is an un-ramped frame with a remsport match barrel in it. It has quite a bit of unsupported chamber.
 
This is like a 1985 production springfield armory 1911 so it is an un-ramped frame with a remsport match barrel in it. It has quite a bit of unsupported chamber.
I’d be wary of range pickup brass in that particular gun/barrel.
 
Was loaded on a progressive press with a powder lockout so an overcharge is unlikely.
I’ve had this happen as well. What was your load data?
In my case, I was loading 115gr LRN with titegroup, and I wasn’t at max data but misread the COL and it should have been 1.100 and I loaded at 1.090. I ended up pulling the rest and made sure the COL was correct for the next batch. I do not believe mine was a brass issue, and I’ve loaded a lot of PMC brass along with just about every other headstamp without a problem.
 
I’ve had this happen as well. What was your load data?
In my case, I was loading 115gr LRN with titegroup, and I wasn’t at max data but misread the COL and it should have been 1.100 and I loaded at 1.090. I ended up pulling the rest and made sure the COL was correct for the next batch. I do not believe mine was a brass issue, and I’ve loaded a lot of PMC brass along with just about every other headstamp without a problem.

It is 5.0 grains of powerpistol with a 124 gr RMR fmj rn. COAL is 1.170. I've shot a few thousand of this load in this pistol and others.
 
Yeah, there's just no help from that barrel if the brass starts to move. My understanding is that PMC is generally consider pretty good 9mm brass. If you're sure your load was within spec (and the lighter than normal recoil suggests it probably wasn't some massive overcharge), then it's hard to figure out what lesson to draw from this.
 
Yeah, there's just no help from that barrel if the brass starts to move. My understanding is that PMC is generally consider pretty good 9mm brass. If you're sure your load was within spec (and the lighter than normal recoil suggests it probably wasn't some massive overcharge), then it's hard to figure out what lesson to draw from this.

Yeah that's the same conclusion that I came to. I can see nothing else abnormal about the brass or primer or anything else and I have fired thousands of rounds from this handgun so I am going to shrug and carry on.
 
A very unsatisfying answer, but sometimes it's all you can do.

On the plus side, you now know that the gun offers a pretty good level of protection to you in a case blowout! Good old steel frames are nice that way.
 
Anyone know where PMC brass is made?
SO much bad 9mm brass out there, be careful.
PMC is manufactured in S Korea by Poongsan Corporation which is a major munitions supplier to their military. Their ammo and cases are of very high quality.

Interestingly the case head marking "PMC" doesn't have anything to do with the words Poongsan or Corporation. It stands for Precision Made Cartridges
 
This is like a 1985 production springfield armory 1911 so it is an un-ramped frame with a remsport match barrel in it. It has quite a bit of unsupported chamber.
And that was part of the problem, no doubt. Pressure, non support, possible fatiged brass, possibly a defect in the brass, perhaps it was someones leftover 9MM Major (See fatigue again) case.
 
The 9mm is loaded hot compared with 45 ACP, 44 Special, and the wonderful 38 Special. I could not find the old "Speed Kills" videos that I had to watch in driver's education, this modern video just does not have the gruesome, mangled corpses that the old 8mm home projector films had:



When you are dealing with cartridges, the higher the pressure, the faster things go out of whack.

Have you extracted unfired rounds and noticed the cartridge OAL has shortened?

My RIA in 45 ACP, for whatever reason, ejected unfired rounds are shorter. Bullets are being pushed into the case as they are chambered. Recently I had a blown case head, with a 230 FMJ 7.8 grains AA#5, looked exactly like yours. Which chronographs just at 800 fps. That is a bottom end load. The event blew out the magazine base. I was able to clear the pistol, load a different magazine, and keep on shooting. The blast did crack my beautiful double diamond grips. And at the next session, where I absolutely made certain that the ammunition was loaded cautiously, I had a pierced primer with 230 FMJ 7.5 grs AA#5, load retort, and very hard recoil.

I believe my pressure problems are due to the bullet being seated in the case and increasing pressures. That could be your issue.
 
Setback... that's definitely a possible contributing factor. The only overpressure event I (think I) ever experienced involved brass that I learned had lost all neck tension, and was almost setback driven. I'm not aware of PMC 9mm brass being known for setback, but maybe doing the bullet-push test against the bench for other PMC cases loaded in that batch would be prudent.
 
The 9mm is loaded hot compared with 45 ACP, 44 Special, and the wonderful 38 Special. I could not find the old "Speed Kills" videos that I had to watch in driver's education, this modern video just does not have the gruesome, mangled corpses that the old 8mm home projector films had:



When you are dealing with cartridges, the higher the pressure, the faster things go out of whack.

Have you extracted unfired rounds and noticed the cartridge OAL has shortened?

My RIA in 45 ACP, for whatever reason, ejected unfired rounds are shorter. Bullets are being pushed into the case as they are chambered. Recently I had a blown case head, with a 230 FMJ 7.8 grains AA#5, looked exactly like yours. Which chronographs just at 800 fps. That is a bottom end load. The event blew out the magazine base. I was able to clear the pistol, load a different magazine, and keep on shooting. The blast did crack my beautiful double diamond grips. And at the next session, where I absolutely made certain that the ammunition was loaded cautiously, I had a pierced primer with 230 FMJ 7.5 grs AA#5, load retort, and very hard recoil.

I believe my pressure problems are due to the bullet being seated in the case and increasing pressures. That could be your issue.


It sounds to me like you might have a neck tension problem. What is the ID of a sized case from your sizing die before it goes in the expander?

In my case yes bullet setback is something I do check for and I also use a factory crimp die. This charge weight is a starting load. Its the load I shoot when I shoot IDPA.
 
No idea. Came in a bag of range brass
Keep in mind that increasing number of 9mm Major brass shot as USPSA major power factor rounds will find their way into mixed range brass supply as match shooters do not mark these brass and will leave them on the floor/ground after firing.

These brass can experience overly expanded case wall, particularly at case base area and if case wall is thinned/weakened, can experience case wall failure/blowout.

Like 40S&W brass, we may have to resort to not loading higher than mid-to-high range load data to prevent this if incident numbers increase.

Be careful.

Setback... that's definitely a possible contributing factor.
Very good point as when using less than max load data powder charge, a significant bullet setback can increase pressure past the max pressures in a hurry.

This is why I did the myth busting on neck tension and bullet setback and now only use brass/bullet combination that does not produce significant bullet setback - https://www.thehighroad.org/index.p...neck-tension-and-bullet-setback.830072/page-4
 
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Keep in mind that increasing number of 9mm Major brass shot as USPSA major power factor rounds will find their way into mixed range brass supply as match shooters do not mark these brass and will leave them on the floor/ground after firing.

These brass can experience overly expanded case wall, particularly at case base area and if case wall is thinned/weakened, can experience case wall failure/blowout.

Yet another reason to case gauge rounds. 9 major brass that has been heavily stressed (either because it is monstrously over pressure, or because it has been overloaded a few times) usually gets expanded at the base - where regular sizing dies cannot reach. That brass will then not pass a case gauge, even though it will easy pass a "plunk test," particularly in a barrel with generous clearances around the base like the OP's.

I continue to maintain that the punk [edit: PLUNK] test is for setting up COAL, and case gauging is a more exacting a reliable QC check on finished rounds.
 
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My blow out was either in a DW or SA 1911 - it’s been too long ago to recall, but both have a bit of unsupported case near the rim. At the time I thought it was over pressure due to Titegroups nature since I had measured setback and it was minimal. The case was a nickel plated Speer and most likely left by the local LE as they shot at our range.
Perhaps the cause was a defect in the case itself. When they manufacture giga-tera-peta-exa cases per year, at some point statistically speaking there will be a defect. Maybe most are hidden defects that never surface due to where on the case it is and within a supported chamber. Aren’t metal guns nice to have?
 
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