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Posted: 4/25/2020 4:47:14 PM EDT
Firing a brand new 9mm this morning and I got a KaBoom.

The image of the cases shows the apparent issue was happening before it all went to hell. I finally got to the round that wouldn't take the pressure. I didn't notice any thing wrong as I was shooting. Only after it went boom did I check out the brass.

All the cases showed signs of bulging or a line (chamber edge I'm guessing). The KaBoom took out the extractor, blew the mag out of the well and took a chunk out of the lower.

The ammo was re-manufactured 147gr.

Comments appreciated as I get through this.

https://i1116.photobucket.com/albums/k578/DoubleSun1/IMG_4834.jpg
Link Posted: 4/25/2020 5:00:34 PM EDT
What kind of brand new 9mm?

Those cases look like they were producing very high pressures in an unlocked action.

Most, but not all 9mm pistols have a locked breech.  There are a very few that are blowback, though.
Link Posted: 4/25/2020 5:03:32 PM EDT
[Last Edit: 4/25/2020 5:04:22 PM EDT by DoubleSun]
Blowback - 9mm PCC

I'm trying to determine if it's the gun or the ammo. I'm not familiar with troubleshooting out of battery issues.
Link Posted: 4/25/2020 5:11:55 PM EDT
It could be an out of battery firing issue.  I have had a couple of 9mm ARs, and have handloaded some 147 grain loads towards the max end of listed data.

None of the cases looked anything like those, however.
Link Posted: 4/25/2020 5:19:18 PM EDT
[Last Edit: 4/25/2020 5:19:51 PM EDT by DoubleSun]
I'm hoping that someone seeing the image would chime in with "classic example of X".

It's a closed bolt with factory stock trigger. I was sighting in and setting up for the shot. Nothing quick.

All rounds ejected, amazingly when you see the image, until the last catastrophic failure.
Link Posted: 4/25/2020 5:20:09 PM EDT
What is that streak in the brass on the fired cases?  Looks like the cases were not supported. It starts out with slight brass deformation until you get to the point that the case head was unsupported and blew out at the head.

If the kaboom happened be fore the breech closed, how did the firing pin go forward when the breech was unlocked?

Are the case lengths correct? Not allowing the breech to close. Then see above comment.

Are cases sizes correctly so they don’t stop prematurely?  Theres still the issue of unlocked breech. And did the firing pin get stuck in a protruding position and set the primer off prematurely

 


Link Posted: 4/25/2020 5:28:50 PM EDT
[Last Edit: 4/25/2020 5:29:20 PM EDT by DoubleSun]
It's blowback, non-locking.

I think the streak is the chamber edge????

There appears to be a portion on the bolt/chamber interface that leaves a bit of the case unsupported. Not sure how much though. Can a 9mm round typically withstand not being fully supported if this were the case?


Link Posted: 4/25/2020 5:32:05 PM EDT
Getting called away - dammit. Gotta go.
Link Posted: 4/25/2020 5:34:10 PM EDT
Can a 9mm round typically withstand not being fully supported if this were the case?  
View Quote


Yes, it can.  But there are limits of course.

I think you have a gun firing out of battery, but I don't know why.

Worth checking the firing pin.
Link Posted: 4/25/2020 5:35:00 PM EDT
I had a similar problem.  I fixed it with a heaver buffer.

7.5  oz pistol buffer and a heavy hammer spring... and quit shooting remaufactured ammo
Link Posted: 4/25/2020 6:35:36 PM EDT
From my experience:

The risk of a Kaboom is more likely with re-manufactured ammo. Many Kabooms are in fact
as a result of re-manufactured ammo, they are cheaper for a reason from the Kabooms I
have seen...

Then there is non locked breech chambers with high pressure ammo like the 9mm Luger
cartridge (over 30K PSI)...

Finally, there are unsupported chambers using high pressure ammo like the 9mm Luger.
I personally don't trust the combination of the above...

If one is shooting a straight blow pistol or carbine/rifle be sure the bolt/recoil spring are
plenty strong/stiff...

I certainly prefer a delayed blow-back or locked breech pistol/rifle whenever possible
and certainly one with a supported chamber.


Good luck.

Link Posted: 4/26/2020 10:12:50 AM EDT
I certainly prefer a delayed blow-back or locked breech pistol/rifle whenever possible
and certainly one with a supported chamber.    
View Quote


As do I.  However my AR 9mm carbines have been plenty capable of handling +p type loads.

Even some that bulged brass in my P226.  Loads were worked up carefully, and the AR does better, the locked breech P226 exhibited case bulges way before the AR did.  Out of a sense of prudence, I didn't even try the hottest loads in the P226.

Not that either one is weak.  Just that those particuliar handloads were too high in pressure for the SIG, but not the AR.

Link Posted: 6/1/2020 6:07:38 PM EDT
[Last Edit: 6/1/2020 6:08:53 PM EDT by brickeyee]
ZAMAK frame and a fixed steel barrel.
The slide was steel and VERY chunky and heavy for such a small pistol.

The brass he showed me was NOT reloadable.
Not as bad as the ones here but rather 'interesting' looking.
Case mouths badly flared out.

The only thing I thought of at the time was "That thing is
opening under a lot of pressure."
He did complain it seemed very loud to him, but I doubted
he had a good 'calibration level' being an inexperienced shooter.

His muffs are not anything I would have trusted my hearing to even then.
Lightweight ear canal type muffs with a plastic frame supplying all the sealing pressure.

I would be surprised if they made 25 dB, even back then.
Around $15 or so at the time.
Link Posted: 6/10/2020 4:03:10 PM EDT
The #1 cause with reman ammo is reman ammo. Shitty quality control leads to out of spec ammo.

I think I would start "plunk" testing any rounds you have left. Make sure they all fit into the chamber fully.
The thing with 9mm is it is a tapered case. You can't properly resize it by using a conventional resizing die. Unless the brass is processed with a roller type resizer you will leave a bulge at the bottom of the brass that can and will stick in a tight chamber. If you dropped the hammer on one of those rounds you would end up with an OOB discharge.

The fact that you have many rounds that look like that before the actual case blowout would lead me in that direction.
I can't really see any of the primers but the profile of the round in the center doesn't seem to show evidence of primer flow or cratering that is common with high pressure conditions.
Link Posted: 6/10/2020 4:18:01 PM EDT
I am going to chalk this one up to the Chinese Corona Virus. We are now well over 100k.

Press F for respect...
Link Posted: 6/21/2020 9:02:50 PM EDT
Looks like 9mm firing in a .380 chamber.
Link Posted: 7/13/2020 3:03:31 PM EDT
I had a similar kaboom in a 9mm straight blowback AR-style PCC. It was happening because the case was deforming as it entered the chamber, due to there being no feed ramp before the barrel. The cases were being jammed into the barrel, sometimes deforming the bullets and sometime slightly deforming the brass. All it took was one that was deformed enough to not adequately enter the chamber fully. Thankfully, only the base plate on the magazine blew out with no damage to the gun (or to me!).

I fixed the issue by installing one of these: https://taccom3g.com/product/taccom-glock-lower-feedramp/

Manually cycle through a few rounds and inspect the cases/bullets for deformation to see if you're experiencing a similar issue.
Link Posted: 7/15/2020 4:47:46 PM EDT
Originally Posted By DoubleSun:
Firing a brand new 9mm this morning and I got a KaBoom.

The image of the cases shows the apparent issue was happening before it all went to hell. I finally got to the round that wouldn't take the pressure. I didn't notice any thing wrong as I was shooting. Only after it went boom did I check out the brass.

All the cases showed signs of bulging or a line (chamber edge I'm guessing). The KaBoom took out the extractor, blew the mag out of the well and took a chunk out of the lower.

The ammo was re-manufactured 147gr.

Comments appreciated as I get through this.

https://i1116.photobucket.com/albums/k578/DoubleSun1/IMG_4834.jpg
View Quote


Almost looks to me like the chamber could be short or otherwise out of spec as to prevent the rounds from fully chambering. If there was something preventing the round from chambering, the build up would start pushing subsequent rounds further & further back. I’d start with checking headspace.
Link Posted: 8/21/2020 3:45:42 PM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By mace2364:


Almost looks to me like the chamber could be short or otherwise out of spec as to prevent the rounds from fully chambering. If there was something preventing the round from chambering, the build up would start pushing subsequent rounds further & further back. I’d start with checking headspace.
View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By mace2364:
Originally Posted By DoubleSun:
Firing a brand new 9mm this morning and I got a KaBoom.

The image of the cases shows the apparent issue was happening before it all went to hell. I finally got to the round that wouldn't take the pressure. I didn't notice any thing wrong as I was shooting. Only after it went boom did I check out the brass.

All the cases showed signs of bulging or a line (chamber edge I'm guessing). The KaBoom took out the extractor, blew the mag out of the well and took a chunk out of the lower.

The ammo was re-manufactured 147gr.

Comments appreciated as I get through this.

https://i1116.photobucket.com/albums/k578/DoubleSun1/IMG_4834.jpg


Almost looks to me like the chamber could be short or otherwise out of spec as to prevent the rounds from fully chambering. If there was something preventing the round from chambering, the build up would start pushing subsequent rounds further & further back. I’d start with checking headspace.



Broken off piece of mouth of shell?
Link Posted: 8/21/2020 3:59:34 PM EDT
[Last Edit: 8/21/2020 11:33:54 PM EDT by KarlSG1]
Are there projectiles stuck in the barrel?
@DoubleSun
Link Posted: 8/21/2020 4:05:42 PM EDT
Thats firing way out of battery......like you have a small ring from a split case left in your chamber.....

Link Posted: 10/4/2020 4:38:54 PM EDT
What gun is it?
Link Posted: 10/24/2020 11:31:36 AM EDT
Remanufactured ammo has never had a stellar reputation. I'm not saying it can't be fine, you are dealing with a company that processes millions of "used" brass cases without any knowledge of each case's history. If anything is stuck to the interior of the case (mud, spider nest, etc.) you can get over pressure. Oddball military headstamps need different powder charges or chucked. A double or triple charge will blow any gun up.

Virtually all manufacturer's warn against using reloaded ammo, so there's that.
Link Posted: 10/24/2020 11:33:59 AM EDT
I had a .45acp round get stuck in the barrel of a Sig P220 in the mid 80's shooting a local gun shop's reloads. No powder, just the primer drove it in. They lost a customer, not only for their product, but for any other remanufactured ammo vendor.
Link Posted: 11/18/2020 9:16:21 PM EDT
I’m going to venture and say the handgun was based on a subgun with a telescoping bolt.
Link Posted: 2/25/2021 9:34:14 PM EDT
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By Villafuego:
Thats firing way out of battery......like you have a small ring from a split case left in your chamber.....

View Quote



THIS.
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