Well,...that sucks - blown 9mm case in AR

[Suck My Glock]

Went out to Table Mesa Rd. today to tune up some of the machines and get my gunpowder fix. Shortly after beginning, 2nd round of 147 grn FMJ reloads blew the base and tried to explosive-weld itself to the boltface, leaving the case wall stuck in the chamber.

Lovely.

Was running a suppressor at the time, so didn't have ear protection on,...SO IT WAS LOUD!!!! Ung.

I've had case separations before in open-bolt guns like Stens and Uzis, but never had one in a closed-bolt system before. At least I didn't get brass splinters embedded in me anywhere, so that was cool. But that pretty much wrapped up the session for the day, and now we get to hunt for our special 9mm stuck case wall threaded bolt I use for pulling such crap out of chambers. I had to use pliers to get the case head off the bolt.

[DuneShoot]

You're right, that does suck!
Can it be taken off and bolt reused?

[Suck My Glock]

You're right, that does suck!
Can it be taken off and bolt reused?

Yes, I think it will be fine. I'm just wondering if the loading was to fault or was the case just too weak from previous use. I suspect it was a piece of brass that had been loaded too many times or too hot and just escaped my sorting out such specimens before I loaded up some ammo that should have been nowhere near maximum.

[Jack Dupp]

Out of battery detonation. Heavier buffer and spring to prevent bolt bounce. Something like an 8+oz buffer. It happened to me 3 times before I wised up.

[Suck My Glock]

Out of battery detonation. Heavier buffer and spring to prevent bolt bounce. Something like an 8+oz buffer. It happened to me 3 times before I wised up.

You might be right.

[NBC_LT]

Thankful you are okay, and that your carbine is salvageable. Maybe buy a lotto ticket with the hands and eyes you still have?

Not a bad idea to quit semi-auto 9mm cases past 2 reloads - that became my limit after an uneventful case separation in my open bolt Sterling SMG.

[xerts1191]

Good you escaped any injury

[HPMike800]

Just My 0.02 but 147gr bullets are awfully heavy. It is easy to get a compressed load with those. Heavy bullets, fast pistol powders and compressed loads can increase pressures dramatically.
The reason for so many 180gr 40S&W blow ups.
Mike

[338lapua]

I had this issue a couple years ago with about 100 out of battery detonations. Two different bolts, multiple spring changes as well as buffers. I know the ammo was fine. Same ammo in a MP-5 not a single issue. Winchester, CCI and Remington ammo same problem, Replaced lower parts kit, upper receiver and barrel, still same issue. Replaced lower with a lower that takes H&K mags, firing pin spring and firing pin and it stopped. I threw the gun in the safe. Bought another Colt 9mm carbine and shot the rest of that batch and no more problems, 6K through the Colt without issue. Never had a single issue with a Colt 9mm carbine.

So in the 4 months trying to fix it I did find one time where the firing pin was protruding, cleaned bolt same problem within a few rounds. Primed case in chamber fired when bolt slammed home a few times. I flew back east with the rifle and bolt I bought from one company and they put a different bolt and same problem. Put the upper on a lower that used colt mags and a colt buffer and spring and it stopped. Put my colt bolt in the offending upper with the colt lower and a thousand trouble free rounds.

Does it takes glock mags?

[Suck My Glock]

That sounds like some weird juju going on with yours, 338lapua.

Nope, been using EndoMag conversions of Magpuls. I like the long feed chute internal to these, since they allow for feeding of any and all bullet profiles, including SWC.

[338lapua]

So this is one that is a Blazer round. Blazers are pretty clean after firing. So this one fired and the next round fired out of battery and the plated bullet lodged in the previously fired case. You can see half a case in chamber with bullet.

this is the round that went out of battery and lodged the bullet in the previously fired case.

[338lapua]

This is the case after removing it. It blew the Glock magazine out of the mag well and blew it apart. This is shot through the mag well. These pcc rifles can have issues at times.