PCC Semi-Kaboom

[DDTSGM]

Don't know where to put this, if mods think it needs to be elsewhere fine with me.

My wife was practicing for a PCC match this coming Sunday when she had a blown case just about as good as I've ever seen. She said 'Ow, that stung my face.' This piqued my interest so I took a look down the bore - clogged. This upset me to no end, I thought I'd loaded a squib round. I had her strip the mags she had just loaded up and put them in the blue box we had just loaded them out of. She'd had about 5 runs over the stage I'd set up. and practice was done for the day.

While I was tearing down the stage she was policing brass and found a case that she called me over to look at (shown here with the remnants of the blown case):



It appeared to me that the case must have fired half out of the chamber and that the case walls had held, once we got home this indeed proved to be the case:



What I figure happened is the bulged case fired out of battery and didn't have enough oompf to clear the bore. Next round gets chambered and fired, pressure spike pushes first round out of bore and causes case to rupture leaving squib in barrel.

Is this plausible?

At home, I manually de-primed the case and primed the case, stuck it in the chamber (to the bulge, of course) let the bolt go forward and pulled the trigger. I'd already done this before priming the case, so I knew the hammer would fall, what I didn't know is whether the primer would pop. It did.

The FCG is functioning as should be, it is a single stage with a pretty crisp light break with minimal reset. It is a GI type, not a cassette. I'm going to put an MBT 2 in it for her.

The loads we mine, loaded on a RL550, each round I load gets case-gauged using a Shockbottle 'Hundo.' At the time of this mishap the PCC had probably had 400 rounds through it since cleaning.

Not going to provide details on components until I've reached out to them Monday.

ETA: The suib was about 3-4 inches into the 16inch barrel, so I went at it from the muzzle:

[OlongJohnson]

Is this "Ruger PCC" or generic, unspecified PCC?

[DDTSGM]

Is this "Ruger PCC" or generic, unspecified PCC?

AR style, glock mags.

[TGS]

AR style, glock mags.

More specificity is needed. I'm not up on all the AR-style PCCs, but if using an actual Colt or Colt derivative system it should be physically impossible to fire OOB with the exception of the firing pin being stuck in the forward position due to either a parts breakage or excessive fouling.....something I mentioned in a recent thread on AR drop safety. Otherwise, the cut out in the rear of the bolt should not physically allow the hammer to hit the firing pin until the breech is closed.

So, I'd check the condition of the firing pin and spring before firing the gun again.

[blues]

Glad the missus is okay, Dan.

[AJLooch]

Are you running a extremely light buffer or buffer spring in the gun? Even a normal AR-15 buffer is too light for a blowback AR 9.

[TGS]

More specificity is needed. I'm not up on all the AR-style PCCs, but if using an actual Colt or Colt derivative system...

Reading more this morning, and there seems to be a plethora of PSA AR9s firing out-of-battery to the point that it seems like an intentional design feature.

I'm not sure what the difference is causing it, but I never heard of a single OOB when we still used the Colt M635 at my agency. They suffered parts breakages, but they weren't patently unsafe to use.

Anyways, I guess that's only applicable if you're using the PSA kaboom9.

[DDTSGM]

Are you running a extremely light buffer or buffer spring in the gun? Even a normal AR-15 buffer is too light for a blowback AR 9.

7.2 ounce buffer, standard carbine lenth spring.

[DDTSGM]

Reading more this morning, and there seems to be a plethora of PSA AR9s firing out-of-battery to the point that it seems like an intentional design feature.

I'm not sure what the difference is causing it, but I never heard of a single OOB when we still used the Colt M635 at my agency. They suffered parts breakages, but they weren't patently unsafe to use.

Anyways, I guess that's only applicable if you're using the PSA kaboom9.

I'm pretty sure this is not limited to the PSA 9mm bolts as the bolt in my wife's PCC is not a PSA. I just primed the case and stuck it into my PCC (which has a different brand bolt than my wife's) and it also fired the primer in the bulged case.

[TGS]

I'm pretty sure this is not limited to the PSA 9mm bolts as the bolt in my wife's PCC is not a PSA. I just primed the case and stuck it into my PCC (which has a different brand bolt than my wife's) and it also fired the primer in the bulged case.

This is all good info, but is there a reason you're being so secretive on brands and platforms?

@5pins, can you try this with your Colt 635? I'm just curious. I was told by our FTU years back that the bolt needed to be within a mm or two of closed in order for the hammer to strike the FP. I'm wondering how true that is, especially since we're playing GS-14 classified with platforms here.