9mm case blown apart,Why?

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  • RFD

    Active Member
    Nov 22, 2012
    122
    Baltimore
    Can anyone say by looking as to why this 9mm case blew apart? FC marked on rim and a fmj bullet. It is from a PCC . Was it poss. out of battery when it went off? Thanks
     

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    Pale Ryder

    Ultimate Member
    Jan 12, 2009
    6,234
    Millersville
    Which PCC? Was there any damage to the firearm?

    To my non expert eye it does look like an out of battery rupture. Mainly because of the size of the case near the separation, where it looks like it was not supported by the chamber.
     

    Gcs7th

    Ultimate Member
    Jan 26, 2012
    1,280
    AGC
    Looks like an OOB discharge the next question is why did it happen? Hows the primer look or was it blown out? Was the bore was clear after this round or did you get a stuck round?
     

    ken792

    Ultimate Member
    Sep 2, 2011
    4,480
    Fairfax, VA
    I'm leaning towards out of battery firing. There looks to be a bulge ahead of the rupture, so that part was unsupported.
     

    Melnic

    Ultimate Member
    MDS Supporter
    Dec 27, 2012
    15,282
    HoCo
    How fast were you firing? I"m wondering if it has some bolt bounce and if you were fast on the trigger, even if you were not firing fast, depending on the gun, it could bounce back out of battery before you pulled the trigger.
    Also, depending on the bolt design, Each gun has a tolerance for how "closed" the bolt has to be before the trigger can be pulled or firing pin will release. Some have looser tolerances than others. I've had one OOB incident with an inexpensive 22 Semi Auto. Understanding the gun design can tell what the possibilities are.
     

    atblis

    Ultimate Member
    May 23, 2010
    2,011
    I am pretty sure that headstamp is an old Federal headstamp and that does not look like a new case to me. I would not rule out a catastrophic case failure due to faulty brass rather than an OOB event. I've found old Federal brass to be what I'd call brittle.
     

    SCARCQB

    Get Opp my rawn, Plick!
    Jun 25, 2008
    13,614
    Undisclosed location
    I had a similar event with a home assembled AR 9 pistol.

    I made the error of using a standard Weight AR buffer. Since these are direct blowback weapons. I may have had timing issues and an out of battery discharge. I switched to a stainless steel 10 oz pistol buffer( longer and heavier) It’s been reliable since.

    When I had the standard buffer in. ( 3.6 oz) the fired cases were extremely bulged at the base.
     

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