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AR-15 kaboom (link provided)

Discussion in 'Handloading and Reloading' started by Timmypage16, Mar 26, 2012.

  1. Timmypage16

    Timmypage16 Active Member

    The link below has an interesting discussion talking about a kaboom in an AR-15. I would enjoy some of your guy's opinion on it. This is not my post, but I stumbled upon it reading on the ar15 forums.

    I think that it was caused by an obstruction of the barrel. Based on the description provided, one of the failure to fires could have been a squid load causing the barrel to be obstructed resulting in the next round to cause the kaboom. This is the only reason why I think that they were able to recover a bullet from the barrel.What do you think?


  2. Otto

    Otto Well-Known Member

    There's no bulge in the barrel so I'd rule out obstruction.
    Most rifle powders fill .233 cases up to the top of the neck so I doubt it's an over charge.
    My guess would be out-of-battery discharge.
    This is why I don't shoot other peoples reloads and I bet this guy won't either from now on.
  3. animator

    animator Well-Known Member

    Out-of-battery fire, which would be difficult to accomplish in an AR.. or case failure at the web.
  4. blarby

    blarby Well-Known Member

    OOB wouldn't necessarily cause a case head detonation. You would probably have a discharged cartridge. ( the bullet would be out of the brass )

    This is probably case failure.

    However, the bullet copper transfer onto the feed indicates there may have been ignition and shock with the round ON the feed, not in chamber, and in a weird angle, I might add.

    Unless he loaded it with pistol powder ( which I doubt, as they fired 494 of them previously) it would be hard to charge a case to this level with rifle powder.

    Check your brass.................... this is one of the many reasons.

    It is however possible that it slammed/fed sideways, struck the primer, and ignited OOB... releasing the pressure with the bullet pinned against the frame/slide rail, and venting through the weak point in the brass.

    Thats a toughy...maybe someone better versed in the platform can help.
    Last edited: Mar 27, 2012
  5. animator

    animator Well-Known Member

    Looking at it a bit closer, you can see where the head flowed into the ejector opening on the bolt face, so it was definitely some high pressure involved.

    Another speculation would be the case failed to fully feed, and the bullet got jammed further back in the case prior to fully chambering, creating the catastrophic increase in chamber pressure when the round fired.
  6. evan price

    evan price Well-Known Member

    1. Contaminated powder (mixed powders- fast pistol powder got left in the powder measure) maybe.
    2. Weak neck tension on the brass, the round nosed into the feed ramp and the bullet slid nearly all the way into the case when it chambered, making a very compressed load.

    The side of the bullet looks like it was deeper in the case than just to the cannelure-
    However, what's caused that ring about 2/3 of the way down the nose of the bullet?
  7. Timmypage16

    Timmypage16 Active Member

    I believe that ring on the bullet was from the rod they used to pound it out of the barrel.
  8. MtnCreek

    MtnCreek Well-Known Member

    Just a thought on the bullet pushed back: I used to shoot commercial reloads from a local source. A friend and I went in together on a couple thousand .223/55gr FMJ’s. Both of us had many bullets pushed back into the case to the point where powder could escape between the bullet and case neck. I had unloaded my chambered carbine several times to find a cartridge like this in the chamber. I have little doubt that both of us most likely fired a cartridge (or several) with the bullet pushed in. I’m not saying that it could not or would not cause a major overpressure, just saying that I <Think> I’ve shot a cartridge in that condition w/o a KaBoom.
  9. steve4102

    steve4102 Well-Known Member

    The offending bullet was still in the barrel!
    Classic sign of a barrel obstruction.
  10. 243winxb

    243winxb Well-Known Member


    Obstruction like Steve said. [​IMG][/URL][/IMG]
    Last edited: Mar 28, 2012
  11. jerkface11

    jerkface11 Well-Known Member

    Several rounds that did not go off followed by one that went off out of battery. That says one thing to me HIGH PRIMERS.
  12. Superdave70_02

    Superdave70_02 Active Member

    Maybe he loaded a soft pistol primer loaded high that got set off by the bolt face?

    I was also wandering about maybe not cleaning out the powder hopper good and getting some fast pistol powder on the first couple rounds.
  13. snuffy

    snuffy Well-Known Member

    Impossible! The brass showed a normal firing pin dent in the primer. The AR-15 platform will not allow the firing pin to protrude far enough to make that normal looking firing pin dimple WITHOUT the bolt being completely rotated into battery.

    Most .223 powders run at nearly 100% load density. That means there's no room for the bullet to be pushed back to account for increased pressure for a deep seated bullet. Besides, deep seated bullets in rifles is NOT the same as straight walled pistol/handgun ammo.

    My guess is one of the no-fire previous rounds spit it's bullet out of the case under primer power. It's possible 2 bullets were stuck in the barrel. The next round, the one that blew, tried to push the obstruction out. What most fail to realize is; there's air trapped between a bore obstruction and the oncoming bullet fired by the next round. The trapped air has to raise in pressure enough to move the bullet/obstruction. This usually causes a barrel bulge, or sometimes a burst barrel.

    In this case, the case head blew before the second bullet could exit the barrel, relieving the pressure, allowing the bullet to stop.

    I think a bore scope examination of that barrel would show where a bullet stopped ahead of where the recovered bullet stopped. It might also show a bulge that can't be felt on the outside.

    We may never know for sure. But one thing I do know, blaming reloads is NOT the right answer. Taking care while reloading any ammo will result in good ammo and safe shooting. Yes, there's some that should NOT ever consider reloading, perhaps that's what happened here, somebody with the mindset of get it done, don't bother me with details.
  14. sugarmaker

    sugarmaker Well-Known Member

    Sure looks like an obstruction to me - extreme copper fouling after 500 rounds? With those kinds of pressure signs on the case the bullet should exit if the bore were clear. Max charge of temp sensitive powder sitting in a hot barrel for too long?
    Last edited: Mar 27, 2012
  15. Clark

    Clark Well-Known Member

    I have blown up lots of guns in experiments and have lots of overloaded cases from ARs that never hurt the AR.
    I was going to post that there does not seem to be much pressure, just a failed case where there should have been case support by the chamber.
    The resultant gas cutting makes are real mess of some secondary failures.

    Glad to see someone else figure it out.
    I was starting to worry about the internet.
  16. popper

    popper Well-Known Member

    OOB is easy to get in AR. Firing pin floats and sometimes sticks. I suspect inspection error and case failure.
  17. MEHavey

    MEHavey Well-Known Member

    That I have not seen before in an AR.
    Any citations/causes/occurances that readers know of?
  18. ClickClickD'oh

    ClickClickD'oh Well-Known Member

    AK and SKS yes, AR? Unless you have some sort of telescoping firing pin in your AR... not so much.
  19. joustin

    joustin Well-Known Member

    Would need a magic or really long firing pin for it to protrude beyond the bolt face before it cam's and locks in the chamber.

    Sent from my Kindle Fire using Tapatalk
  20. steve4102

    steve4102 Well-Known Member

    Even with a failed case the bullet would have exited the barrel, which it did not.

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