Out of Battery? What is it?

[Stock]

Ok-need some help on the learning curve-an "incident" happened-heres what I saw-a part(3/4 )of the casing, was stuck in the barrel (9mm semi-auto carbine), the bottom/rim area was gone and the bullet was about half way down in the barrel. I was told (by a Gunsmith) that there was a "squib" and that the gun had gone "out of battery". The round was a well known brand of defensive ammo. I would appreciate any (plain language) explanation of what may have happened-I have no further info. What malfunctioned-why? Thanks for the assistance.

 

[badkarmamib]

Sounds like it fired out-of-battery (bolt not completely closed), and, since the pressure wasn't completely contained in the chamber (because the bolt wasn't completely closed), the case ruptured, with only part of the pressure pushing the bullet(i.e. not enough to clear the barrel), and the rest of the pressure blowing the unrestrained rear of the case off. This would be indicative of a firearm malfunction, not an issue with the ammo. Firearms are (usually) designed with disconnectors to keep them from firing while out-of-battery, for this reason, but it is a mechanical device, and as such can fail. Hope this helped.

 

[joem1945]

It sounds like part of the case was stuck in the chamber and the case failed either due to bad brass or the bolt was a little out of battery. When the case failed there wasn't enough pressure to move the bullet out of the barrel. Could be any or all of the following, bad brass, overcharge (doubtful), dirty chamber area. You may never really know what caused this problem.

 

[yugorpk]

What kind of gun is it?

 

[Stock]

Thank you both for the info-that clears up a lot-so if Im reading it right, the ammo failure was apparently due to the gun (out of battery) failure-not the other way around-and the "out of battery" appears to be then a mechanical "timing" issue? (where for some reason) The parts don't work in sync. Thank you again- Please feel free to even give "good guesses" on any further details or possible causes of "out of battery" situations

 

[Stock]

Thanks for the responses-It would seem then that the gun caused the ammo failure and not the other way around. Any further info or even good-guesses as to how/why the "out of battery" (mechanical function/timing issue) would have occurred would be appreciated.
It was a new build by a Gunsmith-using a QC10 lower-(I don't know if it had been "test fired" or to what extent-in any way-Thanks Again-
I do not know what parts went into it-and don't have it in my possession any longer. (9mm Carbine)

 

[243winxb]

Many times, the reason is unknow. http://s338.photobucket.com/user/joe1944usa/slideshow/Firearms%20%20and%20%20Reloading/KABOOM Most times ammo is reloaded, but does happen with factory rounds.

 

[MErl]

The gun is not entirely without fault. The should be some mechanism such that the firing pin cannot be struck until the bolt is fully closed.
The easiest way I can see such an event happening is the previous round had a head separation and the front half of the brass case was still in the chamber. The next round hit that and hung up, stopping before fully chambering. It was then set off by the gun and boom. There are many other ways it could happen though.

 

[wally]

Generally, count your self very lucky that your and/or the gun weren't damaged. At the very least, with other than .22lr, usually the magazine ends up blown out of the gun and damaged.

I agree with MErl, something is wrong with the gun, a lot of effort goes into gun design to prevent out of battery firing. Could have been a partial bore obstruction, look for a "ring" or bulge in the barrel.

Having this happen with handgun rounds is a lot less serious than having it happen with center-fire rifle rounds, but its nothing to take lightly in any event because there is danger to bystanders from fragments flying out the ejection port -- why everyone needs to wear eyepro at all times when on the firing line.

 

[Stock]

Thankyou

Thanks to all who replied. One of the comments about me being lucky-was absolutely right-I kind of thought that when the big orange blast came out of the chamber that something might have went really wrong-the magazine did blow out-that may be why thankfully I didn't get another shot off. When I saw later at the gunshop that the casing was stuck in the barrel and the back was blown off-with the bullet still in the barrel I was a little shaken up-I guess I'll never know why it happened-only now I know that it can-Good News though the guy was upstanding enough to buy it back no questions-full refund.
Thanks again for all the info-

 

[Teachu2]

Always a good idea to refund (collect the evidence) when something goes wrong on a new gun. Fortunately, no injury to deal with.

 

[gwpercle]

The term "squib" usually refers to a round with little or no powder loaded. When fired there is not enough powder/power to get the bullet clear of the barrel and it sticks in the bore. But this does not appear to be what happened, it would not blow the rim area out....a fully loaded round would do this. The action wasn't fully closed and or locked. Usually there is some sort of disconnect to keep a round from firing from an unlocked action, but an inexpensive 9 mm carbine could be lacking this detail just to cut cost. A simple blow back action might not have this feature.
I would say gun not ammo problem.
Glad you weren't hurt and he did a refund...I see why he threw in that squib excuse , he was the gun builder and could have had a lawsuit on his hands.
Gary

 

[mag1911]

The chamber might have been dirty enough to "stop" the round from chambering fully. If the bolt slammed into the back of the cartridge while it wasn't fully seated the impact could possibly set off the primer.

And/or if the bolt was dirty enough the firing pin might not have fully retracted. If the firing pin was sticking out slightly when it slammed into the cartridge it might have set off the primer.

Glad no one was hurt.

 

[Tirod]

There is another cause - bolt bounce. A light bolt and carrier assembly can rebound when slammed against the chamber - which causes it to unlock. If the primer was struck as it locked up and the bolt then starts unlocking as the pressure builds it could be partially extracted at the peak moment the round gets pushed down the bore.

"9mm" carbine definitely includes AR uppers which are known to exhibit the issue when timing is premature and buffer/bolt assembly less than optimal. High cyclic rate firing is one symptom and why Crane specifies a heavier bolt assembly for the MK18 SBR to slow it down. A gun like the AR15 cannot be fired out of battery but it can come out of battery due to bolt bounce. http://www.bing.com/videos/search?q...DACCB1EAA2A8D1C1A9FCDACCB&fsscr=0&FORM=VDMCNL

 

[dogmush]

Since you called it a new build on a Quarter Circle 10 Lower, can we assume this is a 9mm AR variant?

This is what we know: The bullet is still in the barrel, and the bolt came back while there was still excessive pressure in the chamber, causing case failure. (Separated case, big fireball, mag destruction are all signs of this)

It's worth remembering that a 9mm AR is a blowback weapon so the bolt doesn't lock, and the normal safety of an AR's firing pin being too short to poke through an unlocked bolt doesn't apply here.

So a couple things could have happened:
The round before it blew up could have been the squib your gunsmith mentioned. The obstructed bore would have raised chamber pressure, opened the bolt and blown out the case on the next round. If there are two projectiles in the bore when you hammer them out, this is the likely cause.

The round could have been overcharged. Again, high chamber pressure would have opened the bolt early, rupturing the case and leaving the projectile stuck in the bore.

The gun's spring, buffer and bolt could be set up improperly. Since nothing locks the bolt in battery, if the recoil system is to light there's not enough inertia to hold the bolt closed until the bullet leaves and pressures drop. Again, bolt retracts early, case fails, pressure vents and the bullet is left stuck in the barrel.

As Tirod mentioned the bolt could have bounced right as you pulled the trigger. This would have required extremely [un]lucky timing on pulling the trigger. Were you shooting fast?

Something could have set the primer off early. Depending on the hammer design, it might be possible (but unlikely, I'd have to check, and my 9mm AR isn't handy right now) for a hammer that missed the disconnector to follow the bolt home and press on the firing pin before the bolt is all the way closed. This theory is kinda flimsy, and IMHO unlikely, but I guess it's possible.

A dirty chamber could have held the new round far enough out of the chamber that the case had no support, but far enough in that the hammer could still hit the firing pin. (Again, that's probably a pretty narrow window given the geometry of the hammer and back of the bolt.) Primer ignites, case fails, pressure vents, yada, yada.

There's probably some other things that could cause it as well. I think it's pretty unlikely that the round went off early, as that bolt/hammer geometry is pretty easy to control, and would be designed out of the gun (I hope. There are a number of AR hammers out there, and we don't know which you have.)

It's more likely, in my opinion, that the bolt opened early, while chamber pressure was too high, and the case ruptured from there. There's nothing holding it closed except inertia from the bolt and buffer. So either a bore restriction/obstruction from the previous round, or the ammo was too hot for the installed bolt/buffer/spring. Check those first.

 

[Stock]

Thanks for the input. A huge amount of possible causes. I don't have the gun (was able to return it) for any further examination (bolts/springs/etc). But I would say that in the future I'll be a lot more careful about my knowledge of the quality of the product and parts than I was in this situation. Thanks again.