A young friend recently brought me an almost new Rock River AR that had been ruined by a round of commercially reloaded (fairly large company) .223 ammo on firing about the 19th round ever shot from the new gun. The bolt carrier was split, extractor broken and blown off, upper receiver walls bent outward, and the paddle of the bolt stop was sheared off. Nobody was hurt.

I first suspected a squib, followed by a full load behind a stuck bullet, but when the brass from the offending round was driven out of the chamber, I discovered that there is absolutely no evidence of such, confirming what the boy told me about there having been no squib. He's a fairly experienced shooter. No bore ringing or other visible bore defect. In fact, it appears that the barrel is undamaged, as is the lower, except for the broken bolt stop.

The brass of the subject round blew out just in front of the extractor groove for about 1/4 of the circumference, flowed into the ejector hole in the bolt, and has a ring of extruded brass around the remainder of the circumference that is about .005" high. Looks like pressures exceeded 100KPsi, maybe 120K+.

I pulled bullets from rounds out of 5 boxes of the same case of ammo, and the powder charges were in the 23-24.5gr. range. Powder is a fine ball, and looks like maybe AA 2230. Brass is mostly Lake City. A case brimming full holds about 32.4 grains of this powder, so a double charge can't happen, but a 25%+ overcharge could.

Clearly, there was either an excessive charge of the right powder, or the wrong powder was loaded. I'm having difficulty with the idea that a 25-35% overcharge of the correct powder would generate enough pressure to do this, but I'm hoping the brain trust here might chime in. I guess it could reach a "brittleness" threshold with less overcharge than one might think.

OH, come to me, great Brain Trust...

Was it Ultramax? See below what UM did to my gun.







I sent it to them and they repaired it with Bushy stuff. I never could pound the bolt open to see what happened inside, but I know there was no squib and no other problem. Just a KB. The UM rep told me they tought that there had been two bullets loaded in the case. Sounds way weird to me, but that's what they told me. I still have a little mark in my tummy where the magazine blew out and hit me. (Over a year ago!)

Best of luck to your buddy.

Damn, Musicman, I did not expect to see The Answer so soon! Yes, it was Ultramax, and your bolt carrier looks IDENTICAL to the one in my young friend's gun, although your upper received more damage. Two bullets, huh? That just might do it, and I'd not even thought of that possibility. If you'd be so kind, please e-mail me those photos and any others you have handy. And if you've got it handy, it sure would be good to have the lot number off your UM ammo. Was it 55gr. FMJ? Thanks a million!!!

I've just got the pictures on a hosting site, so I'll post the rest of them here, and you can save them from here if you like. I don't have the lot number as I bought 3 of those 150 rd value packs and then loaded up my mags with them and tossed the boxed before the KB happened. It was the 55 gr FMJ. I bought it at Dick's sporting goods in Gallatin, TN around Jan-Feb '07 I think. Tell everyone you know to stay away from that crap. Sure, they fixed my gun and I wasn't seriously hurt THIS TIME, but it could be an eye or worse next time.

I know, everybody says it can happen with any mfgr, even fresh ammo from the big 3, but I haven't seen or heard any first hand experience of a Fed, Win, or Rem round blowing up someone's gun (that is in good, working order, anyways.)



















And here was my baby before that fateful day....

Oh, and I had no damage to my lower.

Thanks for the heads up! I've had enough bad luck with factory ammo lately, and the price is so crazy, that I intend to quit using it for everything, except in my P3AT for self defense and my .22s. I think all the maker's QC is in the toilet. All my centerfire revolvers will use handloads exclusively once my stock of factory ammo is gone.

Flop-shank you may have the best idea.

I've been curious how the AR 15 behaves in a kaboom. Musicmanbass's photos are distressing to see.

Since AA2230 is a ball powder it would seem that it'd dispense well and wouldn't leave a partial charge hung up only to be loaded into the next round. The burning rate of AA 2230 is fast enough that a 25% overcharge would almost certainly wreck things as has been described.

Perhaps a soft case head is the culprit. If the case was dead soft it would be completely incapable of containing the pressures of even a normal load. Years ago there was a big flap about a batch of military ball ammo that was plagued with this problem. It was Frankfort Arsenal '33 dated ammo and was addressed in "Hatcher's Notebook" among other publications as I recall.

I've seen two instances of this happening. Once, on the firing line at a high-power match, an M1A was damaged when a round of military ball ruptured. I don't recall who was the manufacturer of the ammunition. The competitor suffered some minor injuries with some bleeding. The stock was destroyed but I think the rifle was OK. This was a good example to me to wear shooting glasses.

Another time a friend of my was trying out an M1 that his grandmother had just turned over to him. It had been his uncle's but was left at her house after the uncle's decease. Some WWII Frankfort Arsenal ball ammo was included and we went out into his yard to shoot it. A few rounds fired normally and then the gun gave the appearance of coming apart. My face was less than 18 inches from the rifle's left side and I was sprayed with splinters when the left side of the stock blew out. Examination of the case revealed that the primer was missing and a crack ran from the flash hole through the case head and up the side of the case. Was a shame too because this was a super-clean, completely original WW II M1 with a very nicely marked stock. The rifle itself was unharmed and a new stock was procured but the rifle's collector's significance was severely reduced.

Improper annealing in the manufacturing process would cause cases to misbehave in this fashion. Upon firing the cartridge case acts as a seal, an important detail. A lot rides on the strength of the cartridge case. No rifle is strong enough to stand up to the ignition of a powder charge with what amounts to no seal. Those gases will go somewhere beside where they're suppose to go and in such volume as to wreck havoc.

This was an overpressure event, not a brass defect. The brass was loaded by UM from once-fired Lake City. The condition of the firearm was that of one you'd expect to see after a 100KPsi-130KPsi kaboom. No amount of annealing would allow the degree of brass flow evident here with normal .223 operating pressures, nor would the bolt carrier have been split and the frame warped. I've seen .223 cases fail, due to having been reloaded too many times or just being defective, and I've seen it in ARs. Doesn't look like this at all.

UM told Musicman that they'd loaded two bullets in the round that blew his rifle up. How'd they know? Sounds like a problem that had already happened before.

We've learned that the powder is a Hodgdon powder, but based on the charge weights, I'm sure its burn rate is mighty close to AA2230. It is a fine ball that should meter well, you are correct. It also leaves enough room for a significant overcharge. Enough for this much pressure? I still don't know. But with two bullets, HELL yes!

There are quite a few examples of KBs happening with UM, AR15 dot com has had several threads over the last year or 2. The photos you posted are pretty typical of the others I've seen on that site. I can't imagine why anyone would buy the stuff, or why they are still in business at all. I have not yet heard of any serious injuries or worse, nothing short of a miracle really. I suggest to any of you who have UM .223 ammo to just dump it, or bury it, or otherwise be rid of the stuff. Musicmans thread affirms that the people at UM obviously know they are having some serious QC issues, his AR is not the first or last AR that UM is eating the repair bills for.

My wife and I used to call Ultramax "Evil Knievel ammo" because of the packaging. Now I'm seeing a better reason to call it that.

The UM reputation for bad QC and blown rifles is pretty prevalent with the AR community. I would not shoot ANY commercial reloads with the single exception of Black Hills and you can't get their products due to their gov't contracts taking up all their time and resources.

UM is bad juju...avoid it and shoot only factory new ammo in your ARs.

I've heard good things about Georgia Arms, but not regarding AR ammo (in which case I've heard nothing). Has anyone had bad luck with them?

I've just started handloading for the 223 and this is a little disturbing to say the least. If I get a batch of weak brass and can't identify it I'm in trouble. I'll have to do a search to see about how to id it.

One thing I do though is use Varget powder. There is absolutely no way to get a 10% overage in the case with it and I would find it hard to believe you could get a second bullet smashed in there either. I suppose anything can happen.

quote:

Originally posted by bmcgilvray:
I've been curious how the AR 15 behaves in a kaboom. Musicmanbass's photos are distressing to see.

AR-15s do an excellent job of protecting the shooting in case of an overpressure. Notice how there is zero damage anywhere near where the face or firing hand would be.

This same issue in a Model 70 would not have turned out so well.

quote:

Originally posted by smith crazy:
I've just started handloading for the 223 and this is a little disturbing to say the least. If I get a batch of weak brass and can't identify it I'm in trouble. I'll have to do a search to see about how to id it.

Whatever caused that damage could have happened with any other rifle cartridge.