My AR blew up on me today...

[gmar]

Yeah, I shot that ammo a lot before today and I don't think I used my forward assist but I'm not 100% sure.

 

[Boehlertaught]

I'm just finishing "Hatchers Notebook" and many of the pictures he notes of blown up rifles look similar to yours. Yes, his pics are of bolt action rifles but the damage looks similar. The pressure a properly manufactured barrel can take is tremendous...test loads on barrels may be over 150% of a normal charge. Bullet setback certainly increases a rounds pressure and it could go as high as a test round. IMO one setback round would not blow up a good quality barrel but a steady does of them would pound the hell out of a barrel and it could fail prematurely. The two issues that most often caused damage noted in Hatchers book were out of battery discharge and barrel obstruction. The out of battery discharge tended to do more damage to the receiver than your damage shows. As mentioned earlier, damage due to a barrel obstruction will show a swelling in the barrel. The split breech end of your barrel is similar to the pictures in Hatchers book of barrels that had a flaw in the metal that made the barrels weak. Just some thoughts.

 

[uncle money bags]

It was an obvious over pressure. Just use the process of elimination to figure it out.

1) If the barrel is not split, cracked or bulged it wasn't an obstructed bore.

2) Since you cant double charge a .223 case with appropriate powders that wasn't it. That doesn't mean that the wrong powder wasn't used though. I saw pics of a billet upper that grenaded just like that due to HS6 powder getting mixed with his BLC2. (they look similar)

3) If it's not an obstruction, or powder snafu that pretty much leaves you with bullet setback or OOB. Did the round chamber normally? Did you use the FA to chamber it? Have you shot any of that batch of ammo before? I'm still thinking bullet setback upon chambering that round.

This is the correct answer. However, I would add that the chances of an out of battery discharge in an AR 15 is right about zero. It is physically impossible for the firing pin to protrude beyond the face of the bolt until the cam is activated to the point of lock up.

My bet; without pics of the barrel or obvious barrel failure, is an over charged round. There seems to be a growing trend in the last 18 months or so of this type of cato caused from misloaded ammo. Just to clarify, an obvious barrel failure does not include the barrel extension. I would not be surprised if it is cracked, most probably at the 12 o'clock position longitudinally with the index pin.

Im glad you werent hurt dude, that could have been alot more serious and it looks like someone was looking out for you.

 

[gmar]

I'm just finishing "Hatchers Notebook" and many of the pictures he notes of blown up rifles look similar to yours. Yes, his pics are of bolt action rifles but the damage looks similar. The pressure a properly manufactured barrel can take is tremendous...test loads on barrels may be over 150% of a normal charge. Bullet setback certainly increases a rounds pressure and it could go as high as a test round. IMO one setback round would not blow up a good quality barrel but a steady does of them would pound the hell out of a barrel and it could fail prematurely. The two issues that most often caused damage noted in Hatchers book were out of battery discharge and barrel obstruction. The out of battery discharge tended to do more damage to the receiver than your damage shows. As mentioned earlier, damage due to a barrel obstruction will show a swelling in the barrel. The split breech end of your barrel is similar to the pictures in Hatchers book of barrels that had a flaw in the metal that made the barrels weak. Just some thoughts.

Thanks...that's good info. I took everything apart when I got home and other then the stuck piece of brass, I don't see anything wrong with the barrel. What should I be looking for and what can I do to test it to make sure it's good to go?

 

[uncle money bags]

If it were me, that entire upper is toast and get hung on the wall next to the piece of engine block from my first race engine that exploded right after turn two at Hallett.

If you are an adventurous sort, remove the barrel and inspect for obvious damage to the barrel extension as well as the barrel and slap that puppy on another upper. I DO NOT recommend this course of action. The damage may very well not be detectible by inspection with your eyes, even under magnification. It is far better to chalk this up as a learning experience than to tempt fate.

 

[dennishoddy]

The barrel can be magnafluxed for invisible cracks. Otherwise its a tent stake.

 

[gmar]

The barrel can be magnafluxed for invisible cracks. Otherwise its a tent stake.

Can this be done locally and do you have an idea of the cost?

 

[castleeleven]

Is this your new SBR? not a reload round right? Sorry to see that happen. But it is important to find out reason..

 

[gmar]

Is this your new SBR? not a reload round right? Sorry to see that happen. But it is important to find out reason..

No, it was my 14.5" BCM with a factory load.

I just emailed BCM to see if they can inspect it for any damage. Hopefully they can do something.

 

[dennishoddy]

Can this be done locally and do you have an idea of the cost?

there are company's in OKC that do this. Google Magnaflux services in OKC, and you will get hits to call.