AR-15 failure

[66gt350]

AR-15 failure -- edited

Ok...it was a little more than a simple failure...it went boom.

I took my AR-15 out shooting for the third time recently and had a catastrophic (to say the least). A buddy and I were almost done for the day. There was about 25 rounds left and when that was gone we were done. My buddy loaded another clip and fired the first shot and said "Houston we have a problem" When I looked this is what I saw:

Holy crap...it's dead. On the way home he mentioned that the last round of the previous clip failed to eject...cause when he went to load the first round the spent casing went flying.

Talking with all of the gun shops, I think that I've narrowed it down to a few possibilities and one that I've ruled out of what went wrong and I want your opinions. The upper is (was) a Bushmaster. The ammo was stuff that I reloaded, with mixed military brass and 24.0 gr. of AA2230 powder and CCI small rifle primers.

1. There was a problem with the bolt.
2. I used a progressive press and in the powder measurer, maybe I didn't do a good enough job of cleaning it out and the powder got contaminated with some pistol powder. I thought that I got it all out. How much pistol powder would do this?
3. I did run out of powder...I caught the last shell with ~14 grains of powder...when I came close to running out, I was measuring each charge...I could have missed one.
4. double charge...very unlikely. I just tested and only 30 grains of powder fills the case. 14 gr of powder would have made a heck of a mess!!
5. The last round of the previous clip was a squib and the guy shooting didn't notice and the bullet was still in the barrel when he fired off the next round...boom

I'm leaning towards #5, maybe #1 (very slightly)...

whatcha y'all think?

 

[Duke of Lawnchair]

Sounds like #5, but more importantly, sounds like you and your buddy went home safe & sound.

-Jim

 

[Darkside]

Man that bites. Hope nobody was hurt.

Ditto on #5

Should have checked the bore after the squib load.

Darkside

 

[66gt350]

Ya...if it was me...I would have heard the squib load and realized there was a problem, especially when the previous round didn't eject. And I would have checked things out. I guess I won't be letting anyone, except maybe my g/f shoot any of my guns!!

Luckily, no one was hurt. The ejection port cover is out there somewhere, and I think that came back and hit him on the lip.

thanks guys
Rob

 

[Darkside]

You might look down the bore. Look to see if there is a ring or swelling of the bore where the bullet was stick. If so you found the problem.

Darkside

 

[Darkside]

BTY, Looks like your top half of the rifle is a gonner. Make sure you inspect the lower VERY, VERY well (maybe even have it professionally inspected) before installing a new upper on it.

Darkside

 

[spacemanspiff]

The ammo was stuff that I reloaded, with mixed military brass and 24.0 gr. of AA2230 powder and CCI small rifle primers.

i'd put a shiny nickel on a squib load, maybe due to a light powder load? not enough to work the action? the primer itself should be enough to at least push the bullet a little ways, right?



glad you're all safe though.
also glad it happened to a bushie instead of a colt. j/k!

 

[bytor94]

Looking at the last picture, I would say your lower is hosed too. I hate to see the early demise of a fine rifle.

Just glad that the two of you went home with all of your original equipment. <you were wearing safety glasses weren't you?>

 

[redneck2]

Look at the bright side...

nobody lost any body parts. The gun can be replaced.

If you've always wanted to build an AR from parts, you'll have something to start with

 

[444]

"I would have heard the squib load and realized there was a problem"

I don't know about that. I have had a number of squib loads. At least twice I didn't notice anything out of the ordinary until the next round fired into a plugged bore.

 

[66gt350]

Shell

I just removed the shell from the chamber. and it is definately messed up.

It lookes like it wasn't completely chambered when it went off. It wasn't a slam fire, 'cause that was one question I asked. It's like my buddy let the bolt close slowly instead of just letting it slam shut.

Like was posted earlier...I was just glad that noone was hurt. It's only a gun and it can be replaced...

rob

 

[GreenFurniture]

Did you check headspace prior to shooting?

 

[66gt350]

I didn't check the headspace...It was a complete upper from bushmaster. Don't they check the headspace before shipping them out?

 

[Jeff White]

I'm with 444 here. You won't always hear a squibb load. I had one (with Federal XM193) at Pat Roger's Carbine course in 2003. My only clue was the next round wouldn't chamber. If the projectile had been stuck far enough down the barrel to allow the next round to chamber, I would have blown up my Colt 6920.

I doubt it was a headspace issue. It most likely was a squibb load. Another thing to watch for on reloaded ammo with an AR is high primers. I had some a friend had loaded and given me and it fired out of battery as the round was being chambered. Blew out the floorplate of the magazine and bent the extractor. No injuries and no damge execpt the ruined extractor and magazine. I disposed of all the rest of the reloaded ammo and have only fired factory ammo since.

Jeff

 

[bogie]

My professional opinion is that you had a stuck bullet.

Says something about the rifle's design in that you still have all your fingers, eyes, etc...

That was also a fairly "mild" 2230 load, right?

 

[TexasRifleman]

The ammo was stuff that I reloaded

Glad no one got hurt. This is why I packed up my reloading gear a few years ago. Now think of all the money saved on ammo by reloading. Did you save enough to cover the cost of a new rifle? I blew up a Delta Elite years ago and that was the end of my reloading. One squib and you're toast, and no they are not always easy to detect, especially when you're shooting fast.

 

[Bartholomew Roberts]

What does the barrel look like? That should answer the question of whether it was a squib load or not. If it was a squib, it could not have gotten too far down the barrel in order to inflict that kind of damage on the upper.

Did the kaboom happen after your buddy pulled the trigger or as he was chambering the round? It seems pretty clear from the casing that the round had not fully chambered when it went off. Normally an AR15 firing pin cannot hit the primer unless the bolt is in battery and has turned back into the carrier.

This tends to make me suspect that the round may have had a high primer. Just a complete WAG on my part; but could the hammer have driven the firing pin into the tail of the bolt and the firing pin have transmitted enough of that force to the bolt to detonate a primer?

 

[beerslurpy]

Is reloading 5.56 really that much cheaper/accurate than the GI factory stuff?

 

[Coltdriver]

It is always surprising to see how much damage occurs when a ka boom happens. Good to hear nobody got hurt.

From what you describe I would say squib too. Huge red flag to not have a round eject with your AR. I have one and don't recall ever having a round not eject.

Let us know if the barrel bulged or if you discover another reason for the problem.

 

[66gt350]

I've looked down the barrel...granted I'm no gunsmith and have an untrained eye...but I did not see any bulging or any rings. The rifling looked good. This was the heavy target barrel from Bushmaster, would that keep it from bulging? So, I think that the barrel is still good. But I'm still shipping it back to Bushmaster for them to check out and install a new A2 upper.

It was not a slam fire, I was told (at least this is what he says...I was over shooting my XD40), is that he went to chamber the first round of the clip and when he pulled the handle the old one came out and closed. He pulled the trigger and then it went boom.

[bowing head in shame] This wasn't a bushymaster lower...but one of those nuetered People's Republic of California legal lowers ...and the this version the bolt doesn't lock open after the last round. the newer ones do.

 

[Darkside]

Just a little speculation here.

1. Your buddy is banging away..bang...bang...bang...click or maybe a slight pop.(primer from squib load inserts bullet slightly in bore)
2. Buddy thinks...mag must be empty.
3. Buddy drops mag inserts new loaded mag.(did you check for loaded rounds remaining in the mag he dropped?, just courious)
4. Buddy hits bolt release and nothing...(scratching head) he works charging handle and sees the empty case eject. At the same time the fresh round drives the squib bullet just far enough into the bore for the bolt to close and lock.
5. KABOOM

6. After counting all of his fingers he says Holly $#!. (you now the rest).


Just a guess.

Darkside

 

[66gt350]

Darkside,

Being a California lower...there are no clips, just the internal 10 round mag. And with this version of the lower, there was no bolt catch. So on after the final round the bolt closes and if you don't count the rounds as you shoot, you dry fire.

So, instead of dropping the mag, he breaks it in half and loads the clip not realizing it was a squib. Pulls the charging handle to load a new one the old one comes out...and the rest is history. But would there be barrel damage where the first bullet stopped?

I guess that I may never know exactly what happened...but it would be nice to get a piece of mind, so that it won't happen again.

thanks all
Rob

PS Does anyone want to buy a slightly used complete Bushmaster Upper? only 300 round through it!!!

 

[Darkside]

My appolgies, I should have read the post a little closer on the CA lower. I forget about those break open things.

If the squib bullet just started to enter the throat and the incoming round pushed it in a little further, at the same time, the new/live round bullet may have been pushed back into the case. If this did happen, the presure ring/swelling may be at the forward end of the chamber and very hard to detect without doing a chamber cast and taking some measurments.

I had this happen on a 1911. I was very lucky. The only thing that made me take notice was my accuracy went to pot all of a sudden. I disassembled the pistol and eyeballed the bore and chamber, Looked fine. During reassembly I accidentally slipped the barrel bushing on the barrel backwards . The bushing slid down the barrel and stopped 1/2" before the locking lugs. This showed the bulge in the barrel. I went home and made a chamber cast including about 1" of barrel. Took some measurments, and the front of the chamber/bore were .020" oversize.

Try making a chamber cast, include an inch or so of the bore. Take some measurments and see what you come up with.

Let me know

Another question, Do you use a heavy crimp on your reloads for this rifle? If you dont, it might be possible that the live round bullet was pushed back compleatly into the case, if there was enough space inside the case. Just a thought.

This sort of thing would drive me nuts, until I figured it out.

Darkside

PS. I will give you $20 bucks for the upper.