Out Of Battery Detonation AR

[writerman]

OP, this is not out of battery. Impossible. This was over-pressure caused by either an obstruction or ammunition.

Almost looks like what you'd expect if the wrong powder were used.

All rounds were loaded at the same time, with the same powder. H3335 23.5 grains. I don't do hot loads. Someone said a stainless steel pin could have been lodged in the brass, that I didn't see? That could cause this?

 

[writerman]

This topic seems to be way more important to us than the OP, His last visit was the same time stamp as the post.

Sorry. I checked off the 'email me replies' box and got none, so I didn't know there were responses.

 

[writerman]

WAG, the 51st fired round may not have been the 51st round reloaded, could have been the 1st reloaded. A previous posted comment indicated a different powder was in his auto powder dispenser, wonder if was a similar solution, maybe 4-5 gas of overlooked pistol powder?

Same powder. I always only load one batch with one powder, all at the same time, and then clean out the loader. Always measure, never load hot. All rounds loaded the same with the same specs. Someone mentioned a stainless steel pin could have been lodged in the brass and that might have caused this?

 

[writerman]

Over pressure 100%, there would not be that much brass flow into the ejector hole if
it was out of battery.

"One of the best gunsmiths in town said he thought it might have been something about the round the gun didn't like"

Now that is is funny, that something was the 80,000 pressure the breach experienced
so yea the gun did not like it.

Overpressure. Yes. But how? Why? I would really like this to not happen again. LOL! Destroyed the whole rifle, cracked the barrel extention in half, split the bolt, cracked upper and lower, not to mention it was not fun. Loaded PAC with 23.5 grains of H3335 OAL 2.245, 55 grain .223 all the same batch. It was the ONLY PAC in the batch, however, all the rest were Winchester. I was thinking, maybe the walls of the PAC are different, less case capacity? That might cause overpressure?

 

[writerman]

That’s where brass flowed into the ejector.
Doesn’t look OOB to me. Everything I see there looks like an extreme over pressure incident. The commenter above who noted the ring on the case mouth may be onto something… maybe.

I don’t think we’ll solve it from a picture on the web, but something caused that round to have a greatly increased pressure compared to the others. Could have been case too long as noted above, or the bullet got pushed back, or too much powder. If this is part of a lot as stated unlikely that it was the wrong powder. I can’t think of anything else that would increase the pressure that much. (Though I’m surprised nobody has brought up the usual suspect of a carbon ring that seems the be the www answer to all reload woes)

Once upon a time a long time ago I had a 308 with a tight necked chamber. I forgot about that and I am sure I came close to a story to tell shooting M80 ball one afternoon.

All cases always measured. Inspected for any defects and defected cases tossed. 23.5 grains of H335 OAL 2.245 55 grain FMJ. No over pressure signs on any of the other spent round, no cratering. Not a slam fire, pulled the trigger and bam! Was a PAC brass case, all the others were Winchester. I am trying my best to figure this out so it doesn't happen again. Gun was trashed. Even split the barrel extention all the way. That surprised me.

 

[writerman]

WAG, the 51st fired round may not have been the 51st round reloaded, could have been the 1st reloaded. A previous posted comment indicated a different powder was in his auto powder dispenser, wonder if was a similar solution, maybe 4-5 gas of overlooked pistol powder?

That 'different powder' was in reference to a friend of his. This was all the same powder, no question. I load one powder, throw them into one bag, and mark the specs. Always measure, always check, check, check. I am leaning toward some obstruction/blockage, but how? Not a squibb load, pulled the trigger and bam! so not a slam fire either.

 

[writerman]

I don't think you can state that as fact without more info. Logic tells me that if that were true, ALL of the rounds fired would exhibit similar failures. Thin at the web or not, if the case is not supported adequately at the extension, it will most likely fail. The OP, while reticent with his follow-up comments, made no mention that this was a new barrel. If it wasn't, why didn't this occur earlier? I will say that I don't believe this to be the problem.

Reticent because I checked the 'notify me of replies' and nothing came through. Sorry. This was a fairly new barrel, only about 1500 rounds shot through it, no problems. My favorite .223 highly accurate, 24" fluted bull barrel. )&*%*&! I am still trying to figure this out. Others have said that it wasn't an out of battery firing, but how else could that damage happen, if the brass wasn't outside of the chamber when it blew? Trashed the whole rifle.

 

[writerman]

Looking at the neck, it seems a bit short. Possibly the shoulder moved forward too, due to the wear just below it. Potentially a different weight/longer bullet got mixed in, stuffed into the lands on an already hot reload, soft primer like a WSR and caused a slam fire and overpressure.

Only time I've seen anything like this was also a 223, but a R700. Older gentleman a couple benches over just firing away at a pretty good rate. Like he was determined to shoot 200 rounds and be home for lunch. Then one really big bang! Gun did what it was supposed to do, vented gas and contained it. Case head extruded into and completely filled the bolt face. Took some serious prying with pliers to get it out for him. I told him to get the bolt checked, but he looked it over said it was fine and went right back to shooting as fast the the RSO would allow. He must have shot another 75-100 rounds after that. Packed up and went home. Never even pulled his target.

If it was a different weight bullet, it came out of one single box.

 

[writerman]

1. If the OP would do it, a careful cross section of that case might reveal a too thin case wall,
or signs of a case stretched case ring -very thoroughly covered in other threads.

2. The very pronounced ring just above the separation (almost looks like a pipe cutter did it)
does strongly suggest an incorrect forcing cone cut, which might have combined with a
too thin case wall; but, it would also seem that would have become evident in earlier firings.

3. Did not see any mention of the brass -was it a first reload on the OP's 1F brass, range pickup, or?

4. Powder measure: Last year, a local shooter totally disintegrated a CA MPR 6.5 Creedmoor.
He has decades of reloading experience, and has stopped discussing the event. But, I strongly
suspect the mentioned probability of a wrong powder left in the measure or trickler chamber.
If he had not had his left hand squeezing the rear bag, he absolutely would be missing fingers.

He was honest to admit to the rifle manufacturer that he was using handloads -and he said (it
seemed to him), they could not hang up fast enough. In no way am I faulting the mfg for that.

Tell me what pics you need please. Same powder, all rounds. 100 reloaded, first fifty great. 23.5 grains of h335, OAL 2.245, always measure my cases, always inspect the brass. PAC brass.

 

[Fast14riot]

If it was a different weight bullet, it came out of one single box.

I've found different caliber bullets in the same box before. Especially those red boxes.

 

[tommeboy]

Have you read what I said? You had a bad piece of brass with a defective barrel. Thats it. Thats what happened. Throw away all of that brass. For one I have never heard of it.So that right there is suspect.

Wipe up your tears and buy new stuff.

 

[JerkyFreak]

Is the bullet still in the barre?

Could the previous shot have been a squib causing a barrel obstruction?

Could a heavier bullet made it's way into your reloading area?

Do you load with a progressive press or single stage?

I doubt that one stainless pin would cause that much overpressure.

 

[itchyTF]

Do you have a borescope? Inspect the chamber and bore for any anomoly / indentations that don’t belong there.

 

[M-61]

Trashed the whole rifle

Surely you have a pic of the rifle.
Post a clear one if you can, not a ‘sheety’ one.

 

[brokeasajoke]

Have you read what I said? You had a bad piece of brass with a defective barrel. Thats it. Thats what happened. Throw away all of that brass. For one I have never heard of it.So that right there is suspect.

Wipe up your tears and buy new stuff.

Could you elaborate on defective barrel?

 

[M-61]

Have you read what I said? You had a bad piece of brass with a defective barrel. Thats it

I didn’t realize some people have actually examined the rifle and brass.
I have not.
I’m out of this mess

 

[tommeboy]

Could you elaborate on defective barrel?

the cone on the face of the barrel was cut too deep and a piece of brass that the web was too low created a unsupported casehead and it blew the brass out. This stuff happens all the time. But usually it just leaves a belt around the brass. Everyone always goes right to you loaded the cartridge too hot.

I have been in way too many conversations with people when this happens. Go back and read everything I have posted.

Im done

 

[rwj]

What else could it be? Fifty rounds fine, at fifty one, pulled the trigger and bam! Not a case of squibb load or overloading, or slam fire.

Many possibilities have been identified in this thread. Dismissing them all is your prerogative. Best wishes moving forward…

 

[JerkyFreak]

The amount of brass extruded into the ejector hole alone points to a very hot load. This is not a smear or shiny spot. This could only happen with pressure well in excess of 65kpsi.

 

[Herzo]

I know, but from what possibly?

I had a pressure excursion on a 260 Remington a year or so ago. Blew the primer on a once fired case. All charges were individually weighed. My only conclusion (unprovable) was that I failed to completely clear all the tumbling media from the case?