AR blowup

[CJ6]

Lyman goes up to 27.

Bolt gun or AR data?

 

[writerman]

Are you sure that the powder has not been contaminated by someone accidentally putting a fast burning powder in it?

If I had a situation where my gun blew up, and everything measured correctly, the first thing I would blame is the powder.

All my powder has been bought new, and is separated in clearly marked original containers. It was definitely H335.

 

[writerman]

What do you mean when you say we tested the powder? How did you test it? Is the powder commercially packaged H335 or milsurp pulldown. Did you check the bullet dia with a mic? Bad brass? Unsupported case head in the chamber? Maybe an issue with the rifles not the ammo?

Thing is, other than this reloaded box of 250 rounds, the rifles had been fired lots before, no problems.

 

[writerman]

Have you measured your chamber? If the barrels from the two blown up rifles are still around.
The reason I ask is if the chamber were right at 1.760, the cases that are 1.765 would be crimped by the throat and cause higher pressure.
Brownells sells a really cheap chamber measure.
If you have a borescope you can insert a case into the chamber and insert the borescope from the muzzle.

Can only find case measures, not chamber measures anywhere, even Brownells.

 

[writerman]

The bold print is conflicting.

Just like in the last thread where the gun blew up, your load is suspect. The last one blew up with less powder, loaded to a longer length. So this load was hotter than the last. And again the charge weight was over max in some data, and a starting load in others.

One more piece of information is trim length. 1.765” is over max length. At that length, a cartridge with 0 headspace could have as little as .007” clearance from the end of the neck to the the transition taper in the chamber to bullet diameter. There the case neck will pinch the bullet and cause a pressure spike.

New brass, or brass sized with the die touching the shell holder for maximum headspace, will most likely give you brass that is at or below minimum spec. About .010” shorter than max length.

What that will allow is for the case to move forward in the chamber .010”, where you have .007” clearance. Effectively headspacing off the rim of the neck. Then the neck stretches when fired creating a tighter crimp.

Overcharging and crimping the bullet in the chamber due to Long brass is a pretty likely answer.

I was thinking after reading so much, that a number of variables might have happened. A charge on the high side, yet not over published specs, along with smaller volume military brass, and then the longer case crimping causing a pressure spike. Even with those variables, would that cause the bolt carrier to split, the upper crack, and the ejector to fly out? Along with a destroyed magazine. Maybe the small variances just added up?

 

[whatsupdoc]

OP, you need to post good quality pictures of the bolt the barrel extension
case and related parts.

In your first post you wrote that one rifle blew up then a second rifle blew up,
is that correct the two rifles were destroyed by the handloads?

Did you use picked up range brass, because it is possible that some of the cases
were reloaded multiple times and the case head stretched and thinned.
You fired them in your rifle and the head let go and BOOM.

 

[Doom]

Without photos it's impossible to go forward with anything but conjecture. The loads do not seem to be excessive but it the rounds were left in bright sun on a hot day then its possible its overpressure. It's also important to know which primers were used in the rounds. The pictures also need to include photos of the cases and the bolt lugs.

 

[mike mccormick]

Hey, I am willing to learn. I just wanted facts and personal experiences. According to all the data I have read, none of those variables should have caused this. You can bet, I will be more meticulous in further reloading, and I am going to trim under spec, like the new brass you get. No more mixed brass, I'm going to start with new. Defensive because I wanted information or comments like yours, not someone's opinion of 'double charges' which they were hardly that. They were all within book specs. I always start two grains under max. and usually stay there. Lyman goes up to 27 so I don't see the problem. Do you think it might have been a long case that crimped in the chamber, and still locked up? I have read numerous reloaders who load up to 1.800 and they have had no problems. I don't get it, but I won't do that. How do you 'test fire' a charge weight safely?

Yes,it is possible that a long case could have caused it. Realize also, that inconsistent lengths also cause inconsistent crimp force. If your die was set to properly crimp a case at 1.755, and you run in a case at 1.765, much greater crimp force is applied. Regardless of what you have been told, 223 brass will rarely chamber much past 1.770, and the brass has been stretched so far by then that case head separation is likely. The reloading specs are there for a reason. Internet BS is just that.

 

[Bill K]

AR.service rifle, same as .223 Rem say max length of case 1.760 and trim length 1.750. It would appear that your case is over specs, then add a max load, for which your chamber could not handle and it jamming into the lead/lands you created a bomb for both of the rifles you shot them in. Result blown chamber/rifle.

 

[paperpuncher]

Have you ever had this happen, and what happe

Have I ever had what happen?

Commercially packaged in the bottle right from Midway.

Did you contact Hogdon?

 

[dellet]

What information do you need, and have you ever had this happen?

I was thinking after reading so much, that a number of variables might have happened. A charge on the high side, yet not over published specs, along with smaller volume military brass, and then the longer case crimping causing a pressure spike. Even with those variables, would that cause the bolt carrier to split, the upper crack, and the ejector to fly out? Along with a destroyed magazine. Maybe the small variances just added up?

I really don’t need any more data or info. Between the two threads I think it’s clearly a load problem. The question is what.

When you look at various load data, 23 grains and a 55 grain bullet can be a starting load, or a max load depending on the actual bullet and seated depth. That says that following guide is very important and substituting components and measurements is critical.

With the numbers you provided, the first load the bullet was seated at 2,45” with 23.5 grains and blew up a rifle. The second load was 23.5-25 grains seated at 2.05” with brass so long that potentially could pinch in the chamber due to length and base to shoulder measurement. This means the second load was higher pressure than the first load. Or maybe. Just the same variables with more information. Again the rifle blew up.

So now you have the same components, assembled in a way to create more pressure, and another blown up rifle. Something about doing the same thing over and over expecting different results come to mind.

The powder charge should be safe, at least to the point of expect maybe a popped primer over pressure symptom. Not catastrophic failure pressure.

That gives me enough reason to question the powder. Your loads are a problem, but I would not expect the near fatal results you’ve had. I think it’s the wrong powder or it’s gone bad. Either way not worth the effort of loading anything with it again.
Disregard the above if this is a fresh container and not what you used to last time.

I’m sure Hodgdon would love to have that powder back. If they sold mis labels powder, they want it off the streets. If they can prove the powder was contaminated , they can avoid liability. This is how recalls start.

If you look at my posts in your other thread, I posted a photo of what roughly 125-130,000 psi does to an AR upper. Yes, I have experience blowing one up.

I’m not sure H335 can develop that kind of pressure with 25 grains without another problem or two. But a pinched bullet can act just like a blocked barrel.

Again I think the powder may be suspect, but your loading process is without doubt guilty.

 

[mmcu]

Would a case length cause that though? I read lots of threads of guys who don't even trim. They shoot up to 1.800 with no problems. For 250 rounds I weight the first three charges and throw the rest, because usually H335 is close enough to spec, and since the charge weight is 23.5 and Lyman goes up to 27 grains, I figure one grain off isn't goind to cause this. I have to go back and measure BOTH chambers now. The first rifle I rebuilt and immediately went out and successfully shot 20 rounds of H335 at 22 grains. Have you ever had this happen?

Have I personally blown up not just one gun, but two? No.

Have I seen similar events take place? Yes.

In each instance, it was due to someone who simply didn't pay attention to details.

In the absence of any information other than your original post and the one that I'm responding to, I'd speculate that you are the victim of your own oversights. Not trying to be an ass, just simply stating what I see as obvious and trying to keep you from hurting yourself.

In summary: 1) Your charge weights are all over the place, 2) Using mixed military and commercial brass with dissimilar characteristics, 3) Using cases that exceed maximum lengths all add up in a cumulative way to what happened to you not only once, but twice.

I'd be cautious about listening to folks that say things like "they shoot up to 1.800 with no problems" and running with that advice. Know what your chamber dimensions are and conform to those limitations.

Lastly, using your own words. "Close enough..." and "figure one grain..." are phrases that should never be part of your vocabulary when reloading ammunition.

 

[M-61]

Two different AR 15’s blown up with the same load.

Let’s blame the rifle.

Yup
That solves it

 

[jds holler]

Bolt gun or AR data?

Lyman manual uses Colt AR15 universal receiver. jd

 

[jds holler]

Just for curiosity, were you loading with progressive or single stage?? jd

 

[dhagerty40]

I have to ask, Did you Swage the primer pockets on the military brass?

I will not get into anything else..... most has already been covered..

 

[Fast14riot]

Is H335 slow enough that a severe under charge would cause a pressure spike, like some magnum powders?

 

[Rsadams]

Did you load pistol before loading this rifle ammo... Because it sounds like some pistol powder got mixed in... Reloading is safe but certain rules just have to be followed... Having that much swing in powder weights is certainly not good... Until I figured that out I wouldn't be loading anything....

If you did load some pistol before and some powder got left mistakenly in the hopper keep in mind if you dumped that back into the powder bottle it's ruined and extremely dangerous... Throw it out immediately...
I personally don't think using mixed brass would cause this serious kaboom but it could something like blown primers on hot loads.... In the middle of the charge range I don't see it happening , that's just my opinion take it for what it cost you...

I am seeing people post all kinds of different max charges I haven't looked it up myself but this is exactly why one rule you must follow is start low on the scale and work up till you get what you want checking for ANY pressure signs as you go... You didn't just have a slight over pressure you had a serious explosion that could have been deadly not once but twice... With those charge weights you listed I don't see it causing that big of an explosion without pistol powder or a barrel obstruction... I find it hard to believe you had two barrel obstructions unless you are extremely careless but the pistol powder is far more plausible.... Once again this is just my opinion on the matter but DO NOT use that powder again and you should seriously go buy a lottery ticket because you got very lucky TWICE...

 

[Intell]

I blew up a new Armalite not long after IMR went from metal to plastic jugs.
I mistakenly grabbed a jug of IMR4227 instead of H335.
I always used IMR for pistols and was used to it being in the metal cans.
Parts flew everywhere the upper bananaed around the port blew out the mag and I wore the bolt release print on my left arm for the better part of a year.
Your kaboom sounds like mine, pistol powder.

 

[jds holler]

For right now, my vote goes with "over length case-crimp in chamber".

That being said, the variance in charge weights is horrible considering how accurately H335 goes through a measure. Right now, I'm charging cases with BLC2, which is almost identical, and I'm getting a 0.1 gr. variance factor. 1.0 gr. is horrible, and would be even with a Lee powder scoop. jd