AR blowup

[Rsadams]

I took the firearms to two professionals. One shook his head and said 'it will happen if you reload enough.' The other took apart all the remaining rounds and also shook his head, saying that given the varying specs, none of them would or should have caused this to happen. I don't care where the fault it, I just want to as definitively know as much as I can, so I don't do this again. Thanks. I will post pics.

The if you reload enough thing is absolutely wrong.... If you follow the rules you will never have a problem....

 

[jelenko]

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

Here you go:
https://www.brownells.com/reloading...s/sinclair-chamber-length-gage/?sku=749000811

 

[Jon Leary]

In my experience h335 is heat sensitive. I developed a load for my 308 with 125 sierra bullets and it was fine then I shot it on a hot day and it pierced the primer.

 

[Webster]

I loaded 250 rounds of 55 grain Sierra FMJ spire point, with 23.5 grains of H335. OAL 2.200. Case length 1.760. I had a rifle blow up. Then I took apart some rounds and they were all within spec. Went to the range. Another rifle blew up. I took apart all 250 rounds and they were from 23.4-25 grains, all within published specs. All the cases were from 1.755 to 1.765. All the OAL's were close to 2.200, some shorter, some longer, but none off by more than a couple of thousandths. All within published specs. Went to a reloading expert who took apart and measured everything and could not come up with an answer. We even tested the powder. Some were military brass. All were lightly crimped. I would like to know of anyone who has had a similar experience, and who actually discovered what happened? Not interested in more bleating about 'double charges' it wasn't, or 'you did something wrong, it's all your fault' that doesn't help. What would help would be actual answers and actual personal experiences. Thanks.

Why did you shoot the same load in 2 rifles? You ruined 2 good rifles? That may eliminate the rifle. Not likely you had a bore obstruction in 2 rifles. Not considering things like cartridge length the only thing remaining is the powder type and charge. Extremely high pressure is the only thing that can blow up a rifle. All reloading manuals are different, some are similar some have big differences. Almost all reloading manual data is for bolt action rifles only. Sounds like you used a very stiff charge for your rifle, Even if you were a little over a max load for your rifle it shouldn’t blow it up. More likely some kind of powder mix up. You need to buy a new rifle and a new can of powder appropriate for your cartridge (bolt or semi-action) and start at minimum charge. Bolt action rifles are a lot friendlier for a beginner reloader and probably more accurate. You didn't mention the caliber, I assume it's a 223.

I hope you wear good shooting safety goggles your only issued 1 set of eyes.

 

[writerman]

Bolt gun or AR data?

Specifically for AR my AR reloading manual goes to 26.

 

[tactserv]

When the AR "Blew Up", did the case head blow out, and hot gas into the mag/magwell and out the ejection port? Or did the barrel split at the chamber?

Sure sounds like the round went off out-of battery. High primers, sometimes slam fires due to floating firing pins, and soft primers have all been blamed for the issue you described.

As a general rule, with too hot loads in an AR style rifle, you will see signs before booms. Smeared case heads, extractor tears on the rims, or case head separation/blown primers.

Note there are heavy cup primers made for AR style rifles, made in part to avoid out of battery booms.

 

[762willdo]

Something stinks here…..

 

[writerman]

I think I have figured it out. It was a series of mistakes I will never make again. I built two AR's for a close friend, one of them being a .223. Well, he went out and bought 1000 rounds of once fired military brass. First problem, the cases are slightly less in volume, so produce more pressure. Then even though he was an experienced reloader, he had no case guage for .223 and did not measure his cases. These were the first two AR's he owned. He was getting on in years and passed four weeks or so ago. That's when I bought a lot of 1000 primed .223 cases from his estate, and promptly loaded them. I DID NOT CHECK CASE LENGTH. Second mistake. Some were nearly 1.780. This is why I was puzzled when I found cartridges overlength in my stuff, when I always measure. But I incorrectly assumed that he had measured them, because he had fifty years of reloading experience. I figured incorrectly that they had been measured, since I always measure and trim before I prime. My bad. Maybe he bought them pre-primed, I don't know, I never will. I should have measured them. That whole bad bag was all stuff from his estate. The combination of military brass and overlength I believe is what did it. The cases crimped when fired causing what was a mimic of a squibb in the chamber, blowing out the back of the brass and destroying the rifles. Had I trimmed the cases, given the loads even with the variances, they would have been fine. Never, ever, trust reloading from anyone else, period. That was the lesson. I got it. They were all either 25 grains of H335 or under, and my AR manual specifically lists 26 grains as max. for an AR. I am going back through all 1000 rounds and measuring each one with my Wilson Case guage, and pulling any one of them 1760 over. The powder wasn't the problem so I'm saving it and using it to reload all the correct length cases now. What a huge job. But I like my face. Thanks for all the replies.

 

[jelenko]

23.4-25

To several other's point, 1.6 grains variation in powder charge is huge.
How was the powder charge made for the cartridges? With that much variation, it seems possible that the ones that blew up the rifle were more than 25 grains - maybe a lot more.

Also, what is the actual name of the bullet that Sierra uses? I couldn't find a "55 grain Sierra FMJ spire point".
The reason I ask, is Hodgdon shows a max of 22.7/22.8 for a couple 55 grain 223 bullets. That 3 grains difference would go a long way toward an unintentional, rapid disassembly.

 

[writerman]

When the AR "Blew Up", did the case head blow out, and hot gas into the mag/magwell and out the ejection port? Or did the barrel split at the chamber?

Sure sounds like the round went off out-of battery. High primers, sometimes slam fires due to floating firing pins, and soft primers have all been blamed for the issue you described.

As a general rule, with too hot loads in an AR style rifle, you will see signs before booms. Smeared case heads, extractor tears on the rims, or case head separation/blown primers.

Note there are heavy cup primers made for AR style rifles, made in part to avoid out of battery booms.

Read my reply. I think I figured it out. My rifles had been used for hundreds of rounds before this, so out of battery which is what I first thought it was, is unlikely.

 

[writerman]

To several other's point, 1.6 grains variation in powder charge is huge.
How was the powder charge made for the cartridges? With that much variation, it seems possible that the ones that blew up the rifle were more than 25 grains - maybe a lot more.

Also, what is the actual name of the bullet that Sierra uses? I couldn't find a "55 grain Sierra FMJ spire point".
The reason I ask, is Hodgdon shows a max of 22.7/22.8 for a couple 55 grain 223 bullets. That 3 grains difference would go a long way toward an unintentional, rapid disassembly.

My AR manual lists 26 grains as max for a 55 grain spire point. It's figures specifically for an AR. Read my last reply, I think I figured it out. Even with the variations in powder, that was not what I believe caused it.

 

[writerman]

Bolt gun or AR data?

I use AR data, from an AR loading book. They max at 26 grains.

 

[writerman]

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.

Yep. Thanks. Read my last post about what I think happened.

 

[writerman]

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

Single stage. One bullet at a time.

 

[CJ6]

Data from manuals are setup with specific components. Case brand, bullet brand, primer brand and type. Variation in these alters the end result (High or Low pressures).

 

[karrarararararar]

I think I have figured it out. It was a series of mistakes I will never make again. I built two AR's for a close friend, one of them being a .223. Well, he went out and bought 1000 rounds of once fired military brass. First problem, the cases are slightly less in volume, so produce more pressure. Then even though he was an experienced reloader, he had no case guage for .223 and did not measure his cases. These were the first two AR's he owned. He was getting on in years and passed four weeks or so ago. That's when I bought a lot of 1000 primed .223 cases from his estate, and promptly loaded them. I DID NOT CHECK CASE LENGTH. Second mistake. Some were nearly 1.780. This is why I was puzzled when I found cartridges overlength in my stuff, when I always measure. But I incorrectly assumed that he had measured them, because he had fifty years of reloading experience. I figured incorrectly that they had been measured, since I always measure and trim before I prime. My bad. Maybe he bought them pre-primed, I don't know, I never will. I should have measured them. That whole bad bag was all stuff from his estate. The combination of military brass and overlength I believe is what did it. The cases crimped when fired causing what was a mimic of a squibb in the chamber, blowing out the back of the brass and destroying the rifles. Had I trimmed the cases, given the loads even with the variances, they would have been fine. Never, ever, trust reloading from anyone else, period. That was the lesson. I got it. They were all either 25 grains of H335 or under, and my AR manual specifically lists 26 grains as max. for an AR. I am going back through all 1000 rounds and measuring each one with my Wilson Case guage, and pulling any one of them 1760 over. The powder wasn't the problem so I'm saving it and using it to reload all the correct length cases now. What a huge job. But I like my face. Thanks for all the replies.

5.56 military brass has more capacity than commercial brass, not less. That is a wives tale carried over from 308/7.62 that doesn't apply to 223/5.56

 

[tmwinds]

Do you load or have any.300 Black Out ammunition?

 

[dellet]

I think I have figured it out. It was a series of mistakes I will never make again. I built two AR's for a close friend, one of them being a .223. Well, he went out and bought 1000 rounds of once fired military brass. First problem, the cases are slightly less in volume, so produce more pressure. Then even though he was an experienced reloader, he had no case guage for .223 and did not measure his cases. These were the first two AR's he owned. He was getting on in years and passed four weeks or so ago. That's when I bought a lot of 1000 primed .223 cases from his estate, and promptly loaded them. I DID NOT CHECK CASE LENGTH. Second mistake. Some were nearly 1.780. This is why I was puzzled when I found cartridges overlength in my stuff, when I always measure. But I incorrectly assumed that he had measured them, because he had fifty years of reloading experience. I figured incorrectly that they had been measured, since I always measure and trim before I prime. My bad. Maybe he bought them pre-primed, I don't know, I never will. I should have measured them. That whole bad bag was all stuff from his estate. The combination of military brass and overlength I believe is what did it. The cases crimped when fired causing what was a mimic of a squibb in the chamber, blowing out the back of the brass and destroying the rifles. Had I trimmed the cases, given the loads even with the variances, they would have been fine. Never, ever, trust reloading from anyone else, period. That was the lesson. I got it. They were all either 25 grains of H335 or under, and my AR manual specifically lists 26 grains as max. for an AR. I am going back through all 1000 rounds and measuring each one with my Wilson Case guage, and pulling any one of them 1760 over. The powder wasn't the problem so I'm saving it and using it to reload all the correct length cases now. What a huge job. But I like my face. Thanks for all the replies.

Looks like you might have a good handle on it. You screwed up, you trusted someone else. Didn’t listen to some others who tried to help

As for penance, go back through both threads and count the number of times you stated “in spec” or “measures right”.

You also might consider moving to a different town. If both the best gunsmith and the best reloader both missed a pretty rookie mistake, none of the shooting ranges in the area are safe
Only you can keep yourself safe. Good you stuck with it

 

[jds holler]

I'm gonna say that I'm also using H335 in my new AR, and as per a suggestion from a member here, I went down from 25 gr. to 24,(55 gr. Max) getting a measured velocity of 2950+/_ a few fps. Accuracy is better (one inch-ish at 100) than with the hotter load. (as he said it might be) -- AND I always like going for greater margin of error, especially when I might want to use a batch of skanky old pick-up brass of bastard linage. jd

 

[CJ6]

5.56 military brass has more capacity than commercial brass, not less. That is a wives tale carried over from 308/7.62 that doesn't apply to 223/5.56

I don't know about that.... I have some IMI 5.56 that has considerably less internal volume than the same period (late 90s) Winchester brass.