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Posted: 7/14/2013 9:20:45 PM EDT
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So I was at a competition today and while conducting a course of fire I had an unusual feeling shot followed by a huge cloud of smoke blown back in my face (along with all kinds of small particles). I glanced down at the magazine and the floor plate had entirely been removed with the spring sticking out. I removed the magazine to clear the rifle and smoke was pouring out of the mag. When I cleared the chamber, the casing was ejected as the rifle hadn't cycled. I checked the case and, lo and behold, it had ruptured just above the rim in a semicircle around the case's circumference. It should be noted that I had a double feed a few shots before that round went off. In fact, it was the only malfunction the rifle has ever had since I have owned it for the past 6 years. I don't know if that reflects on the construction of the ammunition that may have led to the rupture.
I'd like to know if anyone knows how to identify any problems with my ammunition. I have a batch that I inherited from a recently deceased relative, and it seems to be a mixed collection of newly purchased and what may possibly be reloaded ammo. He didn't reload rounds himself, but he did go to gun shows regularly and may have gotten some shoddy ammo. The ammo all looks to be in ok condition, and that was the only problem round. Some rounds are soft nose, most are FMJ. Some seem to have a longer and narrower projectile than the normal ones. Regardless, all are .223/5.56mm. The only explanations I can think of are that either the casing had become reloaded too many times or the round had too much powder. The shot didn't have any extra perceived recoil, though that may not mean much since the force of the shot went out through the magazine. I really wish I kept the case, but I was rushed off the range to keep everything moving smoothly. Also, I'm worried about the condition of the chamber and bolt of my rifle. Everything appears to be in working order, but I didn't want to shoot any more ammo through it today. The only thing I noticed was that it was suddenly bone dry and had a strange coppery color coating the bolt, BCG, and interior of the upper. Granted, I assume this is from the brass rupturing. Would there possibly be any damage done to the chamber or bolt, or should I not worry? I appreciate any advice anyone has to share. |
| You should be able to see any damage with a visual inspection, since you were able to clear the rifle so easily I wouldn't be terribly concerned. You may have had a weak case let go, especially if it didn't even try to cycle. Your other possibility is some stupid load with pistol powder or something that wasn't enough pressure left at the port to cycle the rifle but pressure peaked quick enough to blow the case out. Bottom line, I'd ditch the sketchy ammo. I don't ever shoot gun show reloads or any other reloads but my own. |
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My first inclination would be to replace the bolt assembly.
You could clean the bolt thoroughly and look for cracks with magnification. Inspect the tip of the firing pin with magnification. I would expect the extractor to have some damage. There are tests that can be run, but it would cost you more for the test than replacing the bolt. Don’t shoot unknown ammo. Ever. |
| Thanks for the advice. I feel stupid about it now, but when I looked through the ammo he had for his guns most of it was store bought stuff and I didn't realize any of it would be reloads. I will start the process of going through all of it and making sure to get rid of the reloaded stuff. |
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Case head separation. This is common on brass that has been reloaded too many times, especially USGI brass that was fired in long headspaced machineguns.
It is always good to run a headspace check and make sure yours wont close on a Colt Field II gauge, but that's about it. Don't worry. And don't shoot other people's reloads. |
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the 'bone dry' is the result of the 'flame' traveling over the surfaces and out the magazine... the flame burns off the bolt lubrication... look around at the "kaboom" threads... a common observance in the images posted in each thread.
"is is possible" one of your miss-feeds resulted in a bullet set back? glad you and range personnel are OK. |
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The only time I have seen a case rupture has been in M249s actually.
Anyways, not to beat a dead horse but I've found a strange thing about these reloaded rounds that I didn't notice until I compared them to the store bought ones. The bullets on them are not normal looking 5.56 projectiles. I tried looking online and have not found any that look like this that are actual 5.56mm rounds. They are a tad thinner, longer and straighter/pointer (almost like a pencil point) than the regular 5.56mm rounds if that makes any sense. It's almost as if a 5.45 had been crimped into a 5.56 casing or something. The difference is slight and may not be anything, but again I'd like some opinions. The differences are much more glaring in person. http://s16.postimg.org/mhhqk5fwl/IMG_20130716_213537_970.jpg http://s12.postimg.org/f5luefmdp/IMG_20130716_213714_127.jpg |
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When you say "doesn't look like 5.56" that doesn't mean anything.
5.56 is a generic term, to describe "beyond SAAMI pressure", or a specific military designation, such as M193, M196, M855, M856, MK262Mod1, MK318Mod0. Since that is a reload of unknown origin, it could be just about any bullet from a number of manufacturers. Though, from the picture, that looks a lot like a pulled and tumbled M855 bullet, assuming it is FMJ. |
| I didn't mean specifically the SAAMI 5.56mm definition but literally just any .223/5.56 round. I've used nearly every round you listed as well as numerous types of .223/5.56 commercial rounds and none of them had a projectile shaped like this. I've never seen it before, and that's why I asked if anyone had. It has almost no tapering to the bullet's shape. Most .223/5.56 rounds have generally the same shape but this one is totally different. I apologize for picture quality. |
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could be a brand to brand thing. heck I've seen glaring difference on winchester fmj's in the same box, presumably stamped out on 2 different machines with different dies.
could also be some 55 and 62 grain pull downs mixed together and then reloaded. Pull some down and weight them. Might even have tumbled tracers with the paint worn off. I only shoot my own reloads no unknown junk. 
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At least we can all be happy that you are safe!
As for your rifle... I would check your BCG, barrel, and chamber. Look for cracks or and "chunks" missing. Also look for warping in your barrel. You can see warping by looking for a bulge towards the chamber end of your barrel. Also, by looking down the barrel (disattached from the receiver) check the rifling to see if there is any warping or oddities. If everything checks out, then go ahead and shoot it. Rifles are a lot more durable than people give them credit for. They are not delicate devices and can be used and abused. |
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