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Posted: 4/5/2008 11:51:55 PM EDT
**UPDATE**
**Well Remington is taking care of it. Even though they could find nothing wrong with any of the 8 boxes I returned they are having the gun fixed on their dime. "In regards to your gun repair, we will be working with CMMG directly to cover all associated repair costs that occurred with this issue." Throughout the process Remington has been attentive and straightforward. Nice to see a company take care of it's customers, doesn't happen much anymore. And just a note, they do monitor the gun forums, and they do care what their customers think. Thanks for all the input and thanks to Remington for getting it done.** So we head out to kill some zombies today, taking the new CMMG bargain bin along. Load up 1 Pmag with new Rem UMC 223 55gr. It shoots like a dream. 20 min later my bro loads the same ammo into the same mag...fires 1 round and the entire mag blows. Lucky he's ok as it blew straight out the bottom of the mag. Between the bang and his reaction I thought he blew his damn arm off. Now the BCG is LOCKED\JAMMED full forward. Can't pull it back with the charging handle. Tried to "persuade" it back..no go. It's almost as if the front of the bolt has spun and the keys are catching. Obviously I need to send it back to CMMG but in the interm I'm trying to figure out WTF. Any ideas would be greatly appreciated. Pics of the mag..lower and upper as it sits..thats as far as the CH/BCG will come out Basic field strip prior to firing and all was good. Hell the damn gun looks brand new As far as the gun specs it was the latest offering CMMG bargin bin 16" M4 Non chromed 1\9 CCMG lower unknown upper..only marking is a "keyhole" marking = cerro forge? correct M4 feedramps So anyone..WTF over??     Well it's apart now....ugly  Failure at the extractor So I guess the question is..what was the cause? The ammo or the extractor?     |
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Posted: 4/6/2008 12:01:30 AM EDT
[#1]
ouch, wish I had some help for yah.
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Posted: 4/6/2008 12:27:37 AM EDT
[#2]
Since CMMG doesn't give the bargain rifles a warranty, what are the chances they'll fix or replace your rifle without you going out-of-pocket on shipping and labor?
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Posted: 4/6/2008 12:34:53 AM EDT
[#3]
Sounds like an ammunition induced failure. Is the lower intact?
Save the rest of the ammo out of that box, and note the lot number if any. Then advise the ammo company as well as CMMG. |
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Posted: 4/6/2008 12:35:36 AM EDT
[#4]
1st off, sorry about the kB!...that sucks
 2nd, its a "mag" not 'clip'  3rd, i'd be more than 99% sure that it was ammo failure...FWIW: UMC is one of the suckiest factory ammos out there w/ several known cases of case failures, bullet setbacks, etc  i'd contact CMMG, but i doubt they can do anything....the only folk who might be able to do anything for you would be Remington, since it was thier ammo, BUT it will be tough pressed to prove they were at fault--contact em both anyways, note ammo lot # and where you got it, save ALL the stuff you have left, etc the keyhole is simply a forge marking--lots of the top quality AR manf use that upper good luck, i hope everything works out ETA: your lower is probably ok and will still function fine (double check it anyways), but your upper might be FUBARed and require armory work and parts replacing (bbl, upper, bolt, etc) |
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Posted: 4/6/2008 12:51:11 AM EDT
[#5]
Id bet that the bolt is snapped at the cam pin hole, causing the lugs on the bolt to be miss aligned inside the bbl extension. You might have to carefully(not using much force) try to rotate the bolt....not carrier to unlock it from the feed ramp area and bbl ext. It will be tough, and you might need some kind of little rod to sick in the ejection port to try and spin the bolt while pulling the handle back.
ETA- Can you be sure that a cartrige isnt stuck in the bbl??? MAKE SURE THE UPPER ISNT STILL HOLDING A LIVE ROUND!!!!! Then maybe try pulling the CH real hard. It may just be stuck real tight. |
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Posted: 4/6/2008 1:07:02 AM EDT
[#6]
fixed "clip" i know better :)
Lower is good to go shot 250+ more rounds through the colt and the sig 556 no problems No live round in the upper..checked that VERY carefully no amount of pulling on the CH will budge it My guess is CCMG will tell me to pound sand Snapped bolt sounds about right So now what..pull the barrel and attack it from the front end? And here I was thinking I was being nice to it and not shooting the Silver Bear or Wolf through it  |
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Posted: 4/6/2008 1:12:24 AM EDT
[#7]
If there is NOT a live round in the chamber, try banding the butt on the ground and pulling the charging handle at the same time.
Sometimes that can get you unfucked. Once I had to reef my Bushmasters bolt back with a multi-tool. |
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Posted: 4/6/2008 1:31:38 AM EDT
[#8]
I would not be surprised if you find that the KB was the result of bullet setback with the Remington ammo. I stopped using it about a year ago after finding that a few shots seemed to be a bit too hot while firing. When I removed the magazine and extracted the chambered round, I found that the bullet had substantial setback in the casing. Remington's factory crimp is inadequate for use in a semi-auto rifle. I will not use it again.
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Posted: 4/6/2008 6:32:26 AM EDT
[#9]
Dammit, I just bought two boxes of 50rd. How frequently would this type of stuff happen. Nothing but good reviews online about the UMC.
Would Rem actually give out info about bad batches? |
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Posted: 4/6/2008 6:57:20 AM EDT
[#10]
FYI its CMMG not CCMG
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Posted: 4/6/2008 7:00:05 AM EDT
[#11]
+1 If it was ammo related, the manufacturer of the ammo owes you a new rifle. |
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Posted: 4/6/2008 7:05:37 AM EDT
[#12]
like this:  |
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Posted: 4/6/2008 7:10:41 AM EDT
[#13]
Non lined should be fine as long as its a 5.56 chamber.That ammo has had problems before and bullet set back can cause higher pressure for sure..as well as 5.56 ammo in a match chamber but I beleive unlined or lined all the bargain bin rifles have 5.56 chambers.
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Posted: 4/6/2008 7:50:19 AM EDT
[#14]
sounds like a bullet set-back/overpressure issue, the extracter is probably bent back and jamming in the bolt closed
try the smacking the stock on the ground clearing method, if not, you may need to start using tools(brass drift on the carrier) |
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Posted: 4/6/2008 8:06:03 AM EDT
[#15]
We've had alot of problems with standard Remington .223 pushing back into the casing.
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Posted: 4/6/2008 8:17:17 AM EDT
[#16]
Wow, the sucks. Glad no one got hurt. I have a few hundred rounds of UMC that I'm going to run through my Lee crimp die before I shoot them. Can't hurt and could save me and my gun.
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Posted: 4/6/2008 11:31:29 AM EDT
[#17]
Anybody know the length it should be so I can Mic the ones I have now? Should I just compair it to the BlackHills ammo I have?
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Posted: 4/6/2008 11:43:43 AM EDT
[#18]
UMC is 2.215" ZM |
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Posted: 4/6/2008 11:52:39 AM EDT
[#19]
Glad you got it apart and good luck with getting it replaced.
I am surprised to hear the bad info on UMC. I have put thousands of rounds of UMC through my ARs with no problems other than one round that didn't have a primer hole. |
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Posted: 4/6/2008 12:45:18 PM EDT
[#20]
tag
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Posted: 4/6/2008 12:50:46 PM EDT
[#21]
Sounds like an ammunition issue, which comes up on the boards a couple times a year. Some people get worked up and convinced its the weapon, but it almost never shakes out to be the cause. Contact the ammo company and email them pictures of everything.
Looks like the weapon held up pretty well. |
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Posted: 4/6/2008 4:25:03 PM EDT
[#22]
Looks like the results of using pistol powder in a reload. The magazine did its job, and you should be happy that the pressure blew out of it rather than blow your upper into your face/left arm!!
The powder burned to fast bolt didn't have time to unlock (check the bolt teeth they may have indentions showing this) as the round had backpressure, all of the pressure had to go somewhere so your shell casing pressed against the chamber wall, the primer failed and pressure released out the casing. The torn part of your shell casing is from the final removal of the shell rather than the actuall accident that caused this. I know because It happened to 2 of my rifles. 1st one I counted off as being a extractor problem or other problem with the rifle. Then when the 2nd one blew it took the complete upper and welded/annealed the brass inside of the chamber so no inspection of that could be done. But I was able to dig out the piece of the upper that dug into my arm from it happening. And made the shop owner who loaded the rounds up(supposidly his buddy who had been doing it for years) pay for 2 uppers and bolt carriers that were split as well, You might want to check yours out!! I'd pull the bullets out and check as well, what gave it away for me was 2 kinds of powder when I pulled it a small stick shape and even smaller disks. |
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Posted: 4/6/2008 5:26:30 PM EDT
[#23]
List of things that can destroy a PMAG:
Uparmoured M915 Actual impact at close range from high powered rifle bullets Case head failure/KB Every time I read about a KB (that isnt a M2 .50, which is almost always caused by too much head space or timing advance) it is always Remington ammo. every time. uppers vary, it can happen to DI or piston uppers. The ammo is ALWAYS Remington. Once I was shooting a .22 with remington ammo and a round sounded a little "off" and I was about to shoot again and the alarm in my head said "STOP!...something is wrong...rod the bore!" The bullet had disintegrated and pieces were left in the bore, big enough the next round would have been very messy. I think Remington should replace all your shit and I think they owe a lot of upper makers, and Glock, an apology (the last one I remember was a POF), not to mention some serious paper. Something is obviously wrong with thier fucking brass. |
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Posted: 4/6/2008 5:46:53 PM EDT
[#24]
Wolf ammo claims another victim!
O wate... |
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Posted: 4/6/2008 6:13:21 PM EDT
[#25]
UMC & Ultramax have caused more KBs than any other ammunition, from what I've seen here on ARFCOM....never had one myself. Saw one at Ft. Campbell once, blew the carrier apart so bad that the upper lost it's whole right side. The lower ballooned the mag well noticeably, and the shooter needed stitches to fix the fragment wounds to his face. The weapon was a complete loss, and the shooter got a case of perma-flinch.
It wasn't the weapon, it was the ammo. Have things checked out before firing again, the overpressure may have fractured the barrel, extension, bolt, carrier, and/or receivers. Continued use could result in a catastrophic failure later, costing you much more than a Pmag. Sorry for your incident, glad no one was hurt. Hope all is still well with your CMMG. |
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Posted: 4/6/2008 6:23:19 PM EDT
[#26]
tag-a-roo
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Posted: 4/6/2008 6:25:29 PM EDT
[#27]
Remington ammo and Smith & Wesson (for everything but their revolvers) have been crap for years, but it's like no-one pays any attention. Americans are big - too big - on old brand recognition, and not smart enough to wise up sooner. Ever see those "Smith & Wesson" bicycles they try to market to police forces? Crap bikes for the money, but hey - it has S&W's name on it, so there are people who choose to buy it. Fools and their money... |
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Posted: 4/6/2008 10:03:01 PM EDT
[#28]
Glad there were no injuries. Sorry to hear about the KB. I'd be inclined to guess it's ammo related as well. Were these reloads or factory? Sorry if I missed that detail. Hard to tell for sure, but one of the shots showing the primer looks like it's flattened a fair amount which would of course indicate abnormaly high chamber pressure.
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Posted: 4/6/2008 10:06:29 PM EDT
[#29]
factory
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Posted: 4/6/2008 10:08:26 PM EDT
[#30]
i'd say that the failure was due to an ammunition problem.
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Posted: 4/6/2008 10:10:46 PM EDT
[#31]
Thanks for the info on the ammo! Well, that certainly doesnt give me a warm fuzzy about my UMC
I'll be keeping a close eye on that stash! Best of luck with the CMMG people and or Rem. Keep us updated.
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Posted: 4/6/2008 10:30:33 PM EDT
[#32]
Your first paragraph makes it sound as if you feel it is the PMAG's fault. You're lucky it blew out the window in the mag. I've seen case failures such as this with a metal and an aluminum mag. The results are much worse for the shooter.
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Posted: 4/7/2008 2:52:08 AM EDT
[#33]
Well, I mic'd all 100rds last night. 60 were right at or just a TINY bit under the 2.215.
32 were at 2.218. 8 were at 2.222. So how much is out of spec? Would the 2.222 or 2.218 be likely to fail? |
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Posted: 4/7/2008 4:29:06 AM EDT
[#34]
I have had that happen to me twice since 1979.
Both times it ruined the mag and that is all. The cartridges were bulk stuff purchased at a gunshow in an ammo can, mixed headstamps. I was only plinking away and so I was not concerned about quality ammo back then. So what you have there is a testament to the durability of the rifle, and the absolute proof of what can happen with shit ammo. Another fine reason to not hold a rifle by it's mag. |
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Posted: 4/7/2008 4:43:33 AM EDT
[#35]
.... it can also bow out your lower from the pressure. be sure and check to see if the mag opening is not widened. no one stated that it could also be an out of battery discharge unless you are sure the bolt was locked up.
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Posted: 4/7/2008 4:58:00 AM EDT
[#36]
The bullet set back would show after the round was stripped from the mag and loaded into the chamber. When the bullet hits the feed ramp, if not properly crimped, the bullet will get pushed back a little causing over pressure. Glad you are alright. FB |
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Posted: 4/7/2008 5:50:20 AM EDT
[#37]
How did you get the bolt back?
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Posted: 4/7/2008 5:56:31 AM EDT
[#38]
Glad you're alright, could have been much worse.
When bad ammo attacks.    
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Posted: 4/7/2008 6:01:00 AM EDT
[#39]
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Posted: 4/7/2008 6:45:03 AM EDT
[#40]
Alright, so do I cycle the 100rds through the rifle and spec them afterwards? |
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Posted: 4/7/2008 6:51:10 AM EDT
[#41]
LUVPILOT, fist off, GLAD YOUR AND YOUR FRIEND ARE OK!!!
I just wanted to post saying that last night I TOO took my BARGAIN BIN and PMAGS to Red's Range here in South Austin.. I was by myself, and first time shooting this rifle, so I was a little nervous to say the least. My lower is Double-Star, but I have the same upper and probably same unmarked barrel, DPMS stock, etc.. I put 50 rounds through it no problem. This was using the same magazine TWICE IN A ROW, first time 30 rounds of I.M.G 5.56, and the second time 20 rounds of SME Malaysian 5.56 Ball M193. It shot flawless, which is good cuz I was kind of skeered being all by myself and this being my first time. I inspected my M4 feedramps, Mag top, and inside the chamber (not field stripping, just looking in) after each mag to see if there was wear, where it was, was there a lot of brass or copper inside there, etc.. I also checked to make sure my bolt was closing after all 50 rounds. I also tried not to rest the rifle on the mag - using my VFG for stability (standing position). It was pretty hot when I was done, and put it away. I got home and it was still slightly warm, but it all looks OK inside. The only thing I noticed is I hear some rattling around from where the buffer comes into the upper receiver area. Like something is rolling around loose inside - I haven't yet stripped it down to inspect, but will post up when I do. In any event, I wanted to share my story in case it gives you more data points for you to figure out what happened on your end. Regards, Kevin |
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Posted: 4/7/2008 9:03:07 AM EDT
[#42]
The Magpul is probably the reason the gun and the shooter are still intact. It did exactly what it was supposed to do. I think the gun did a hell of a job containing the KB. I sent e-mails to both CMMG and Rem yesterday. I don't, at this point, feel the gun was the issue. |
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Posted: 4/7/2008 9:04:36 AM EDT
[#43]
WOW 
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Posted: 4/7/2008 9:12:14 AM EDT
[#44]
Are you kidding me? the M&P rifles are great...the M&P pistols are getting rave reviews (although not my cup of tea) the standard pistol line is still being used by police across the US. Are you basing you beliefs on reality or a preconceived notion? are you thinking about the old European owned S&W?? |
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Posted: 4/7/2008 10:40:46 AM EDT
[#45]
Overall length of the loaded round can be important but IMO a minimal amount of setback will not drive pressures this high. What is more imporant IMO is the complete cartridge dimensions. In particular the length from the case head to the shoulder. This what set the headspace. This is really impossible to measure with calipers. Order one of these and check the loaded rounds that you still have. Case Length Gauge from Midway From Midway:
ETA: If your ammo checks out as being 'in spec' then consider a set of Go, No-Go Gauges to check that the chamber is in spec and doesn't have excess or not enough headspace. |
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Posted: 4/7/2008 3:01:48 PM EDT
[#46]
+1 
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Posted: 4/8/2008 3:50:22 PM EDT
[#47]
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Posted: 4/8/2008 4:09:26 PM EDT
[#48]
I hope nobody got hurt there. |
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Posted: 4/8/2008 4:17:16 PM EDT
[#49]
Surf the Ammo forum.... |
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Posted: 4/8/2008 4:25:57 PM EDT
[#50]
I had a Colt SP-1 do this about 15 years ago. I don't remember what ammo I was shooting.
Anyway, it turned out that that particular rifle had excessive head space. |
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