View Full Version : Another Kaboom from Arfcom
http://www.ar15.com/forums/topic.html?b=3&f=118&t=534856&page=1
With the few kb's and suspect ammo threads that have been going around I thought I'd add to the pile.
It doesn't seem clear as to what the actual cause was yet, but its worth keeping eye on.
http://www.ar15.com/forums/topic.html?b=3&f=118&t=534856&page=1
With the few kb's and suspect ammo threads that been going around I thought I'd add to the pile.
It doesn't seem clear as to what the actual cause was yet, but its worth keeping eye on.
It most likely wasn't an ammo issue, but a build quality issue.
C4
ForTehNguyen
04-21-11, 22:08
possible barrel obstruction? It blew the gas rings and the bottom of the BCG where all the gas impinges. Wheres the cam pin at
Does Double Star even use 5.56 chambers, or do they use .223 like other lower tier rifles? Not the cause, but probably didn't help with the overpressure.
I like how the guys says that doublestar is great because they are going to fix it and send a new one. Maybe I would look else were for a new gun, but then again it was the guys fault the gun blew up not the gun ( mostly likely).
possible barrel obstruction? It blew the gas rings and the bottom of the BCG where all the gas impinges. Wheres the cam pin at
Agree with possible barrel obstruction, reloading issue, projectile compressed back into the case...Pressure way to high.
The cam pin is still in the bolt. You can see the bottom of it in the photos. Some of the photo angles/lighting make it appear as if the pin is missing.
devildogljb
04-22-11, 01:58
I'm going with quality of the upper. And who the hell is double star never even heard of the damn company.
wetidlerjr
04-22-11, 02:23
I'm going with quality of the upper. And who the hell is double star never even heard of the damn company.
They have been around for awhile They also make a 1911.
DoubleStar (http://www.star15.com/)
DoubleStar search on m4carbine.net (https://www.m4carbine.net/gtsearch.php?cx=003496919632624929056%3Adhiwgm0hbaa&cof=FORID%3A10&ie=UTF-8&q=DoubleStar&siteurl=www.m4carbine.net%2Fforum.php)
No, I don't own any of their rifles or pistols.
Magic_Salad0892
04-22-11, 03:38
Ever notice that you always here about catastrophic phailures, ''kabooms'' and other crap on TOS, but you almost ever hear about a dude's Colt LE6940 blow up here.
Makes you wonder.
wetidlerjr
04-22-11, 03:57
Ever notice that you always here about catastrophic phailures, ''kabooms'' and other crap on TOS, but you almost ever hear about a dude's Colt LE6940 blow up here.
Makes you wonder.
Yes, most strange. :cool:
Ever notice that you always here about catastrophic phailures, ''kabooms'' and other crap on TOS, but you almost ever hear about a dude's Colt LE6940 blow up here.
Makes you wonder.
Oliver Stone told me there is a conspiracy to cover up all the Colt, BCM, Daniels, and Noveske failures, so we can preserve our illusions of quality. I'm sure he's right. After all, he says that even though he hates guns, if he owned one, it would be just as good as a Colt.
:rolleyes:
Robb Jensen
04-22-11, 07:07
Ever notice that you always here about catastrophic phailures, ''kabooms'' and other crap on TOS, but you almost ever hear about a dude's Colt LE6940 blow up here.
Makes you wonder.
Colts can blow up too but most of the time it's ammo related. I believe it was Pat Rogers that had a LE6940 blow up either last year or the year before in class. IIRC Colt replaced it and I can't remember what caused it.
I have a Doublestar M4gery that that I bought used for good price during the hysteria. It has a couple to a few thousand rounds through it with out issue. But then, I put a BCM BCG in it and shelved the original.
Regardless of upper brand, that was a lot of pressure, to cause that. Its either from a barrel obstruction, pistol powder in the case, or possibly the bullet shoved ALL the way back into the case, and loose past the neck, upon chambering. Look at the pressure that caused the sides of the upper to bulge and break, the extractor looks peeled back as seen in most over pressure failures, and it looks like the bolt, on its way back, was forced downward, with the blast that sought the easiest way out (through the magwell), and the downward forced bolt broke out the bottom of the carrier. This is not simply a case of a faulty carrier. It looks like you can see part of the mangled, case, with no base, still in the chamber.
While I don't own a single thing made by doublestar, and never will, Colts blow up too. I saw pictures of a 6920 that was in use in a training class, using XM193, that looked very similar to this doublestar, only it had way more damage. The left side of the upper was completely blown out the side, and the bolt was almost unrecognizeable. Any gun will blow when you have an over pressure situation like that.
Glad no one got hurt. Rifles can be replaced.
I'd like someone who thinks it is the rifle to explain how/what part of the rifle failed and caused the KB.
The chamber pressure was too high and here is the simple evidence:
Pic #2 shows the case with typical high pressure failure where the brass flowed under the extractor.
Pics #2 and #3 show brass colored vapor deposits on the side of the bolt. Brass does not turn into a liquid at normal chamber pressures.
A bore obstruction would have to be close to the chamber to cause that much pressure.
The chamber pressure was too high
Same thing happens when a Glock Kabizzles.... :eek:
Gee a gun blows up when the chamber pressure is over 70k!!! OMG!! :p
ForTehNguyen
04-22-11, 09:40
did this thing fire out of battery? If it was high pressure wouldnt there be more damage to the barrel extension and bolt face/lugs?
did this thing fire out of battery? If it was high pressure wouldnt there be more damage to the barrel extension and bolt face/lugs?
No, the design of the AR does not allow the firing pin to contact the primer until the bolt is locked. OBD would not produce as much damage because the pressure is not as high.
The lugs do not fail in an AR KB. You have to think about this as a liquid escaping and flowing out the easiest path, not an explosion where the shock wave causes the damage.
Doc Safari
04-22-11, 10:43
While I don't own a single thing made by doublestar, and never will, Colts blow up too. I saw pictures of a 6920 that was in use in a training class, using XM193...
What was the issue with that ammo, do you remember?
BTW I decided against a Doublestar when Larry Vickers used it for his mud/sand/water torture tests on his TV show. He wouldn't treat his Daniel Defense M4 like that, but instead let the Doublestar take the beating!
Does anyone have anything substantive in support of the idea that this was a rifle issue? Or are we just just using this thread to dogpile his low grade DS?
I'm also incredibly skeptical of some of his claims. So, the gun is bone dry, but that's not because it wasn't lubed, but because he wiped the oil off? Sorry, but even wiping away oil won't completely strip it from the metal like that.
It's also strange how so many failures are a "friend's" rifle or a "relative's" rifle.
A local department in my state recently had a 4-year old S&W M&P-15 blow up in a similar fashion, giving one officer a nasty hand injury. No obstructions in the barrel, Smith says the likely culprit was a double-charge in their Federal ammo. Federal has issued a recall for .45 ammo recently, but are mum on this issue so far. My department decided to pull all our fed ammo from our patrol rifles an replace it with Winchester, even though it is a different lot number.
I'd like someone who thinks it is the rifle to explain how/what part of the rifle failed and caused the KB.
The chamber pressure was too high and here is the simple evidence:
Pic #2 shows the case with typical high pressure failure where the brass flowed under the extractor.
Pics #2 and #3 show brass colored vapor deposits on the side of the bolt. Brass does not turn into a liquid at normal chamber pressures.
A bore obstruction would have to be close to the chamber to cause that much pressure.
I did not look at the all the pics so it is possible you are right. Headspacing was my first answer.
C4
A local department in my state recently had a 4-year old S&W M&P-15 blow up in a similar fashion, giving one officer a nasty hand injury. No obstructions in the barrel, Smith says the likely culprit was a double-charge in their Federal ammo. Federal has issued a recall for .45 ammo recently, but are mum on this issue so far. My department decided to pull all our fed ammo from our patrol rifles an replace it with Winchester, even though it is a different lot number.
Most rifle powders for .223/556 you CAN"T double charge it, as most standard (for .223, et al) powders dang near fill the case, or at least up to the shoulders....PISTOL powders, yeah I can see that happening, and it will most likely KABOOM, but not powders intended for .223...
Robb Jensen
04-22-11, 13:20
No, the design of the AR does not allow the firing pin to contact the primer until the bolt is locked. OBD would not produce as much damage because the pressure is not as high.
The lugs do not fail in an AR KB. You have to think about this as a liquid escaping and flowing out the easiest path, not an explosion where the shock wave causes the damage.
Could have had bullet set back....All other Kb's I've seen split the carrier up at the sides and usually grenades the bolt too. Weird that it only blew out the bottom like that which is indicative that the bolt was locked and in battery when it fired. Could have had the wrong powder.
Haven't seen it mentioned here, but the OP on TOS followed up that the ammo was PPU (Prvi Partizan).
I'd like someone who thinks it is the rifle to explain how/what part of the rifle failed and caused the KB.
The chamber pressure was too high and here is the simple evidence:
Pic #2 shows the case with typical high pressure failure where the brass flowed under the extractor.
Pics #2 and #3 show brass colored vapor deposits on the side of the bolt. Brass does not turn into a liquid at normal chamber pressures.
A bore obstruction would have to be close to the chamber to cause that much pressure.
Todd, I'm in 100% agreement with you, I had two kabooms both with Colts, one Goverment model, and one with a carbine, both back in the 80's. The pictures look the same as those did, one was traced back reloads without enough crimp on the bullet, causing the bullet to be driven down into the case, thus igniting the charge. The second was factory PMC, but the end result was the same, so either PMC didn't crimp their ammo or the bullet was shoved into the case durning feeding I don't know. My magazines in each case were blown apart from the bottom of the mag well to the bottom of the mag (it looked like a barrel that had blown up on a Looney Tunes cartoon) I'm thinking all the remaining ammo was ignited also as we never found any complete rounds only a few melted cases. There was brass residue on the remains of the bolt carrier and bolt, the face-off the bolt was gone and the barrel chamber was brass colored. The upper was severly bulged, and it was the loudest bang I ever heard. My ears rang all day even with ear plugs.
Rmplstlskn
04-22-11, 16:42
Colts can blow up too but most of the time it's ammo related. I believe it was Pat Rogers that had a LE6940 blow up either last year or the year before in class. IIRC Colt replaced it and I can't remember what caused it.
I wonder if Colt would have replaced it if one's name wasn't Pat Rogers, but rather John Q. Public?
Rmpl
I have worked on two Colt ARs that "kaboomed." Same owner, same day, same batch of his reloads. Almost occurred simultaineously as father and son were on line shooting at the same time.
They only bulged the upper receiver on the left side and blew the magazine out.
the best part is no one TOS mentioned that it may be the rifle quality...
thank got for this site and the knowledge is holds, otherwise I would be screwed!
DirectDrive
04-22-11, 19:55
I'd like someone who thinks it is the rifle to explain how/what part of the rifle failed and caused the KB.
The chamber pressure was too high and here is the simple evidence:
Pic #2 shows the case with typical high pressure failure where the brass flowed under the extractor.
Pics #2 and #3 show brass colored vapor deposits on the side of the bolt. Brass does not turn into a liquid at normal chamber pressures.
A bore obstruction would have to be close to the chamber to cause that much pressure.
Supposedly it was his first shot of the session.
One thing that sticks out to me is the failed ring and the direction it was pushed.
But then I don't know if it was tampered with prior to the photo and I'm not sure about the credibility of the "reporter" to even make a guess at the cause.
You can't double charge a 5.56 case if you are using the correct powder. The second dump would spill out of the case mouth.
Using one of the hotter, correct powders you could over charge a 5.56 and run pressures into the red zone.
the best part is no one TOS mentioned that it may be the rifle quality...
I do not believe the Kaboom was caused by the rifles quality. Once the Kaboom occurred the quality of the rifle may have had something to do with the amount of damage that was caused. Regardless of the rifle's quality it would have sustained severe damage under the pressure that caused that.
the best part is no one TOS mentioned that it may be the rifle quality...
thank got for this site and the knowledge is holds, otherwise I would be screwed!
Why is that "the best part"? If you have been reading this thread, the folks that know what they are talking about, know that the "quality" or manufacturer, probably has NO bearing on this type of failure.
Why is that "the best part"? If you have been reading this thread, the folks that know what they are talking about, know that the "quality" or manufacturer, has NO bearing on this type of failure.
Lot's of unsubstantiated conjecture about DS in earlier posts... When my son wanted to build a budge m4gery I researched DS quite a bit. For the record:
- DoubleStar uses a true 5.56 chamber
- Can be had with 4150 1:7 chromed barrel, etc. Default is a 4140 with chrome lined as an option. Shaw mfg'd, except the 4150 ones appear to be contract of some form. The FL company with the GI parts contract in Daytona???
- Lowers are forged 7075 from the same mfg who makes some of the big names (CMMG? CMT?). (yes, I know the lower is immaterial here)
- Based on the first chart, it actually did pretty well. Including park under FSB, etc. F marked fsb.
- We did not upgrade the BCG, so it's a semi without MPI bolt. But we could have upgraded if budget allowed.
- FCG was decent, better than most clones, but not as clean/crisp as DD/LMT
His is pushing 1k rounds at this point, and has been pretty much flawless. (Yes, he's a fun shooter. He'll get his Colt/FN experience at USMA this June). I'm aware of roughly a dozen DS's friends built, with similar results.
Not to say they are good, or M4C "worthy"..... just that I don't believe for an instant that this kaboom was due to DS. Too many signs point to high pressure. I'd bet barrel obstruction.
No connection to Doublestar, just a satisfied user. It is what it is: a decent budget blaster. I'd buy one in a heartbeat over a Bushy, etc. My last purchase? LMT complete lower, so you know where my priorities are! :)
Silver_2325
04-28-11, 00:58
Pretty obvious from the white bolt that that gun has not been properly maintained and oiled.
I noticed a few things looking at the pictures....the weapon was not properly lubed/maintained. Also if you look at picture #2 you can see some of the casing in the chamber. This looks as though there's a barrel obstruction of some kind. You can see the powder burns on the bolt....this reminds me of the COLT M4's that went boom on our firing line. Some were caused by human error, i.e. "I forgot the cleaning rod was still in there!" or a squib round & someone didn't notice it so they fired again. In either event I have seen them where the bolt is in the chamber in the "locked" position after the explosion & I have seen them where the bolt is/was in the rear "unlocked" position. That's just my input but I wasn't there & looks can be deceiving!
Here's some pics of a M4 incident, I know what happened with this one, I was there.....
http://i115.photobucket.com/albums/n288/184SFS/M4%20Rifle%20Accident/IMG00007.jpg
http://i115.photobucket.com/albums/n288/184SFS/M4%20Rifle%20Accident/IMG00014.jpg
http://i115.photobucket.com/albums/n288/184SFS/M4%20Rifle%20Accident/IMG00009.jpg
http://i115.photobucket.com/albums/n288/184SFS/M4%20Rifle%20Accident/IMG00010.jpg
http://i115.photobucket.com/albums/n288/184SFS/M4%20Rifle%20Accident/IMG00008.jpg
http://i115.photobucket.com/albums/n288/184SFS/M4%20Rifle%20Accident/IMG00001.jpg
I noticed a few things looking at the pictures....the weapon was not properly lubed/maintained. Also if you look at picture #2 you can see some of the casing in the chamber. This looks as though there's a barrel obstruction of some kind. You can see the powder burns on the bolt....this reminds me of the COLT M4's that went boom on our firing line. Some were caused by human error, i.e. "I forgot the cleaning rod was still in there!" or a squib round & someone didn't notice it so they fired again. In either event I have seen them where the bolt is in the chamber in the "locked" position after the explosion & I have seen them where the bolt is/was in the rear "unlocked" position. That's just my input but I wasn't there & looks can be deceiving!
Here's some pics of a M4 incident, I know what happened with this one, I was there.....
http://i115.photobucket.com/albums/n288/184SFS/M4%20Rifle%20Accident/IMG00007.jpg
http://i115.photobucket.com/albums/n288/184SFS/M4%20Rifle%20Accident/IMG00014.jpg
http://i115.photobucket.com/albums/n288/184SFS/M4%20Rifle%20Accident/IMG00009.jpg
http://i115.photobucket.com/albums/n288/184SFS/M4%20Rifle%20Accident/IMG00010.jpg
http://i115.photobucket.com/albums/n288/184SFS/M4%20Rifle%20Accident/IMG00008.jpg
http://i115.photobucket.com/albums/n288/184SFS/M4%20Rifle%20Accident/IMG00001.jpg
Magic_Salad0892
04-28-11, 03:13
Colts can blow up too but most of the time it's ammo related. I believe it was Pat Rogers that had a LE6940 blow up either last year or the year before in class. IIRC Colt replaced it and I can't remember what caused it.
I know, I read that article actually. I was just referring to how often you hear about ARs, quality or not over there going tits up. And almost never hear about it on this board.
On TOS I've heard of waaaay more Colts, LMT, Noveske, and BCM guns having issues than you hear about on here. I was just making an observation. :p:o
It was November last year, BTW.
ETA: ALWAYS inspect your ammunition by eye, and measure it for setback before you decide to use it...
A lot of folks are bringing up bullet setback, as the possible cause for this type of failure. While that is a very good possibility, we need to realize, that the setback required to cause this kind of pressure, typically occurrs when the bullet hits the feedramp, upon chambering. This would not usually be prevented by inspecting your ammo before loading, as some are suggesting.
A minor set back does not usually produce enough pressure to cause a complete structural failure, as in this case. A setback upon going into the chamber, in which the bullet is severely pushed into the case, and to the extent of being loose, behind the neck, can cause this type of pressure spike. A setback of this nature is usually caused by the tip of the bullet getting hung up, or stopped on something, during chambering. A mismatch between the M4 feedramps of the receiver and barrel extension, in which there is an overhang by the extension, can cause a hangup of this nature. 99.9% of the time, the rounds feed high enough on the ramps, to never catch on this ledge. But, that one in a million round, that the mag doesn't push quite high enough, and combined with a round that may have a somewhat loose crimp on the bullet, and you may shove that bullet way back into the case, and a kaboom waiting to be touched off.
Folks, this is why I am anal about the match up of the M4 ramps on my guns. An overhang by the extension's ramp, over the receiver's ramp, is a no go, as far as I am concerned. Don't assume for one minute, that the top brands don't occassionally have this issue. I, have received at least three, probably four, (out of seven I have owned from that company) new uppers, from a top brand manufacturer, that had this condition. Rather than send them back, I simply disassembled the uppers, and properly blended and finished the ramps. DON'T EVEN ASK ME TO REVEAL THE COMPANY, because, no, I did not contact the manufacturer, I simply fixed them myself, which was less hassle and faster for me. I will not mention the company because I don't want my post deleted, like last time. If you think its a safety issue, then simply check your ramps no matter what brand you have, as any brand is capable of letting a few by, in QC. Some do this simple check, in a few seconds, with a straightened paper clip, to slide the tip of, up the ramps, to see if it catches where the ramps meet.
Would this condition always cause the gun to blow up? Probably never. You have to have the other conditions in place for this to be a real risk (a round fed low, and a less than tight bullet crimp, usually). But, it is a risk, and one that can be avoided by proper ramp matching.
Was this the cause of some of the KB's seen on the net? Maybe. Squibs, I think less likely, since the AR design would require the squib to land in the very last few inches of the barrel (past the gas port), to cycle that new round on top. Now, if a new round was charged manually, by the shooter, on top of a squib, that was mistakenly perceived as a failure to fire, then yes, very possible. Most KB reports that I have read, the shooter states that they were just firing normally, and don't mention running the charging handle, after a failure to fire, just prior to the KB.
Just something to think about folks, it only takes a second to check your ramps. I can't for the life of me, figure why companies don't pay closer attention to this. I can't believe how many oppers I have seen with a ramp mesh that could cause a hangup. I take it seriously.
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