Hi All.  I came accross this thread on another forum (GlockTalk) that I also frequent.  After others to include myself believed we had worked through the problems the owner of the rifle in question experienced, I wanted to post a link to it here so that our new AR-15 building forum-mates would see this and perhaps avoid similar problems.  Also, if any of the more experienced members here want to solicit advice to this lucky guy who walked away after injuring only his pride, I'm sure he would appreciate any of your comments as well (especially if you live near the PA area).

Here's a photo teaser:

Here's the link: (click here)


 

I would have to say that he is DAMN lucky! Personally, unless the company (which he never said where he got it from) gaurenteed it to be "ready to run", I dont think they should have to replace anything. Was it shitty on the part of the company to let something like that go? Absolutely, but it is the ultimate responsibility of the owner to make sure that all parts are there. Hell, for free you can look around here and find dis and ass pictures and diagrams/schematics to verify things if you arent sure. For something more physical,$10 and they can get the USMC armorers manual.The first clue should have been the 2 big threaded holes in the top of his carrier with nothing in them.
I know everybody has to start out somewhere, but this is what can happen to amateurs when they try to save money or just "slap things together" without doing there research.
Is this mean or rude yes but for Pete's sake, be careful people. As for anything to add to figure this out....I think that has already been covered in the other forum.

live and learn! live and learn

That's why I am VERY leary of people here who are proud of their WECSOG gunsmithing skills, especially some of the crazy stuff I've seen on this forum.  One that comes to mind immediately was the guy who said he used a pipe wrench to help him take the barrel of his upper.  Using a pipe wrench on a barrel was bad enough, but others here congratulating him on his effort - SCARY - could have been a troll post though.  Another was the guy who drilled his 80% lower buffer tube hole off center and to correct this he started to grind his bolt carrier so that it would slide unhindered into the buffer tube.  This wasn't a troll post, this guy had pics too.  This one was receiving praise for his ingenuity as well.

All very scary, IMO.

Quoted: I would have to say that he is DAMN lucky! Personally, unless the company (which he never said where he got it from) gaurenteed it to be "ready to run", I dont think they should have to replace anything. Was it shitty on the part of the company to let something like that go? Absolutely, but it is the ultimate responsibility of the owner to make sure that all parts are there. Hell, for free you can look around here and find dis and ass pictures and diagrams/schematics to verify things if you arent sure. For something more physical,$10 and they can get the USMC armorers manual.The first clue should have been the 2 big threaded holes in the top of his carrier with nothing in them. I know everybody has to start out somewhere, but this is what can happen to amateurs when they try to save money or just "slap things together" without doing there research. Is this mean or rude yes but for Pete's sake, be careful people. As for anything to add to figure this out....I think that has already been covered in the other forum.

I gotta say that this is a bunch of BS.  It was advertised and sold as a "complete upper."  You're supposed to be able to just slap on a complete upper and fire away.  That's part of what you're paying for when you get it complete rather than as a kit.  What we have here is a breach of warranty and a manufacturing devect.  The seller's and/or manufacturer is responsible for making it right.

Quoted: That's why I am VERY leary of people here who are proud of their WECSOG gunsmithing skills, especially some of the crazy stuff I've seen on this forum.  One that comes to mind immediately was the guy who said he used a pipe wrench to help him take the barrel of his upper.  Using a pipe wrench on a barrel was bad enough, but others here congratulating him on his effort - SCARY - could have been a troll post though.  Another was the guy who drilled his 80% lower buffer tube hole off center and to correct this he started to grind his bolt carrier so that it would slide unhindered into the buffer tube.  This wasn't a troll post, this guy had pics too.  This one was receiving praise for his ingenuity as well. All very scary, IMO.

I'm the guy who used a wrench on the barrel.  The rifle is re-assembled using the same method and everything works 100%.

I did not read the other post on Grock Talk, not sure if they mentioned it there, but from the picture what happened is the shooter fired the gun without a gas key on it?

The missing gas key will allow the bolt to go forward into the barrel extension, but as it tries to turn and lock, the bolt carrier turn instead and the rifle becomes a "blow back" rifle... but only for one time.

Well, I never said that my opinion would be popular and who knows, they may replace it but you should have at least some familiarity (considering he is a member)with what you have, especially before firing it. Before you fire you should clean it anyhow, so he should of at least had the opportunity to notice that something may be amiss.
However John, I realize that companies should have their products ready for the lowest common denominator and it should have never left like that, as I had stated in my original post. He should just be prepared, especially if they have really crappy customer service to fight the place and possibly have an attorney handy if they really give him the cold shoulder. I'm curious where he got it from. He was asked several times in the other forum where he got it from and he didnt say. Now, who knows, maybe he is keeping his mouth shut to see if the place will make things better but he could have at least said something, he seemed to ignore the inquiry. On the other hand maybe he got a compete kit and got a little adventurous, meaning that he asked for an unassembled upper to put together himself. It is possible that he would have said that it was complete so that people could put the blame on the company and not him-which would only kick him when he is down after this incident happened in the first place.
I just think that this is BS that this even happened in the first place.

Quoted: I did not read the other post on Grock Talk, not sure if they mentioned it there, but from the picture what happened is the shooter fired the gun without a gas key on it? The missing gas key will allow the bolt to go forward into the barrel extension, but as it tries to turn and lock, the bolt carrier turn instead and the rifle becomes a "blow back" rifle... but only for one time.

yep.  That's what happened.

I just read through this thread and have a couple of thoughts that are more on topic:

The individual should either have had a "working knowledge" of the weapon before building it, or have taken it to a 'smith before the range... I know I would have not charged a thing to field strip it and take a look at things for a customer on the way to the range.

The company that sold the upper is liable, if it was sold as a complete upper... In fact, it is not out of the question to think that a company would fire 3 test rounds through it before shipping.

Bottom line, the owner was naive... but the company that sold the upper was irresponsable, had they never met, there would be no such problem -- but one of them has to assume that such a meeting will one day take place.

Gunzilla,
You bring up a very good point about the test firing. I didnt even think of that. Off the top of my head, most places I can think of say that they test fire the uppers prior to sale. That would very much place the responsiblity onto whoever manufactured the upper.
With that being said though, I still think the owner was rather naive to not to have a working knowledge of his weapon and that this should not have happened.
The best way to handle this may be to call the place and ask it all of there uppers are test fired before being made ready for sale or shipping. If they say "yes"then I think that would be cause for the start of a big ass chewing to whoever runs things there.

the company that sold the upper was irresponsable, had they never met, there would be no such problem -- but one of them has to assume that such a meeting will one day take place.

I couldnt have summed it up any better than that

Quoted: Gunzilla, You bring up a very good point about the test firing. I didnt even think of that. Off the top of my head, most places I can think of say that they test fire the uppers prior to sale. That would very much place the responsiblity onto whoever manufactured the upper. With that being said though, I still think the owner was rather naive to not to have a working knowledge of his weapon and that this should not have happened. The best way to handle this may be to call the place and ask it all of there uppers are test fired before being made ready for sale or shipping. If they say "yes"then I think that would be cause for the start of a big ass chewing to whoever runs things there.

test firing is sort of a given with many builders, I make a point of it... test targets are a joke, I have stood in a shop (who shall remain nameless) and watched a guy set a stack of targets on a trap, cover them with saran wrap (to prevent powder burns) then take a 10/22 and pop three rounds through them from about a foot and a half away... then they wrote in the serial numbers of the ARs they were building and put a nice "test target" in each box...

yes, the guy was naive... he trusted the seller to offset his lack of knowledge, but hey, they call these things accedents for a reason -- it was an accident that he chose that seller, let both of their mistakes serve as a warning to other?

I would certainly hope so.

I'd like to see the inside of his upper receiver after the carrier rotated like that. I hope it isn't too mangled.

I'm not sure about the upper, but I'm also really curious about the barrel and how the out of battery ignition (of course I'm assuming this because of the cleanly cut off base of the brass) affected it. Did it tear up the throat, etc?

Quoted: Quoted: That's why I am VERY leary of people here who are proud of their WECSOG gunsmithing skills, especially some of the crazy stuff I've seen on this forum.  One that comes to mind immediately was the guy who said he used a pipe wrench to help him take the barrel of his upper.  Using a pipe wrench on a barrel was bad enough, but others here congratulating him on his effort - SCARY - could have been a troll post though.  Another was the guy who drilled his 80% lower buffer tube hole off center and to correct this he started to grind his bolt carrier so that it would slide unhindered into the buffer tube.  This wasn't a troll post, this guy had pics too.  This one was receiving praise for his ingenuity as well. All very scary, IMO. I'm the guy who used a wrench on the barrel.  The rifle is re-assembled using the same method and everything works 100%.

I'm very happy for you.  As you can see, either not being familiar with what you have in your hands, or in many of the cases I've seen, not doing the maintenance with the proper tools, parts and expertise, can result in very similiar KABOOMS.  An equal number are improper bullet load related, though.  I stand firm on my opinion that AR building and maintenance is best left to those who have the knowledge AND the proper tools to do the job.

Quoted: The company that sold the upper is liable, if it was sold as a complete upper... In fact, it is not out of the question to think that a company would fire 3 test rounds through it before shipping.

Before everyone wants to crucify the manufacturer regarding whether the upper was test fired or not....

At last year's SAR Show I talked with a "well-known" AR parts vendor and asked about test-firing.  He said they don't test every upper.  Instead they spot-check a few, but for the most part every upper they assemble is similar (based on barrel length for gas port size, etc.) so test-firing each one was not necessary.  I'm para-phrasing here, but you see the point.  I bought a 10" upper anyway from this maker and it has run 100%.

Now even if the upper used by this person was test-fired, so what?  My guess is that they treated the bolt carrier assembly as a separate item and only test-fired the upper receiver/barrel assembly.  When that was done, they moved it down the assembly line to some gorilla who grabbed the bolt carrier pieces (firing pin, gas rings, etc) and brain farted about screwing on the carrier key.  He just quickly put the carrier together, put on a charging handle, slipped in the carrier and called it done.  At least that's my guess as to what happened.

Wait a minute! Doesn't the charging handle use the gas key to pull the carrier back? If I recall correctly, then it had to have at least had the key "installed" to some extent. I have found that several companys don't tighten the screws on the key down adequitly. I had that prob on my CAR a few years back first time out, and another guy on here had the same prob with an AR pistol in the last week. My new policy is to retighten those screws on any kit I get!

Quoted: The missing gas key will allow the bolt to go forward into the barrel extension, but as it tries to turn and lock, the bolt carrier turn instead and the rifle becomes a "blow back" rifle... but only for one time.

Wouldn't the charging handle meet the "flat" on the top front of the bolt carrier and prevent any rotation?

In any case, this rifle is a trifecta of bad mojo - el cheapo stock, remanufactured Ultramax ammo, and no carrier key.

Quoted: Quoted: The missing gas key will allow the bolt to go forward into the barrel extension, but as it tries to turn and lock, the bolt carrier turn instead and the rifle becomes a "blow back" rifle... but only for one time. Wouldn't the charging handle meet the "flat" on the top front of the bolt carrier and prevent any rotation? In any case, this rifle is a trifecta of bad mojo - el cheapo stock, remanufactured Ultramax ammo, and no carrier key.

I doubt enough to stop what happened... we are talking only a few degrees of rotation to be not fully locked...

People always get mad at me for discouraging new guys from building their own POS.  

Hey guys....  Lots of good comments here.  I posted this so that others who are less experienced than most of you will hopefully use a little more caution and prudence.  As I said earlier, I am glad this guy is OK and I am also glad that he posted his experience (even though he most likely knew that in doing so, he opened himself to a (deserved) bruising of his ego).  

Anyway, if this post helps at least one newbie ot double/triple-check his new gear before firing and/or have another more knowledgable friend help him/her out....then I will consider my "mission" accomplished.    

Quoted: The missing gas key will allow the bolt to go forward into the barrel extension, but as it tries to turn and lock, the bolt carrier turn instead and the rifle becomes a "blow back" rifle... but only for one time.

The bolt carrier won't turn, even without the gas key, the bottom edges are flat and rest on the lower edges of the sides of the inside of the upper receiver.

That said, I wonder if he had any trouble pulling the charging handle back... With the bolt and carrier properly seated, the charging handle will still hit the edge of the cam pin, BUT pulling on the cam pin is like pulling on the bolt, and if the bolt was locked, it probably would've been a pretty hard handle to pull.

I was ignorant when I got my first AR15, I learned by owning, shooting, and cleaning it. I can't blame the guy for getting the upper and lower separately, who here doesn't want to save money? It's a reasonable expectation to be able to just put the upper and lower together and go.

Quoted: People always get mad at me for discouraging new guys from building their own POS.  hr

Do you really consider putting a 'complete' upper on a lower as building a rifle?

If this guy was actually building the rifle from scratch he would probably know what a gas key was and would have installed it.

Sounds like a few people need to take some time and study their rifles...

Look at what the charging handle engages... it is not the cam pin or any of that.

See that the bolt will turn... and look at how little it has to turn to not lock up properly.

There are no tracks or whatever that the bolt rides on... the specs call for a round hole, round is round... and the bolt key is called the bolt key for a reason.

Quoted: Sounds like a few people need to take some time and study their rifles... Look at what the charging handle engages... it is not the cam pin or any of that. There are no tracks or whatever that the bolt rides on... the specs call for a round hole, round is round... and the bolt key is called the bolt key for a reason.

without the key, it looks like the charging handle will hit the cam pin, but about the carrier, yeah my mistake, it looked like there were rails, but i was just distracted by the grooves in the carrier that let it clear the edges of the magazine.

Well maybe I'm one of the idiots, but I'm getting ready to partially build my own for the first time. I will be buying a complete kit and stripped lower. I've been reading everything I can find here to prepare for it and this was certainly valueable because I didn't even know about a "gas key" before. How would anybody ever learn to build one if they never start?

I think I will at least take it to a pro to look at after I build it just in case something is wrong.

Quoted: ...Anyway, if this post helps at least one newbie ot double/triple-check his new gear before firing and/or have another more knowledgable friend help him/her out....then I will consider my "mission" accomplished.

Quoted: ...I'm getting ready to partially build my own for the first time. *snip* ...this was certainly valueable because I didn't even know about a "gas key" before. How would anybody ever learn to build one if they never start?  I think I will at least take it to a pro to look at after I build it just in case something is wrong.

"Mission Accomplished"  

Rigor asked:



quote:
--------------------------------------------------------------------------------
Where's the gas key on your bolt carrier?
--------------------------------------------------------------------------------



Looking at the picture, I think Creeper that the key was not installed to start. It woud be VERY hard for the key to come off if it were installed. If it weren't fully screwed down (two allen screws on secure it to the carrier) then you would have had a hard time operating the charging handle.

I can see a lack of a gas key producing exactly what you described. The rifle would fire -- presuming you chembered the round fully -- but it would never cycle. The gas coming back into the chamber would just be blasting all around and, if you look at the side of the carrier (forward half) that is a LOT of fouling for four shots -- unless there was no gas key and the gasses were just pouring over the carrier.

Did you build the carrier/bolt asembly yourself? Did you disassemble and inspect every part of the rifle before firing?

Look, if you get it open and the key is floating around in there, well I'm wrong. But I don't see how this happened otherwise.

TO GET THE RIFLE APART: Besides what Chessman said, you might try this: The remants of the buffer tube are plastic. There's really only a small ring of it left -- there's not much room between the back of the receiver and the buffer spring detent. You could try breaking it up by inserting a thin screw driver and prying up. Or, a a SHARP chisel or craft knife, CAREFULLY diven against the back edge of the remant of the tube should go through it. Do this in a three places and the ring that's left should come out in pieces. BE CAREFUL not to damage the threads on the receiver -- it is softer than any tool you'll likely use.

Keep us posted.


__________________


tslex

"Democracy is two wolves and a lamb voting on what to have for dinner. Liberty is a well-armed lamb contesting the vote."
-Benjamin Franklin


Last edited by tslex on 09-26-2004 at 04:03 AM

Where did the stock and buffer tube come from ?
In "Rigor's" diagnosis He says the buffer tube is Plastic!
Not on any M16 or AR15 I have owned or fired have I ever had a Plastic
buffer tube.

                      Jim

Quoted: Well maybe I'm one of the idiots, but I'm getting ready to partially build my own for the first time. I will be buying a complete kit and stripped lower. I've been reading everything I can find here to prepare for it and this was certainly valueable because I didn't even know about a "gas key" before. How would anybody ever learn to build one if they never start? I think I will at least take it to a pro to look at after I build it just in case something is wrong.

89grand...

I certainly hope that you don't think I, in any way, was calling anyone an idiot or trying to dissuad anyone from "rolling the own" rifle? Not at all... in fact, there is no better way to learn than to start doing it -- There is no replacement for experience however and I certainly hope that you have someone you can turn to with questions, or at least check your work?

Not claiming at all to know what I am talking about... but I have picked up a few things along the way and hope you have fun and keep it safe!

BTW: The hook at the end of the charging handle engages the small flat "cut out" at the very end of the bolt carrier, in front of the cam pin.

Quoted: Last edited by tslex on 09-26-2004 at 04:03 AM Where did the stock and buffer tube come from ? In "Rigor's" diagnosis He says the buffer tube is Plastic! Not on any M16 or AR15 I have owned or fired have I ever had a Plastic buffer tube.                       Jim

Hi Jim.  I am "Rigor" over on GlockTalk (the mountain bike I ride is a Moots model "Rigormootis") and that comment/diagnosis was not made by me...it was made by "tslex"...

No one finds it ironic, we a linking to a KB at glocktalk?  (even though it is an AR - which is still going to be serviceable, I should point out.)


As far as test firing goes, since it was a complete upper, I probably wouldn't expect it to have been test fired.  Could they put it on a lower and fire it? Of course.

My homie Creeper actually bought all of that stuff from ************ and it's all made of quality RRA components so I highly doubt the rifle is to blame. However he did put it together himself so he might be at fault for improper assembly. Either that or the cheap shit ammo he was using.

Edit: I edited out the name of the company because it appears that most people seem to think that the company Creeper bought it from is responsible. I highly doubt that's the case. I tried to tell him to take the upper and lower to a qualified smith for assembly but he was intent on doing it himself. I spent quite a bit of money with the company he ordered the upper from, they've taken good care of me every time I've ordered something. I have no doubt if it is the company's fault that they will take care of the customer.

Hey Rigor, Sorry about that.
The only reason that I picked up on the plastic buffer tube comment is that
with the shortage of  folding/collapsable stocks brought on by the AWB sunset
People have been ordering same from airsoft/toy manufacture's.
So when I read plastic , I thought the question needed to be asked.

                                Jim

Hey no problem Jim....  I know nothing about Airsoft stuff...hell I didn't even know any of their parts were close enough in fit to even create a possibility for such a problem.  I guess it's good to post the dangers of such things for some truely noobs might get duped if they know absolutely nothing/don't know the difference....  That said, such folks shouldn't be building their own ARs.  Now...I can understand that "Creeper" wanted to do this himself...and he learned a valuable lesson in the process.  I bet he is already well along the path to learning ALOT more about his rifle than he originally planned.    

Hi everybody. Well here's the lowdown. I knew I didn't want to get the tools to build my own upper... that's why I bought one complete.  Having not seen a disassembled AR before, I frankly did not think my bolt carrier was missing anything when I looked at it.  I  wrote that part of the assembly off as "done" and focused on putting together the lower. The result is what you see in the pics on the other thread.  As MichealBeverage said, I cannot put the blame solely on the place I ordered it from... I should have checked the upper against a parts diagram and not just slapped it on my lower and headed to the range.  (Although I don't really remember him and I having the whole "you better take it to a qualified gunsmith first" conversation... but I do seem to recall a "real men put their own AR's together themselves conversation" he
Live and learn!

Quoted: I can't blame the guy for getting the upper and lower separately, who here doesn't want to save money?

Me.


As you can see, it's false economy.

This is why I always recommend a newbie buy a factory gun.

Quoted: How would anybody ever learn to build one if they never start?

Well it would help to download the damned TM and at least have a guide to follow.

Creeper1313
Check the chamber in the barrel!

I'm a bit concerned that on the Kaboom round the bullet may have jumped a gap between the chamber and the barrels bore thus using the chamber like a funnel for the bullet to make it's way down the barrel.  While the chamber  in an AR is supposed to be good to like 53,000psi the effects of a bullet jumping a gap between a chamber and the bore may have damaged the barrel too!

If I were you I'd call the company who you got the upper from and demand they send you a whole new complete upper plus a telestock for free.  Before you put the new upper on your fixed lower post a picture here on ar15.com of all your new upper parts stripped apart and the board members should notice if anything is missing like the carrier key.  Yo can look at the exploded AR15 (no pun intended) diagrams on the site (click here) to see if you have all the proper parts for the new upper.  BTW I'd mark the old upper with a black sharpee marker on the inside of the upper and on the barrel to make sure the company dosn't send you the same old parts back, cover all the bases.

For the money buy the USMC M16A2 manual click here. It's the best $6 you'll ever spend.  

Glad to hear you haven't lost faith in the AR15  And if you have any questions don't hesitate to ask.

Quoted: Quoted: I can't blame the guy for getting the upper and lower separately, who here doesn't want to save money? Me. As you can see, it's false economy. This is why I always recommend a newbie buy a factory gun. Quoted: How would anybody ever learn to build one if they never start? Well it would help to download the damned TM and at least have a guide to follow.

Well, I won't be building it for at least a few weeks. I'm getting all of the information I can get before hand. I will be asking more questions and getting it looked at by a pro before I shoot it. I'm not building the upper because I don't have the tools or knowledge to do it, I'm only building the lower. I know that's important too though. I'm not dumb enough to attempt this blindly.

Then there are idiots like me who have sat with an an AK-47 Front Trunion and Barrel assembly with the Bolt assembly and an AR-15 lower and tried to figure out how I could make the parts work together....

Very interesting story....!!!!

You would be lucky if the manufacture goes replace your parts free of cost.

Since you bought parts only,  you assumed the responsibility of  having the knowledge and tools to assemble the parts in to a weapon. And test the parts and assembly at your own risk short of parts failure.

But I have seen companies offering up parts free even when it is the customer's fault for incidents(seen a few of reload blowups that  manufactures were willing to replace parts)

Gunzilla called it.  On the fourth round, the carrier turned instead of the bolt, turning the rifle into a blowback weapon.  The round was fully chambered, the bolt just didn't turn to lock up with the lugs.  When the round was fired, the pressure in the case caused the case sides to be pressed up against the chamber and the case head to be pressed against the bolt.  Normally, this pressure on the bolt would be taken up by the locking lugs on the barrel extension, but instead the case head continued to move backwards causing the case to rupture.  This is why the the front of the case was still in the chamber.  Once the case had ruptured, the gas pressure forced the bolt and carrier back at a much higher velocity than normal.  Since the key was missing, the only thing to stop the carrier's movement was the end of the buffer tube.  This is why the buffer tube broke.

Just to clarify, the charging handle does not engage the gas key when it is pulled back, it engages bolt carrier at the point where it is machined flat in front of the gas key and cam pin hole.  If the gas key is missing, the charging handle will still work in the normal manner and will not engage the cam pin.

If the mag is still intact and it wasn't blown out the bottom of your rifle, I would venture to guess that all your parts are still okay to use with the exception of the buffer tube, of course.  But without looking it over, I wouldn't take my word for it.

Quoted: My homie Creeper actually bought all of that stuff from ************ and it's all made of quality RRA components so I highly doubt the rifle is to blame. However he did put it together himself so he might be at fault for improper assembly. Either that or the cheap shit ammo he was using. Edit: I edited out the name of the company because it appears that most people seem to think that the company Creeper bought it from is responsible. I highly doubt that's the case. I tried to tell him to take the upper and lower to a qualified smith for assembly but he was intent on doing it himself. I spent quite a bit of money with the company he ordered the upper from, they've taken good care of me every time I've ordered something. I have no doubt if it is the company's fault that they will take care of the customer.

I wish you would not censor yourself on this, I think alot of us (even from the other thread in Glocktalk) want to know what dealer this is.

Quoted: Quoted: Quoted: I can't blame the guy for getting the upper and lower separately, who here doesn't want to save money? Me. As you can see, it's false economy. This is why I always recommend a newbie buy a factory gun. Quoted: How would anybody ever learn to build one if they never start? Well it would help to download the damned TM and at least have a guide to follow. Well, I won't be building it for at least a few weeks. I'm getting all of the information I can get before hand. I will be asking more questions and getting it looked at by a pro before I shoot it. I'm not building the upper because I don't have the tools or knowledge to do it, I'm only building the lower. I know that's important too though. I'm not dumb enough to attempt this blindly.

Lower assembly is much easier than upper assembly. There only are about 30 parts in the lower and with the exception of roll pins, go together very easily. No special vices are required nor are you putting incredible amounts of torque on barrel nuts. All you might need in terms of "special" tool is a stock wrench and a detent installation tool. The rest you can get at a hardware store. Just look at any one of the number of posts on this forum as to how you go about putting a lower together.

Quoted: Gunzilla called it.  On the fourth round, the carrier turned instead of the bolt, turning the rifle into a blowback weapon.  The round was fully chambered, the bolt just didn't turn to lock up with the lugs.  When the round was fired, the pressure in the case caused the case sides to be pressed up against the chamber and the case head to be pressed against the bolt.  Normally, this pressure on the bolt would be taken up by the locking lugs on the barrel extension, but instead the case head continued to move backwards causing the case to rupture.  This is why the the front of the case was still in the chamber.  Once the case had ruptured, the gas pressure forced the bolt and carrier back at a much higher velocity than normal.  Since the key was missing, the only thing to stop the carrier's movement was the end of the buffer tube.  This is why the buffer tube broke. Just to clarify, the charging handle does not engage the gas key when it is pulled back, it engages bolt carrier at the point where it is machined flat in front of the gas key and cam pin hole.  If the gas key is missing, the charging handle will still work in the normal manner and will not engage the cam pin. If the mag is still intact and it wasn't blown out the bottom of your rifle, I would venture to guess that all your parts are still okay to use with the exception of the buffer tube, of course.  But without looking it over, I wouldn't take my word for it.

Quoted: Creeper1313 Check the chamber in the barrel! I'm a bit concerned that on the Kaboom round the bullet may have jumped a gap between the chamber and the barrels bore thus using the chamber like a funnel for the bullet to make it's way down the barrel.  While the chamber  in an AR is supposed to be good to like 53,000psi the effects of a bullet jumping a gap between a chamber and the bore may have damaged the barrel too!

From jason_h's description, it sounds like I didn't have a true "kaboom" but rather the bolt just sorta flew back and tore the back of the shell casing off, and with no gas key, it just kept flying back, compressed the whole buffer spring, and still had enough energy to crack my buffer tube off. The mag was still fine and wasn't blown out the bottom. From visual inspection, I can't see any damage to the inside of the   receiver.

In response to Daubs: Is there any way to tell if there is a gap between my barrel and chamber without taking the upper completely apart? The reason I got the "complete" upper is because I lack the tools to put one together.  I shined a bright flashlight in through the bottom of the upper while looking up the bore and I couldn't see any noticible damage to the bore or the chamber, but it's hard to say if there's a gap between them.

If there is no way to tell, I'm inclined to just ask for a new upper from the dealer or have them reassemble this one.  If I can determine there is no problem with the barrel, I think I'd just need the gas key, the bolts to install it, a new buffer tube, and a detent spring that went missing. Or I could just get these parts and have a gunsmith inspect my upper... but I don't want to sink money into a problem that I think the dealer shares much of the responsibility for.

Some people have scolded me for my oversight and said "newbies should just buy a complete factory rifle" and to some extent they are correct... However, shouldn't you be able to expect a RRA "complete upper" be no different from a RRA complete rifle, just minus the assembled lower? Well I've learned my lesson and will be inspecting everything from now on with the help of a reference book.... Had the gas key been missing from a complete rifle, I wouldn't have noticed it either and the end result would have been the same!

Quoted: In response to Daubs: Is there any way to tell if there is a gap between my barrel and chamber without taking the upper completely apart? The reason I got the "complete" upper is because I lack the tools to put one together.  I shined a bright flashlight in through the bottom of the upper while looking up the bore and I couldn't see any noticible damage to the bore or the chamber, but it's hard to say if there's a gap between them.

You made a mistake and we all do it from time to time....  If this did come from a dealer I would be on the phone with them expressing extreeme disdane for the problem you had as this thing could have removed your head as easily as it tore out the rear of your receiver....

Did you ever say what part of PA you live in?  I have all the tools that would be needed to look at your upper/lower and I have built more ARs then I care to count...  I am located near Valley Forge PA (SE Pennsylvania) and I would be glad to help...  

QB

I'm over in York, PA and I've got most of the tools for rebarreling and such.

I'd be happy to help as well.

Quoted: In response to Daubs: Is there any way to tell if there is a gap between my barrel and chamber without taking the upper completely apart? The reason I got the "complete" upper is because I lack the tools to put one together.  I shined a bright flashlight in through the bottom of the upper while looking up the bore and I couldn't see any noticeable damage to the bore or the chamber, but it's hard to say if there's a gap between them.

I guess I didn't come across too clear.  What I was concerned about was the round being fired out of battery.  I.E. the bullet case wasn't seated all the way into the chamber.  After reading jason_h's post I may be wrong about the round not being fully chambered when fired.

Basically, if you didn't see any chips, cracks, or gouges inside where the chamber meets the bore you should be OK. But don't hold me to that.

Quoted: Since you bought parts only, you assumed the responsibility of having the knowledge and tools to assemble the parts in to a weapon. And test the parts and assembly at your own risk short of parts failure.

Creeper bought a COMPLETE upper!  Their SHOULDN"T have been anything for him to assemble.  I feel the company he bought the upper from is responsible.  Product liability law would sight did the accident result from the company's negligence in constructing the upper.  ANSWER YES, a missing carrier key!  The company he bought from should be bending over backwards kissing his A$$, thus a whole new complete upper plus missing / broken parts replacement is the least they can do.  The company negligently assemled the upper.

here is a lesson for you all:

ULTRAMAX BLOWS UP FUCKING RIFLES...

happened to me... snapped charging handle in half, twised carrier in upper, froze bolt in the lugs, blew off extractor, blew remaining rounds, floor plate and spring out of mag, ruined mag body, blew out sides of lower...

stay AWAY from factory reloads and ALL ULTRAMAX...

Come on, tell us... who made the upper ?

Oh please..... while UM ammo has blown up a gun or two..... this aint about ammo.

As to the complete upper.... I agree... thats the seller's responsibility.  Complete uppers are a two pin snap on operation.... HARDLY building a rifle.  It should come complete, headspaced, and ready to fire.

Great lesson to all tho.... to inspect everything, and dont trust anything when you arent buying a factory rifle.