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4/29/2011 10:27:40 AM EDT
I need some advice, but I think that I may have some new 7075 aluminum fishing weights on my hands.  I recently wanted to change out a barrel on a Colt 6520.  So I traded out my light weight barrel for a M4 gov profile barrel.  In doing so, I did not want to have to SBR the weapon, so I premanently attached an extended A2 flash hider.  So when I took it in to get put together, and I had always done before, I took it to the local shop that I have over time built up a really good rapport with.  When they were attaching the barrel to the upper, the post that slips into the notch was not aligned, and when my buddy gave it a little tap, CRACK!!!  There is a crack just behind where the notch it cut....  and there went me project...  

Is there anything that can be done, or do I now have some really expensive aluminum that I can use as a paper weight?  I am guessing that I am SOL.  I am thinking that once the integrity of upper is gone with that crack, it can no longer be used.  Any feed would be appreciated.  Really appreciate the help.  

PCW
4/29/2011 10:33:25 AM EDT
[#1]
I personally wouldn't use it with that crack. It's liable to spread further when the rifle is fired. Good news is that many people replace their 6520 A2 upper receivers with A4 receivers, so they show up from time to time on the EE.
4/29/2011 12:02:56 PM EDT
[#2]
the"local shop" owes you a new receiver

ETA: got pics?
4/29/2011 12:40:25 PM EDT
[#3]
not sure why..  but I am not able to see any new posts...
4/29/2011 12:42:54 PM EDT
[#4]
well.. i dont wanna make it big deal, they always assemble and disassemble and never charge me.  but I think that i am going to go ahead start my own assembling and work as such..  not gonna pin it on them, but like you said earlier, I think that I will just post a WTB Colt 6520 upper...  i am sure that something will come up.  As for pics.. i will try to take some tonight and post later.  alrt. thanks guys.  
4/29/2011 4:58:35 PM EDT
[#5]
Probably could be fixed but not cost effective.  I'll take it if throwing it away,  and might be able to weld and repair.  I now believe that anything is possible.  That is what I call bad luck.  Sorry for your misfortune.  I knew there was a reason I build my own.  Can't believe you traded a LW barrel for a M-4 profile.  Did you get some extra cash too?
4/29/2011 9:00:00 PM EDT
[#6]
Sounds like they disregarded the 30-80 ft pound spec and tightened the hell out of it. By yourself a bench/vise if you do not already have one, and start doing this work yourself to ensure it's done correctly. It's an easy job after you do a few. Really, these guys owe you a new upper.
4/29/2011 9:01:32 PM EDT
[#7]
www.fidelisfirearms.com. They have brand new 6520 uppers for $189. I bought one once and it was superb. They are new take offs.
4/29/2011 9:42:03 PM EDT
[#8]
Quoted:
Sounds like they disregarded the 30-80 ft pound spec and tightened the hell out of it. By yourself a bench/vise if you do not already have one, and start doing this work yourself to ensure it's done correctly. It's an easy job after you do a few. Really, these guys owe you a new upper.


well, I just reread your post and it sounds like they didnt even get around to tightening the barrel nut yet. If things are not aligned that little tap can be a deal breaker. Definitely sounds like inexperience on the part of the shop. No reason for this to happen...it takes a major F'up to crack things.

4/30/2011 5:12:05 PM EDT
[#9]
i still get no updates on the topic..  does anyone know what may be wrong
4/30/2011 5:14:27 PM EDT
[#10]
I agree, the dude dropped the ball, but lI saw one of them on Fidelis Firearms...  gonna make the purchase as soon as i make contact.  

thanks for all the help guys..
4/30/2011 6:17:43 PM EDT
[#11]
Yep, it's the shops fault! You don't need to over tighten it at all!
4/30/2011 6:23:39 PM EDT
[#12]
Quoted:
i still get no updates on the topic..  does anyone know what may be wrong

Try logging out, clearing your cookies and cache, and logging back in.
5/1/2011 2:35:09 PM EDT
[#13]
From what I gathered.. nothing was even tightened...  the post atop the barrel at the 12 o'clock position was not properly aligned into the notch, and the little tap was enough force to crack the upper.  My buddy offered to get me another, but I don't think it should be on him...  If anything, it is the establishments responsibility..  but Im not gonna let this sour a friendship.  I have already sent an email to Fidelis Firearms, just waiting on the response.  I will try to post pictures tonight.  Just been so busy..
5/1/2011 9:44:01 PM EDT
[#14]
Fidelis will hook you up. I got one from them and it was mint with M4 feedramps.
5/2/2011 12:34:56 AM EDT
[#15]
I don't like the sound of this AT ALL...

If the notch wasn't aligned, why would you give it a tap?  I expect that you'd align it first...

Second, if the "tap" was in fact rotational, meant to align the pin, I fail to understand how this could cause a crack...

Finally, the crack just behind the notch sounds, to me, almost like the put the pin in the notch and started wrenching on the barrel nut, overtightened it, and thus effectively turned the pin into a wedge and then splitting the upper...
5/2/2011 12:00:50 PM EDT
[#16]
Any one check the diameter of the barrel extension?

Brick
5/2/2011 1:25:08 PM EDT
[#17]
Quoted:
Any one check the diameter of the barrel extension?

Brick


You know thats actually a very, very good point...What about the width of the alignment pin while we're at it...I imagine an oversize alignment pin could cause the same problem.
5/2/2011 6:28:46 PM EDT
[#18]
Whole deal sounds a little screwy.  Did you trade for a Colt M-4 barrel?  or  Did you trade for some POS M-4 barrel?  You sound easy going enough but something stinks about this deal.  Wish I could look at those parts.
5/3/2011 8:44:41 AM EDT
[#19]
The parts are a complete Colt 6520.  I ended up trading for a Colt M4 Profile barrel with A2 FSB...  No F-mark, which is what I had wanted.  To keep it completely COlt, and the A2 FSB so that it would match the A2 upper from the 6520.  I know that all you gus really want to see pictures, so I will post them here in a bit.  I was going to post this other problem that came up, but I guess I will ask you guyus first.  

Q Can a barrel with a pinned Ext. A2 Flash-hider be mounted on the upper with out having to remove it?  

The guy putting it together with me told me that it has to come off..  When I asked Steve at Adco, he said it wouldn't matter if I sent him just the barrel, or the upper assembled.  By what Steve's response, I am guessing that it is not a problem to mount a barrel with an perm. attached Ext. A2 flash-hider.  I'm so confused, and I have to learn to do this work myself.  I hope that you guys could help.

Gabe
5/3/2011 10:56:21 AM EDT
[#20]
It depends on if you have all the parts you need on the barrel.  For example, the barrel nut, hand guard ring and front site base.  If those things are not on before you pin the hider, then the hider has to come off for them to be put on.

It is also possible your cracked upper had a flaw or week spot in the metal.  Might be easier to tell with pics of it.

Brick
5/3/2011 1:45:48 PM EDT
[#21]
I just took a look at what I was left with..  The barrel nut, delta ring and sring are in place.  The pins on the FSB have been removed, but is still in place along with the hadgaurd cap.  I hope this helps, and will have opictures up soon.  

Gabe
5/3/2011 2:25:30 PM EDT
[#22]
How the hell do I upload photos on this forum.  I am really new to the community..
5/4/2011 12:33:17 AM EDT
[#24]
Kinda looks like you were told.  Appears like the guy doing the work was buzzed.  Looks like he wasn't lined up when he hit it as previously stated.  I'm guessing it was either dropped or he was drinking.  Damage appears on wrong side for over tightening in my opinion.  Might have been done when removing previous barrel.  Sure has the dropped look.  Any nicks anywhere else.   Thinking only one person actually knows.  Your M-4 barrel appears to be genuine Colt.  

It looks like a Colt barrel assembly and FH won't have to come off to install on another upper.  You will need to put taper pins back in FSB.  Again sorry for your misfortune.  Not a cheap screw up.  Who took the pins out of the FSB and why?  A little doesn't add up there.  How long is the barrel 14.5"?  Did you remove the taper pins or like it when you got it?  May have to install a taller front sight post to zero at short distances.  No big deal.  I'd try it first.  Probably can repair the upper but it could cost more than it's worth to fix and re-finish unless you know a decent welder.  Grind it, weld it,  grind it, paint it or re-finish it.  That's a first for me.  If you get tired of living with screw up send it to me.
5/4/2011 5:20:43 AM EDT
[#25]
Quoted:
Kinda looks like you were told.  Appears like the guy doing the work was buzzed.  Looks like he wasn't lined up when he hit it as previously stated.  I'm guessing it was either dropped or he was drinking.  Damage appears on wrong side for over tightening in my opinion.  Might have been done when removing previous barrel.  Sure has the dropped look.  Any nicks anywhere else.   Thinking only one person actually knows.  Your M-4 barrel appears to be genuine Colt.  

It looks like a Colt barrel assembly and FH won't have to come off to install on another upper.  You will need to put taper pins back in FSB.  Again sorry for your misfortune.  Not a cheap screw up.  Who took the pins out of the FSB and why?  A little doesn't add up there.  How long is the barrel 14.5"?  Did you remove the taper pins or like it when you got it?  May have to install a taller front sight post to zero at short distances.  No big deal.  I'd try it first.  Probably can repair the upper but it could cost more than it's worth to fix and re-finish unless you know a decent welder.  Grind it, weld it,  grind it, paint it or re-finish it.  That's a first for me.  If you get tired of living with screw up send it to me.


The guy wasn't drinking..  I just think that he was in a hurry...  I just heard some tapping and he came out with a borken upper.  The rifle was new...  I bought, took the barrel off, set the rest aside, until I got me the barrel that I had wanted.  The barrel is a 14.5" Gov't Profile barrel with an A2 FSB (No F-Mark).  As for the broken upper, I really dont know what I will do with it..  I was thinking that once the integrity of the Aluminum is cracked in such a matter, that it was a done deal due to all the chamber pressure and what not.  Nonetheless, I am going to have a good friend of mine take a look at the parts kit, and he will let me know if he can put it together.  If not, I would be more than happy to send this out to you to get put together.  As for the broker upper, if it could actually be fixed..  that me be a long term project..
5/4/2011 5:54:34 AM EDT
[#26]
after looking at the pics, I'd perhaps use it for a dedicated .22LR build.. just because you don't really have to put a lot of torque on the barrel nut of a .22LR set up. And if I were to use it for a build, I'd drill a small hole at the end of the crack to keep it from spreading any further.
5/4/2011 7:38:21 AM EDT
[#27]
My guess would be he tried to slide the barrel in and it only went in a little bit and stopped.  He tried to tap it in and didn't hit a straight on blow causing the barrel flex against the receiver's threaded nose and causing the crack.  The crack released some of the pressure and the barrel slid back till it hit the pin slot causing the large ding on the port side of the slot.

Brick
5/4/2011 8:12:44 AM EDT
[#28]
Dedicated .22lr build is a good idea.
5/4/2011 10:06:49 AM EDT
[#29]
Quoted:
after looking at the pics, I'd perhaps use it for a dedicated .22LR build.. just because you don't really have to put a lot of torque on the barrel nut of a .22LR set up. And if I were to use it for a build, I'd drill a small hole at the end of the crack to keep it from spreading any further.

Good idea on drilling the hole.
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