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Posted: 2/4/2016 12:37:47 PM EDT
I recently bought a Colt BCG and upper from a member here that were said to be new take offs. I received them and everything looked fine upon first inspection, the machining on the new bolt carrier actually looked nice. I went to clean the BCG today and noticed something strange. A gas ring nearly came off the tail of the bolt while I was wiping the grease off. Upon closer inspection, the groove that the rings sit in is not machined the way my other Colt bolts are.The gas move around about twice as much as on my other BCGs.

This is an example of one of my other Colt BCGs (stamped C on bolt carrier):


This is the new BCG (dot C on the bolt carrier):


This is both of the bolts together:


My first question is- Is this a genuine Colt BCG?
Link Posted: 2/4/2016 12:45:22 PM EDT
[#1]
Wow, have never seen one like that before, Colt or not.
Link Posted: 2/4/2016 1:31:29 PM EDT
[#2]
I see it's stamped MPC for Colt, are you sure the gas rings are not enlarged?
Link Posted: 2/4/2016 1:41:37 PM EDT
[#3]
There is a flare cut into the groove instead of just being a straight wall. The gas rings seem normal to me.
Link Posted: 2/4/2016 1:42:33 PM EDT
[#4]
Your BCG is genuine Colt, at least it appears to be so judging from the pics.
The rings will compress when bolt is inserted into  carrier.
If the rings appear suspect, replace them with new ones.
Link Posted: 2/4/2016 1:57:04 PM EDT
[#5]
So how does it shoot?
Link Posted: 2/4/2016 2:57:07 PM EDT
[#6]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Your BCG is genuine Colt, at least it appears to be so judging from the pics.
The rings will compress when bolt is inserted into  carrier.
If the rings appear suspect, replace them with new ones.
View Quote


I know the rings will compress and there won't be as much slop when installed. However, the bolt drawing that is online doesn't show any radius or chamfer on those edges.

My second question is- Are all new Colt bolts like this?
Link Posted: 2/4/2016 3:13:44 PM EDT
[#7]
There also seems to be a lot of axial wiggle room for the rings to move back and forth, not sure how that plays out for the rings over time. I wouldn't be happy with that at all. It might work for a while , but who knows for how long.
Link Posted: 2/4/2016 3:35:43 PM EDT
[#8]
I have a month old 6720, I'll check it later and report back on the bolt.
Link Posted: 2/4/2016 4:32:02 PM EDT
[#9]
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Quoted:
There also seems to be a lot of axial wiggle room for the rings to move back and forth, not sure how that plays out for the rings over time. I wouldn't be happy with that at all. It might work for a while , but who knows for how long.
View Quote


That's one thing I was worried about.
Link Posted: 2/4/2016 4:32:39 PM EDT
[#10]
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Quoted:
I have a month old 6720, I'll check it later and report back on the bolt.
View Quote


I'd appreciate it. I ask anyone with a current production to check.
Link Posted: 2/4/2016 5:03:06 PM EDT
[#11]
It appears there is a small angle cut on the tail end side of the lugs.  Am I seeing that right?

" />
Link Posted: 2/4/2016 5:13:03 PM EDT
[#12]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
It appears there is a small angle cut on the tail end side of the lugs.  Am I seeing that right?

http://<a href=http://i1292.photobucket.com/albums/b573/dkoetting/DSC_0340_zpsjzc8xd6g.jpg</a>" />
View Quote



That is normal.  So what?
Link Posted: 2/4/2016 5:26:36 PM EDT
[#13]
Discussion ForumsJump to Quoted PostQuote History
Quoted:



That is normal.  So what?
View Quote View All Quotes
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Discussion ForumsJump to Quoted PostQuote History
Quoted:
Quoted:
It appears there is a small angle cut on the tail end side of the lugs.  Am I seeing that right?

http://<a href=http://i1292.photobucket.com/albums/b573/dkoetting/DSC_0340_zpsjzc8xd6g.jpg</a>" />



That is normal.  So what?


My apologies, never noticed that before.
Link Posted: 2/4/2016 5:52:06 PM EDT
[#14]
Can you get some dimensions off of that bolt??

Angled cuts on the lugs is pretty standard.
Link Posted: 2/4/2016 5:58:17 PM EDT
[#15]
I left my calipers at work but will be able to measure and check it against the drawing tomorrow.
Link Posted: 2/4/2016 7:29:23 PM EDT
[#16]
Don't look normal.
But it's a colt so it must be milspec
Link Posted: 2/4/2016 8:10:22 PM EDT
[#17]
That bolt is not right.
Link Posted: 2/4/2016 8:14:57 PM EDT
[#18]
Good thing you didn't cheap out and go with a PSA or AIM or ToolCraft  Wouldn't want a bolt that wasn't messed up since it doesn't have that C on the side .  J/K, I am surprised to see this out of a Colt honestly.  I have never heard any bad reviews on a Colt BCG and it seems you just had really really bad luck on this one.  I hope the seller didn't sell it to you because he knew about this.  It is something that looks like it would be fairly evident even on the initial inspection.
Link Posted: 2/4/2016 8:33:51 PM EDT
[#19]
Discussion ForumsJump to Quoted PostQuote History
Quoted:


My apologies, never noticed that before.
View Quote View All Quotes
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Discussion ForumsJump to Quoted PostQuote History
Quoted:
Quoted:
Quoted:
It appears there is a small angle cut on the tail end side of the lugs.  Am I seeing that right?

http://<a href=http://i1292.photobucket.com/albums/b573/dkoetting/DSC_0340_zpsjzc8xd6g.jpg</a>" />



That is normal.  So what?


My apologies, never noticed that before.


Some of them are very small, almost not there.
Link Posted: 2/4/2016 8:44:39 PM EDT
[#20]
Do you think that maybe the bolt was swapped? Or is it properly marked?
Link Posted: 2/4/2016 9:00:46 PM EDT
[#21]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Do you think that maybe the bolt was swapped? Or is it properly marked?
View Quote


It is MPC marked (the C is supposedly for Colt). It should be Colt unless there are fakes out there.
Link Posted: 2/4/2016 9:12:15 PM EDT
[#22]
You know a company is in trouble when they move to dot matrix markings lol.
Link Posted: 2/4/2016 11:21:22 PM EDT
[#23]
Bolt looks fouled. Get a new bolt.
Link Posted: 2/5/2016 2:35:37 AM EDT
[#24]
Discussion ForumsJump to Quoted PostQuote History
Quoted:


It is MPC marked (the C is supposedly for Colt). It should be Colt unless there are fakes out there.
View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Quoted:
Do you think that maybe the bolt was swapped? Or is it properly marked?


It is MPC marked (the C is supposedly for Colt). It should be Colt unless there are fakes out there.


Does it have a white dot that is there for hardness testing?

I have 2 BCG's that use a dot type C and MPC so that's normal, but that bolt is all sorts of fucky.
Link Posted: 2/5/2016 6:07:39 AM EDT
[#25]
Call Colt, send the bolt back for a replacement.
Link Posted: 2/5/2016 7:16:16 AM EDT
[#26]
It should not make any difference in function of longevity.

A chamfer or radius will just make removing/installing the rings easier.
Link Posted: 2/5/2016 11:23:27 AM EDT
[#27]

Discussion ForumsJump to Quoted PostQuote History
Quoted:


You know a company is in trouble when they move to dot matrix markings lol.
View Quote
So you think Daniel Defense is in trouble?

 
Link Posted: 2/5/2016 11:41:54 AM EDT
[#28]
Colt replied to my contact (including a picture) and is wanting the bolt to inspect.
Link Posted: 2/5/2016 11:46:09 AM EDT
[#29]
Discussion ForumsJump to Quoted PostQuote History
Quoted:


Does it have a white dot that is there for hardness testing?

I have 2 BCG's that use a dot type C and MPC so that's normal, but that bolt is all sorts of fucky.
View Quote View All Quotes
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Discussion ForumsJump to Quoted PostQuote History
Quoted:
Quoted:
Quoted:
Do you think that maybe the bolt was swapped? Or is it properly marked?


It is MPC marked (the C is supposedly for Colt). It should be Colt unless there are fakes out there.


Does it have a white dot that is there for hardness testing?

I have 2 BCG's that use a dot type C and MPC so that's normal, but that bolt is all sorts of fucky.


It doesn''t have the large paint dot on it.
Link Posted: 2/5/2016 12:57:26 PM EDT
[#30]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Call Colt, send the bolt back for a replacement.
View Quote


Not that simple.  They ask for the serial number of the rifle.  I doubt they will warrant parts purchased from private party.  
I would contact the seller of this upper and let him deal with Colt.



Link Posted: 2/5/2016 2:27:30 PM EDT
[#31]


Discussion ForumsJump to Quoted PostQuote History
Quoted:
Not that simple.  They ask for the serial number of the rifle.  I doubt they will warrant parts purchased from private party.  


I would contact the seller of this upper and let him deal with Colt.
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Quoted:





Quoted:


Call Colt, send the bolt back for a replacement.






Not that simple.  They ask for the serial number of the rifle.  I doubt they will warrant parts purchased from private party.  


I would contact the seller of this upper and let him deal with Colt.
Nevermind, misunderstood.
Link Posted: 2/5/2016 5:30:35 PM EDT
[#32]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
You know a company is in trouble when they move to dot matrix markings lol.
View Quote


Newb, all USGI bolts since they started being marked are done this way. If you're thinking of laser engraving, that's purely a commercial market process.
Link Posted: 2/5/2016 6:21:45 PM EDT
[#33]
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Quoted:
Can you get some dimensions off of that bolt??

Angled cuts on the lugs is pretty standard.
View Quote


Everything I can accurately measure was within spec except the radius.
Link Posted: 2/5/2016 6:27:48 PM EDT
[#34]
Link Posted: 2/5/2016 8:23:41 PM EDT
[#35]
Discussion ForumsJump to Quoted PostQuote History
Quoted:


Newb, all USGI bolts since they started being marked are done this way. If you're thinking of laser engraving, that's purely a commercial market process.
View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Quoted:
You know a company is in trouble when they move to dot matrix markings lol.


Newb, all USGI bolts since they started being marked are done this way. If you're thinking of laser engraving, that's purely a commercial market process.


It's acid etching, no?
Link Posted: 2/5/2016 8:30:06 PM EDT
[#36]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
So you think Daniel Defense is in trouble?  
View Quote View All Quotes
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Discussion ForumsJump to Quoted PostQuote History
Quoted:
Quoted:
You know a company is in trouble when they move to dot matrix markings lol.
So you think Daniel Defense is in trouble?  

Where on a Daniel Defense rifle are the markings made via dot matrix?
Link Posted: 2/5/2016 8:31:12 PM EDT
[#37]
Discussion ForumsJump to Quoted PostQuote History
Quoted:


Newb, all USGI bolts since they started being marked are done this way. If you're thinking of laser engraving, that's purely a commercial market process.
View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Quoted:
You know a company is in trouble when they move to dot matrix markings lol.


Newb, all USGI bolts since they started being marked are done this way. If you're thinking of laser engraving, that's purely a commercial market process.

Stamping and dot matrix are different processes.
Link Posted: 2/6/2016 10:36:23 AM EDT
[#38]
Colt bolts (not bolt carriers) have the markings ãcid etched.
Link Posted: 2/6/2016 11:54:44 AM EDT
[#39]
I checked three of my Colt bolts.  They are all marked like yours, even with the dot looking method of marking, and in the same spot.  None have the angled cut on the lugs, as pronounced, but yours could just have been made by a different sub-contractor.

I do believe yours is genuine Colt, but I don't think the gas ring cut was made correctly.  I wonder if it came out of one of the competition models.  The ones that are not made by Colt, but sold as Colt under license.  What model upper are we talking here?
Link Posted: 2/6/2016 12:04:17 PM EDT
[#40]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
It should not make any difference in function of longevity.

A chamfer or radius will just make removing/installing the rings easier.
View Quote


I don't think that is true.  Based on how much the rings are tilting to the side, I don't think those rings are properly captured, even when assembled in the carrier and compressed.  The OP could tell us how the bolt feels installed.  If it has play when manipulated in the forward and aft directions, it indicates an unacceptable condition.  If the groove is properly dimensioned towards the bottom, and the rings are "tall" enough to reach the tighter groove when assembled and compressed, then I would call it a non-issue.
Link Posted: 2/6/2016 12:46:50 PM EDT
[#41]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
I checked three of my Colt bolts.  They are all marked like yours, even with the dot looking method of marking, and in the same spot.  None have the angled cut on the lugs, as pronounced, but yours could just have been made by a different sub-contractor.

I do believe yours is genuine Colt, but I don't think the gas ring cut was made correctly.  I wonder if it came out of one of the competition models.  The ones that are not made by Colt, but sold as Colt under license.  What model upper are we talking here?
View Quote


It was a 2015 6920 that was parted out.
Link Posted: 2/6/2016 12:48:59 PM EDT
[#42]
Discussion ForumsJump to Quoted PostQuote History
Quoted:


I don't think that is true.  Based on how much the rings are tilting to the side, I don't think those rings are properly captured, even when assembled in the carrier and compressed.  The OP could tell us how the bolt feels installed.  If it has play when manipulated in the forward and aft directions, it indicates an unacceptable condition.  If the groove is properly dimensioned towards the bottom, and the rings are "tall" enough to reach the tighter groove when assembled and compressed, then I would call it a non-issue.
View Quote View All Quotes
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Discussion ForumsJump to Quoted PostQuote History
Quoted:
Quoted:
It should not make any difference in function of longevity.

A chamfer or radius will just make removing/installing the rings easier.


I don't think that is true.  Based on how much the rings are tilting to the side, I don't think those rings are properly captured, even when assembled in the carrier and compressed.  The OP could tell us how the bolt feels installed.  If it has play when manipulated in the forward and aft directions, it indicates an unacceptable condition.  If the groove is properly dimensioned towards the bottom, and the rings are "tall" enough to reach the tighter groove when assembled and compressed, then I would call it a non-issue.


It is more difficult to insert into the carrier but after it is installed it feels the same as a normal bolt. I'm worried about the part not being made to spec, regardless if it functions or not.
Link Posted: 2/6/2016 7:00:46 PM EDT
[#43]
FWIW, I recently bought a 6921 upper new(would have to look at build date) and the rings look normal, not like the OP.  On a side note, the bolt in that upper was marked with a "C" but there are no markings what so ever on the bolt itself.
Link Posted: 2/6/2016 9:23:50 PM EDT
[#44]
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Quoted:


It was a 2015 6920 that was parted out.
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Quoted:
Quoted:
I checked three of my Colt bolts.  They are all marked like yours, even with the dot looking method of marking, and in the same spot.  None have the angled cut on the lugs, as pronounced, but yours could just have been made by a different sub-contractor.

I do believe yours is genuine Colt, but I don't think the gas ring cut was made correctly.  I wonder if it came out of one of the competition models.  The ones that are not made by Colt, but sold as Colt under license.  What model upper are we talking here?


It was a 2015 6920 that was parted out.


Why is someone parting out a 2015 6920 is what im interested in
Link Posted: 2/6/2016 9:32:54 PM EDT
[#45]
Discussion ForumsJump to Quoted PostQuote History
Quoted:


Why is someone parting out a 2015 6920 is what im interested in
View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Quoted:
Quoted:
I checked three of my Colt bolts.  They are all marked like yours, even with the dot looking method of marking, and in the same spot.  None have the angled cut on the lugs, as pronounced, but yours could just have been made by a different sub-contractor.

I do believe yours is genuine Colt, but I don't think the gas ring cut was made correctly.  I wonder if it came out of one of the competition models.  The ones that are not made by Colt, but sold as Colt under license.  What model upper are we talking here?


It was a 2015 6920 that was parted out.


Why is someone parting out a 2015 6920 is what im interested in


Sounds odd but it happens quite a bit. I've bought most of my Colt upper parts as new 6920 take offs from the EE.
Link Posted: 2/7/2016 12:26:45 PM EDT
[#46]



Discussion ForumsJump to Quoted PostQuote History
Nm
View Quote


 
Link Posted: 2/7/2016 1:39:35 PM EDT
[#47]
Discussion ForumsJump to Quoted PostQuote History
Quoted:


Sounds odd but it happens quite a bit. I've bought most of my Colt upper parts as new 6920 take offs from the EE.
View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Quoted:
Quoted:
Quoted:
I checked three of my Colt bolts.  They are all marked like yours, even with the dot looking method of marking, and in the same spot.  None have the angled cut on the lugs, as pronounced, but yours could just have been made by a different sub-contractor.

I do believe yours is genuine Colt, but I don't think the gas ring cut was made correctly.  I wonder if it came out of one of the competition models.  The ones that are not made by Colt, but sold as Colt under license.  What model upper are we talking here?


It was a 2015 6920 that was parted out.


Why is someone parting out a 2015 6920 is what im interested in


Sounds odd but it happens quite a bit. I've bought most of my Colt upper parts as new 6920 take offs from the EE.


It's true. I recently bought a brand new barrel off of a 6920 as a takeoff.
Link Posted: 2/7/2016 5:47:15 PM EDT
[#48]
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Quoted:
Colt replied to my contact (including a picture) and is wanting the bolt to inspect.
View Quote


Did you/are you going to send it to them? I think they're going to keep your bolt and send out a replacement.
Link Posted: 2/7/2016 6:41:38 PM EDT
[#49]
I would send it to them if they'd take it and get one that isn't questionable.  I can't blame whoever parted it out for parting it out once they seen the bolt.  Colt is a great company and probably one of the top 5 AR15 manufacturers but everyone is capable of mistakes and after producing so many rifles eventually there is going to be a problem with one of them.  The QC department really should have caught this but perhaps they were taking a smoke break when this bolt went through their station.  Same thing could have happened on a DD, BCM, FN, etc.  And is another reason I am often happy with a cheaper PSA or ToolCraft and to do my own QC inspection upon arrival for half the price.
Link Posted: 2/7/2016 7:00:09 PM EDT
[#50]
Discussion ForumsJump to Quoted PostQuote History
Quoted:


Why is someone parting out a 2015 6920 is what im interested in
View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Quoted:
Quoted:
Quoted:
I checked three of my Colt bolts.  They are all marked like yours, even with the dot looking method of marking, and in the same spot.  None have the angled cut on the lugs, as pronounced, but yours could just have been made by a different sub-contractor.

I do believe yours is genuine Colt, but I don't think the gas ring cut was made correctly.  I wonder if it came out of one of the competition models.  The ones that are not made by Colt, but sold as Colt under license.  What model upper are we talking here?


It was a 2015 6920 that was parted out.


Why is someone parting out a 2015 6920 is what im interested in


People do it all the time.  Usually they're just wanting the "M4 Carbine" marked lower for a clone build.
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