Do the Colt 6920 (16" M4) semi auto uppers have a full circle or half circle bolt carrier?

Mick

Mine had the half circle.

It's a half moon.

The two that I bought within the past year both had the half-moon carriers.

Half moon, non-shrouded pin, C AF, M4 feedramps, but no 4 or M4 markings up front

No RAS numbers either

Hmmm.  My 6920 has the half moon, non-shrouded pin carrier, C AF marked upper receiver, M4 feedramps, the RAS numbers and the M4 markings.  I purchased mine in 2002.  My guess is that the newer ones do and the older ones do not but then again, with Colt, you never know.

Since we are getting into detail about our LE6920s. Mine, once again, has the half-moon bolt carrier.
It has a Diemaco (D A stamped)upper receiver.
It has an Alcoa Forge (AF 1 stamped)carry handle.
The bolt and carrier are Colt (C and MPC stamped).
The barrel is a Colt (C MP) stamped 1/7.
It has the M4 stamp just above the gas port on the front of the upper. It has M4 feed ramps. It does not have the RAS numbers on the flat-top.

It is a brand new rifle, purchased in March 2003 from an LE distributor in Texas and has a serial number of LE0080xx.

It has a beautiful finish and functions flawlessly...even better than my service M4 did.

Mine was bought new in 1997.  Two other co-workers bought the same with me, and there's were the same.  

What about lowers-  Mine has a small front pivot pin size, but is still taken apart with a screwdriver.  Its not even drilled for the pivot pin's detent spring.  

Kisara,

How are your bolt and carrier marked?

Is it a flattop upper? Is there a "4" stamped at the 3 o clock position on the rear of the barrel extension? You should be able to see it through the ejection port.

Ok, my mistake.  All my Colts are unshrouded, but this isn't.  I thought it was- but its still a half circle.  
[img]http://www.boomspeed.com/kisara/TWEAKisCOOL.jpg[/img]


Bolt: MP
      C

Bolt Carrier:  C
[img]http://www.boomspeed.com/kisara/HelloTweak.jpg[/img]


Wow Tweak, I never even heard of that little 4 on the extension!  I was looking in the wrong place anyways, and it took awhile to find.  But its there; was a bitch to photograph.
[img]http://www.boomspeed.com/kisara/TWEAK.jpg[/img]

Carry Handle: A-9  (Anchor Harvey's split A )

Front Sight: Stamped F on left, molded 2 on right.

Thanks for all your help, especially Tweak!  I've learned so much just from your posts alone.

Looking at the pic (of the barrel extension) it doesn't look like your upper has the extended ramps. I do see what looks like an small crescent in the front lip of the upper under the feed ramps in the extension but it's no where near big enough to be the extended ramps. Could just be the angle/lighting tho.

[img]http://photos.ar15.com/ImageGallery/Attachments/DownloadAttach.asp?iImageUnq=2881[/img]



Where were you looking? Is there a way to refine my directions?

BTW, nice file names Kisara. [^] Glad to be of service. Sometimes a little bit of white crayon goes a long way in pictures of engraving.

[way wrong smilie]

They look just like the photo on the right.  In contrast, my Bushmasters look like the left photo.   I'm just wondering why they didn't stamp a 4 or M4 in front.  

I was actually looking through the ejection port from the outside.  I guess looking straight in from the back or bottom was easier.
The 4 is so small, the slightest amount of dirt would cover it.  I sprayed a high pressure blast of cleaner ("Powder Blast") all around, and held it in brighter light, and Whammo!  It magically appeared.

The photo names might not appear with fast DSL or Cable, but with slower modems people should see them.  [;)]  I always like to check out the posts in Troubleshooting.  

Actually, I saw them when I quoted your post. Are the feed ramps in your upper anodized or shiny?

All black like the rest of the upper's inside.

I dunno why it's not stamped then.

My 6920 has over 17K rds through it w/o a single malfunction.

My upper by the way is marked C AF , ser #
LE001xxx .

It has the screw off front pin , which snapped after a 3K Carbine Course , I just put in a standard Pin and its held really well.

[img]http://volcano.photobucket.com/albums/0803/coltm4/Firearms/8b209a02.JPG[/img]
[img]http://volcano.photobucket.com/albums/0803/coltm4/Firearms/46b36131.JPG[/img]

Well I was getting more curious about my missing markings by the gas tube, and completely seperated the upper off of the rifle.  I got out a small brush and some more high pressure spray, and my ramps are SHINY SILVER!  The black I saw was just fouling.

I took some more photos and sent them to Tweak, who believes that there's a good chance that somewhere between the factory and me, my M4 upper got swapped for this.  If that's the case, they still used a C AF marked brand new A3 upper in its place.  And not a parts upper, but one from an assembled factory rifle (proofmark stampings are visible in the upper right photo).  

In the top left of this collage, note how my A2 gray M4 is clearly marked, and the ramps are gray too (anodized after ramps were installed).  On the bottom two are my 6920's ramps, which you can clearly see are silver.    
[img]http://www.boomspeed.com/kisara/ThanksTweak.jpg[/img]
Like I said earlier, two others who purchased the same NIB models with me got the same stuff.  Factory short on parts?  Maybe, but I'd hope likely not.  

The dealer we purchased from has been out of business now for a few years.  

OK, just purchased a new 6920 upper. The upper is marked with a C and a keyhole (Cerro Forge?). It also has M4 stamped abover the gas tube hole. Also has white numbered RAS markings.
Carrier is half circle, unshrouded, marked C with an MPC marked bolt.
Barrel is marked with a production date of 06/03. Barrel extension is marked with a 4.
(Interestingly, my Nov 1991 R6530 upper also is marked with a 4 on the barrel extension and has the M4 feed ramp cuts in the receiver).

I cannot find any serial # on the upper as ColtM4 described. Is it supposed to have one?

Also, there is a white oval shaped marking (paint?)on the bolt and on the barrel (seen where it mates to the upper with handguards removed). What does this signify?

Thanks.

Mick

Made for Colt (C) by [url=http://www.cerrofabricated.com/products_firearm.htm]Cerro Fabricated[/url] (keyhole).



An upper with the M4 ramps requires a barrel with the M4 extension.



The uppers are not serialized.



Dunno. Mebbe a temp mark meaning HS verified or Proof load/Magnafluxed?

[b]kisara[/b],

My previous post must not have survived the server crash.

A source very knowledgeable about Colt's products believes that your ramps were added to an M16A4 upper [b]at the factory[/b]. He sees neatly machined ramps in your photos where I see nicks in the rear of the barrel extension. Your call. [:\]


[bored kode]

I just put the photo back up.  

I've had no problems with the ramps, which I know can cause problems when done incorrectly (remember Coldblue's post about returns from 2nd owners, ugh!).  I took another 1-day class this weekend and pumped 500 more through without a single hiccup.  

Let me know next time you're in SoCal (SoPRK?) or SanFran area and I'll bring it for you to check out.  

Is that a muzzle cap on your carbine ColtM4? Get a lot of rain in your living room? [;)]

It's generally a bad thing to leave those on during storage as they trap moisture in the bore and, more importantly, against and inside of the bolt.

kisara,

The only way that I'm going to Cali is Hannibal Lector-style; shackled to a furniture dolly and escorted by armed guards. [:|]