Group. I ran across this upper half, and it left me with some questions/concerns. It appears to be all Colt, or nearly so. My more recent Colt uppers have a stamped "C" in the upper, where this one is raised as is the forge ID. Barrel is dated 08/09, and am wondering if the receiver might be from the same timeframe. I have no idea whether this was assembled at Colt, or if it was assembled out of a parts bin. Any insight on whether the receiver is of the same vintage as the barrel would be appreciated.

My late 2008 colt came with a stamped C receiver & cerro forge code

This doesn’t mean that colt didn’t have some old raised C receivers still laying around.
It’s colt.. nothing is 100% sure with them

I don’t remember when Bafe receiver were introduced.. Tig and other will have more accurate info.

Typical of '03-'05 receivers from what I've seen personally. Stamped C came about in '06 (?)

Odd that it is BAFE marked, typically it would be Cerro Forge.....but it's Colt, and nothing is a definite or consistent.

As stated, Colt seems to pull parts from the nowhere many times in order to build guns.

Raised C and square forge is something I’ve seen on newer production uppers...

Interesting, recall where you saw them?

Raised C & Raised Square Brass forge ?  I've never seen a Raised C & a Raised Square Brass forge marking but like Tig said nothing is consistent with Colt. All the Raised C markings I know of are on Anchor Harvey & AF marked receivers...

Attached File

I’ve always seen the Bafe forging with the stamped C or the cage code.

Any dry film lube sign inside the receiver?

Yes. Inside is coated with gray dry film lubricant. Upper appears to be unused with only a trace of wear in the charging handle track.

My other Colt uppers with BAFE forge mark have the stamped C which is what threw me off on this one.

Seems like there is enough uncertainty about what occurred at Colt, that inquiring WHY is best avoided entirely.

I have seen Colt from 1993 to present, and you get all sorts of combinations.  The only thing in common is the move away from C to CAGE Code somewhere around 2018

From what I recall looking at lots of the .mil program gunn pics, the C AF forgemark was pretty much the main one up until the mid 00s, after that started seeing Colt "Keyhole", then later down the road the square forgings started showing up. But up through like 2003-2005 you'd see mostly the AF forge marks. Keyhole seems to come in 2005-2008 or so.

My references are mainly digging through Mk12s, M4A1s, Mk18s, etc from those time periods. Most Mk12s were built up through 2004 but some 2005/2006 were done from what I understand, and that SMGLee dude has a photo of a real Mk12 Mod 1 with a Colt Keyhole forgemark upper, so that could have been 2005/2006 production. Also have a photo of the "Mod H" guns that started being slapped together in 2007, one of the prototypes was a Colt Keyhole, and other were on plain keyhole forge uppers. I think Square started showing up after that, like 2010 maybe? I remember seeing a lot of square forge on the market around then when I started building stuff.

I think the Cerro Keyhole change was a little earlier than that. Two of my Army issued M4s that I have serial numbers and photos of both had raised C / Cerro Keyhole uppers. One was produced in 2003 (the one Tigwelder posted a photo of above) and the other was built in 2004, according to the Colt Archives.

^^^^^ Been racking my brain trying to remember whose pic that was....

Good to know, I'll file that away in the brain bank. I hadn't seen anything showing them that early but naturally my focus has been more narrow.

I saw rather recently a replacement upper receiver new in the wrapper with a Colt cage code on the wrapper it had a stamped "C" and a keyhole forge mark: The sticker on the wrapper had a 2002 date on it. It seems as though Colt just bought batches from whomever whenever possible: The plot thickens.