Can one of you men that's knowlegable answer this question for me.  I have an upper I bought about 10 years ago (when the gunner's  friend was the pres.) It is stamped on the left side of the upper in letters about a half inch high "Colt 223" (like a Ford tailgate).  The barrel itself has the usual markings, C MP 5.56 NATO HBAR, etc.  It has a screw on A2 cage, with no bayo lug.  I have never seen another marked like this, even the .222 guns I have seen were only marked on the lower.  It has an A2 rear sight too, and of course an F/Ast.  Can you guys tell me anything about it.  By the way, it's so accurate with a scope on it that it even my nephew can shoot subminute groups with it.  Thank you in advance.

I must have the only one ever made, eh..??

Sounds like one of the upper receiver/barrel assemblies Colt sold as a "kit" before the ban,,,,I have seen some of these and all the receivers were stamped with the calibre of the kit,,,,.223 or 7.62,,etc.

They came fully assembled from the factory with carriers and charging handles, as well as conversion pins to adapt to large pin lowers, if my memory is correct.

canters, thanks for the info.  By the way, mine has a small hole, and I put it on a Armalite lower.  Its a beauty.  Just wish I knew more details about it...thanks

I have a post-ban (plain barrel & no lug) with the same markings that you describe.  I bought it new as a complete upper (i.e. kit).  It came from Colt in the smaller "kit" box with 5-round magazines, instructions, and cleaning rod - just like a similar 7.62x39mm upper "kit" I purchased new.

It's a Colt Model 6900DC upper. Colt sold them as upper kits in the Mid 1990's. Price is anywhere from $475-525 depending on shape. Bolt assembly should be the shaved style.

Right-O. I bought one of these new at the time. It came with the complete upper, small hole upper to large hole lower conversion pin, two of the blocked 20 round magazines to make them 5 rounds, and it even included the Accuwedge rubber piece.

I really got hosed on mine.  I paid more for it than the price you indicated, plus it didn't have a bolt/carrier, no book, no pin, no nothing.  Oh well, live an' learn.  At the time, upper were real hard to get at the gun shows, and all were marked sky high here n Michigan.  It was right during that time when ol' Billy boy even wanted to get rid of cammo clothing and ammo boxes....what an asswipe that guy was/is.