I was looking at a factory Colt LE6920 and noticed that the upper did not have the usual "C" stamped on it near the ejection port and rear sight. It had what I can only describe as some sort of a mishapen triangle. This was on a NIB Colt LE6920 16" M-4.
Is Colt subcontracting these? I seen a picture posted here a while back showing the same mis-shaped triange on the upper.

That is not a mis-shapen triangle, it is a "D" for Diemaco (they make M16s for the Canadian military, and other governments as well as uppers for Colt).  They are the same quality as Colt uppers, I have one of each, they are both outstanding.

Let me guess, the mark looked like a sideways triangle? Yes, that is a "D" for Diemaco. They are the Colt of the Canadian military. Colt licensed them the rights to build M16s. In times of short supply, they have an agree that they will sell their parts to each other when needed.

Since the war in Iraq, Diemaco has been sending their uppers to Colt. They are as good as genuine Colt parts, some say they may even be slightly better. Have no fear, you are getting a quality part from Colt, it just technically isn't produced by Colt.

Just for your own info, Diemaco hammer forged barrels are probably the most coveted AR barrels out there...

Its still just as good as any modern C-AF marked upper.   Grab it before someone else does.

QuickSilver,

I just bought a brand new Colt 6731-my first AR- which also has the Diemaco markings on the M4 upper.  What is it about their barrels that makes them so desirable?  

Combine  that with the information on aonother post about the "Colt Defense" marked lower and maybe this is an exceptionally nice Colt.  

I know I've been very impressed so far, as has everyone else who's handled and shot it.

Thanks for any and all info,
heekma45