I know that Aloca Forge makes the Raw Forgeing's and sell's them to Colt and CMT . I know some of the marks like the Keyhole , ''C'' , '' A'', AF and the Cardinal. But, I still need help to I.D. all of them and to tell which are Colt and CMT. I am thinking doing a SOCOM upper build annnd trying to get the upper right.

the only way i could tell was my colt had an "M4" stamped on the outside just above my gas tube ( i needed a good light to see it). my CMT does not.  not at all inclusive, just my .02.

The old CMT M4 uppers had the M4 stamped above the gas tube hole

My CMT upper has "M4" stamped above the gas tube hole as well but it also has the "C" marked inside the reciever.  

Do the Colt uppers also have the "C" marking?

what would it matter?


as long as the ramps line up and it fits good why would it matter who finished it? you could buy 3 cmt's for what i have seen people ask for "colt m4" uppers.

I can think of one clue, Colt's added a bevel to the front pivot pin lug on their uppers starting in 1963.  From what I have seen most other makers skip that machining step.

That last few Colt's stripped uppers I got from Brownell's appear to be just some stuff Colt's bought from someone vender and sold at a big mark up.  They did not even have any maker codes on them, no "T" markings, one did not even have the hole drilled for the ejection port door.  Come to think of it, wonder if they even had the bevel machined on the front lug?

ETA:

Still had the picture on photobucket.com of the upper I got from Brownells that did not have the ejection port door rod hole drilled.  You can see that it does have the bevel on the front pivot pin lug: