ok, i haven't delt with colt parts much.  i took this upper receiver in on trade this weekend and the guy told me it is a colt M16 receiver.  i just wanted to ask here to be sure.  the P and M are the only marks on the receiver and the finish does look like colt.  does anyone know for sure?

bump for the weekend.  SOMEBODY has to know if it's authentic colt or not.

www.biggerhammer.net/ar15/uppers/

I did not see it on the list

If it was Colt, it would have a "C" as one of the markings Might be a GI contract replacement unit, or an early aftermarket (Bushmaster?) piece.

The M should stand for Martin Marietta, the P would be whom Martin Marietta did the forging for, and in this case I have no idea.  Never heard of a USGI PM forge code.  Does your windage drum have numbers on it?  Looks blank.

PWA????

Quoted: The M should stand for Martin Marietta, the P would be whom Martin Marietta did the forging for, and in this case I have no idea.  Never heard of a USGI PM forge code.  Does your windage drum have numbers on it?  Looks blank.

yea, it has the numbers on it.  my camera just doesn't take good close-up pictures.  and the finish is dark black, not gray like it looks in the photo.

the guy traded the upper, a 3-point sling, a colt M-16 bolt carrier (yes, stamping on the carrier are colt) and a box of misc M-16 parts.  (hammers, disconectors, selectors, delta rings, etc... no sear though.)   i don't know where he got them and i didn't ask.  

so i do believe the upper is an M-16 take-off.  

thanks guys,  i was just wondering about the marks.

I have seen a lot of A1 upper receivers with the P M forging mark.  I don't know who made them, but they all seemed to be good quality upper receivers.