Hello
I have one complete sp1 upper and one sp1 barrel.  I was wondering what you guys can tell me about them and when they were made and possible by who.
Thanks

Barrel is marked C MP CHROME BORE Front Stight is Marked C and barrel has a bird cage style flash hider  I am thinking Colt what any ideas on manafacture date or more info?

I also have a complete sp1 upper.  No marking on upper reciever at all,  no markings on front sight marked M on barrel under font sight and has a diamond type stamp with something in the diamond.  Also marked 12 on underside of barrel.  Has a three prong flash hider.  

Any idas guys
Thanks again

well, SP1 is a Colt trademark.  the "C" in C MP stands for Colt, C on the front sight block stands for Colt.
I'm pretty sure what you got there is Colt.  Not sure on the date, I don't think there's a way to tell, SP1s are made till the 80's if I remember right.

I don't know about your complete SP1, the little diamond thingy is probably the Colt proofstamp, is it located near the front of the dust cover?

The 12 stands for 1 in 12 twist rate, if the three prong is original, it's a old one, probably late 60s.

There is not marks on the upper receiver at all.  The diamond markd in next to the M on the barrel under the front sight.  

The barrel only is a later version; made sometime between about 1974 and the end of SP1 production.

The barrelled upper is a very early job, probably from the 1960's.  The totally unmarked upper would be an indicator, since Colt didn't start putting the C and forge letter under the rear sight until after the the services adopted the M16, and they had to start using more than one forge for their blanks. While the first barrel is chrome lined, the early one is not.