I just got a colt sp1 kit. Complete upper. It was dropped off with my brother inlaw I need to drive out and get it. This weekend maybe
I would like to know more information about it. C on the bcg C M on the upper under the rear sight. What I am curious about is the raw ch and years of production. From the little I know about these is the cm was early to mid 70s . I don't understand why it has no forward assist. It looks like a 601 or 602 upper but, cm was used only in the mid 70s. Is this possibly an earlier upper? It is a large pin upper. My plan for this was a RRA mid length SS barreland dpms free float tube. Then to see if I could get an a2 rear sight knob on it. I don't want to take it apart if it has any historical significance. My brother in law said the rifling is amazing. Just dust. Unknown barrel twist. I would guess 1 in 12
Any help would be appreciated.