I will start off by saying I have little knowledge of what I am selling. Anyone with more "helpful" information, please post what you have. What I think I have is a Colt 603/604 M16A1 vintage 1966-1969 upper with a semi-auto BCG and charging handle. Barrel is marked MP. Upper Receiver is marked C in a square and VP in a triangle. A1 type triangular forward assits. Small hole receiver. What you see is what you get. I am asking $650.00 cash. If I am out of line on price please let me know.