This is a large hole Colt SP1 upper, with a colt mpc marked bolt, c marked carrier with forward assist grooves and 20"pencil barrel marked mpc b. The b means chrome bore, I think. (not an AR barrel expert)
It comes with a large hole to small hole lower adapter pin, so it will work with all lowers.
The receiver has initials and a ssn marked onto it, right behind the ejection port. The receiver has a bit of wear, Near the barrel on the right side are two forge marks; a faint circle in a square symbol, and an even fainter triangle.
Its a nice shooter, pretty accurate, and no issues with this upper on my rra lower.
Buyer can choose either type of handguards shown.
I have more pics available, dont hesitate to ask.$350
complete with the bolt/carrier/charging handle
without the bolt/carrier/charging handle .
Not looking to part out, so dont call dibs on stuff.
I take MO's or paypal +3%
Buyer pays $10 shipping via UPS.SPF