Description from CMMG's website
16" M10 Mid-Length MedCon upper. This upper is built around the M10 multi-role barrel with mid-length gas, mid-length handguards, mid-length sight radius and is complete with bolt, carrier and charging handle. CMMG semi auto bolt carriers have the shrouded firing pin to protect against hammer wear. Upper receivers are "T" marked and include extended feed ramp cuts. Features include medium contour barrel, 11 degree recessed target crown, chrome-lined 5.56mm chamber and bore, 1/7 twist, parkerizing under “F” marked forged front sight base and magnetic particle testing on every barrel. When ordering with optional gas block, barrels will not be drilled for taper pins. Barrel is marked CMMG MPC 5.56 NATO 1/7.
This one has the F marked FSB, extended and polished feed ramps, and is complete with B,BC,CH. I cleaned the upper and mounted it on a lower but I never had a chance to fire it so I call it like new in box. $500 shipped. USPS money orders only. e-mail for pics