amateurarmsdealerSelling a used HK MR556A1 upper. This is the original HK upper receiver and 16.5" nitride barrel with HK's short-stroke gas piston system. It's been fitted with a Geissele HK416 Super Modular Rail (Geissele blem unit, fully functional, cosmetic only) and runs a Brownells BRN-4 bolt carrier group in place of the HK BCG. What you're getting: HK MR556A1 upper receiver and barrel assembly Geissele HK416 Super Modular Rail (blem) Brownells BRN-4 bolt carrier group OEM Charging handle OEM Barrel Condition: Used, and priced accordingly. Finish shows honest wear from use with handling marks on the receiver and rail.
