HK MR556, MR223 Upper Receiver - Forward Assist and Ejection Door

New HK German Partially Pre-Assembled Upper Receiver for HK MR556 and HK MR223

Each unit comes just as shown with the F/A (forward assist) assembly and ejection port door assembly installed from the HK factory. 

Compatible With:

• MR556
• MR223
• HK416***

Need a matching lower for your build?  STS416 A5 LOWER - Specialized Tactical Systems

***Although this MR556 receiver is compatible with 416 lowers, the HK416 bolt carrier group is not compatible with the MR556 upper receiver without modification to the upper receiver.  To pair this MR556 upper to a 416 lower without modification to the MR556 upper receiver, use the MR556 semi-auto bolt carrier group.***