M4 Style Standard Big Bore Upper Receiver – Right Handed


Receiver Modification – You must buy a barrel to select this option


Ejection port enlarged, includes forward assist and ejection port cover.  Made from 6061 aluminum.

*Tech Tip: To enhance feeding reliability with blunt nose bullets, it is recommended to blend the barrel feed ramp into the upper receiver after barrel installation, as shown. (Warning: DO NOT Modify the steel locking lugs on barrel extension.)

Weight:  8.5oz