CMMG Mk4 AR-15 Upper Assembly 5.56mm 55B9C21

CMMG, Inc.
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CMMG AR-15 Upper Group, Mk4, 5.56mm

The Mk4 is where it all started at CMMG. The 14.5" chrome lined barrel is built to the exact same specifications as the barrels used in the militarys M4 carbines. The extended A2 compensator is permanently attached in order to meet the legal minimum length requirements. Like all CMMG products it features our lifetime quality guarantee.

Features and Specifications:
Manufacturer Number: 55B9C21
Caliber: 5.56mm
Barrel: 14.5", 16" with Permanently Attached Extended A2 Compensator, 1:7 twist, M4 profile, 4150 CMV CL, phosphate finish
Muzzle: Extended A2 compensator, permanently attached, threaded 1/2-28
Hand Guard: M4 type 2 piece hand guards
Receiver: Forged 7075-T6 AL M4 type upper
Gas Port Location: Carbine