CMMG Upper MK4 PDW 300 AAC Blackout 8" 1:7 M16 Bolt Group, RKM 7" KeyMod Handguard, Low Profile Gas Block, Black 30B8188 Out of stock. Check back later... $749.95 MSRP Price: $681.00 Notify me when this item is back in stock (log in required) Description Details Reviews Shipping info M16 Bolt Group UPC: 815835012032Manufacturer: CMMGModel: 30B8188Caliber: 300 AAC BlackoutCategory: PartsOtherUpper receiverStock: 0Unit/Measure: ea This item may be shipped directly to your home address, unless you live in a restricted state.