CMMG MK4T SBN Upper, Fits AR, 223 Rem/556NATO, 16" Barrel, A2 Brake, Flat Top, CMMG RKM11 KeyMod Handguard, Black 55BC76A Out of stock. Check back later... $699.95 MSRP Price: $659.00 Notify me when this item is back in stock (log in required) Description Details Reviews Shipping info Flat Top UPC: 815835015866Manufacturer: CMMGModel: 55BC76ACaliber: 223 RemCategory: PartsOtherUpper receiverStock: 0Unit/Measure: ea This item may be shipped directly to your home address, unless you live in a restricted state.