The Daniel Defense MK18 Upper Receiver Assembly is a factory-built complete upper chambered in 5.56mm NATO, featuring the authentic RIS II (Rail Interface System II) handguard in Flat Dark Earth.
- Type: Complete AR-15 Upper Receiver Assembly
- Caliber: 5.56mm NATO
- Barrel Length: 10.3 inches
- Barrel Profile: Cold hammer forged, chrome-lined
- Gas System: Mid-length, pinned low-profile gas block
- Handguard: Daniel Defense RIS II, Flat Dark Earth
- Rail: MIL-STD-1913 Picatinny
- Finish: Flat Dark Earth
- Receiver Material: Forged 7075-T6 aluminum
- Compatibility: MIL-SPEC AR-15 lower receivers
- NFA Notice: Attaching this upper to a rifle lower creates an SBR requiring ATF Form 1 or Form 4 approval
