HK now offers the long awaited civilian variant of the popular 416 upper. This MR556, match grade upper receiver assembly comes complete and ready to pin onto any standard AR-15 lower receiver. The short stroke gas piston design ensures cooler, cleaner operation of this upper for reliabilty and less time scrubbing residue out of the receiver after extended shooting sessions. The flat-top upper receiver and free floating KeyMod rail upper allow plenty of room for mounting sighting devices and any other popular KeyMod accessories the operator chooses. Upper receiver assembly also ships with a carbine length buffer spring and heavy, tungsten filled buffer.
- Upper Receiver: MR556 Flat-Top
- Barrel Length: 16.5"
- Barrel Contour: Heavy
- Barrel Material: Hammer Forged Chrome Moly Steel
- Muzzle Thread Pattern: 1/2"-28
- Chrome Lined: No
- Barrel Finish: Parkerized
- Twist Rate: 1 in 7"
- Chamber: 5.56x45mm NATO
- M4 Feed Ramps: Yes
- Muzzle Device: A2 flash hider
- Gas System Length: Carbine, short stroke gas piston
- Gas Block Diameter: 0.750"
- Handguard: 9" Free Float KeyMod Compatible
- Sights: None
- Bolt Carrier Assembly Included: Yes
- Bolt Carrier Type: Mil-Spec
- Extras: Carbine buffer spring and tungsten filled heavy buffer
Please Note: Installation of AR-15 upper assemblies with certain features including, but not limited to: flash hiders, bayonet lugs, and threaded muzzles may violate state and/or local laws.