Heckler and Koch MR556 A4 5.56 NATO 11" Complete Upper

Description: Heckler and Koch MR556 A4 5.56 NATO 11" Complete Upper. The MR556 upper receiver kit has been updated to include all the new A4 features, including the new barrel profile, adjustable gas block, handguard, and more. This kit includes a complete upper receiver/barrel assembly, allowing Mil-Spec 5.56mm AR-style rifles to be retrofitted to HK's piston and pusher rod system. The MR556 A4 is assembled in the USA using US and German-made components. It functions reliably and shoots accurately with a wide variety of quality 5.56mm or .223 ammunition.

Features:

• Complete MR556 upper receiver/barrel assembly. Barrel, upper receiver with forward assist, extended charging handle, and free-floating slimline handguard.
• Complete MR556 bolt group assembly
• Tungsten Filled HK Proprietary Buffer
• HK Proprietary Buffer (Action) Spring
• Adjustable Gas Block
• Ships in HK Soft rifle case.

Note: Due to the shortened length of the HK buffer and action spring, these parts do not work in fixed-stock AR/M16 - type rifles. Installation of Mil-Spec hammers on non-HK lower receivers is required for reliable function. All NFA/ATF Rules Apply! Installing this receiver on a non SBR (Short Barrel Rifle) will require you to register the rifle per NFA regulations.

Manufacturer: Heckler and Koch

PRODUCT SPECIFICATIONS:

• Barrel Length: 11"
• Barrel Thread Pitch: 1/2" x 28 TPI
• Brand: Heckler and Koch
• Caliber: 5.56x45mm,.223 Rem
• Finish / Color: Black
• Firearm Type: Rifle
• Material: Aluminum,Steel
• Models Fit: HK MR556