MR556 Upper Receiver Kit
- Complete MR556 Upper Receiver/Barrel Assembly— HK 16.5 inch cold-hammer forged barrel, upper receiver with forward assist, extended convertible charging handle, HK Free Floating Rail System handguard
- Complete MR556 Bolt Group Assembly
- Tungsten Filled HK Proprietary Buffer
- HK Proprietary Buffer (Action) Spring
- NOTE: The MR556A1 Upper Receiver Kit is not classified as a firearm and can be purchased without a Federal Firearms License ( FFL).
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