HK MR556 Upper receiver to HK416 10.4in configuration.
Allows most AR-syle rifles (retractable stock models only) to be retrofitted to the same pusher rod system used in the MR556A1 and HK416. Includes complete MR556A1 Upper Receiver/Barrel Assembly with HK 10.4 inch cold-hammer forged barrel, upper receiver with forward assist, extended convertible charging handle, HK Free Floating Rail System handguard, HK Bolt Group Assembly, HK Proprietary Buffer, and HK Buffer (Action) Spring.
***Picture may vary on rail system based on production |