Looking for a foundation for a M4A1 Block II build? Look no further, Brownells has put together a few items to help you make the decision! The Daniel Defense M4A1 SOCOM Block Upper Receiver, B5 Government Issue SOPMOD Stock, and the Tan Eotech XPS3-0. The Daniel Defense M4A1 SOCOM Block II Upper Receiver has been designed for those looking to match the specs and performance on the M4A1 SOCOM Block II carbines used by troops during Operations Iraqi Freedom and Enduring Freedom. The Daniel Defense M4A1 SOCOM Block II Upper Receiver features a quad-rail handguard equipped with a Picatinny-compatible rail sections. The barrel is cold hammer forged from mil-spec chrome-moly vanadium Mfg: Brownells