The Daniel Defense M4A1 Upper Receiver Group features the M4A1 Rail Interface System (RIS II), which has been in use by US Special Operations Command (SOCOM) for the SOPMOD II Weapons System since 2005. This two-piece, free-floating rail system allows the mounting of devices like a M203 grenade launcher without influencing the barrels harmonics, eliminating problems like wandering point of impact that plagued other mounting designs. The two-piece design also allows for partial disassembly of the rail to aid in cleaning around barrel without completely removing the entire rail system. The weight of anything attached to the RISII rail system is fully supported by a sturdy bolt-up system, using 6 grade 8 bolts, leaving the barrel completely free floating for best possible accuracy and dependability. The M4A1 features a 16” Cold Hammer Forged M4 Profile barrel with a Daniel Defense Improved Flash Suppressor.
This special edition Daniel Defense Upper Receiver Groups include a nitrided mil-spec M16 bolt carrier group and mil-spec charging handle.
The upper receiver has the modest Daniel Defense logo in the upper left of the left side of the receiver. This receiver does NOT have the M4A1 marked logo.