Radical Firearms complete AR-Rifle is a fully Mil-Spec AR-15 rifle built using enforcement grade upper receivers and mil spec lowers. The 4150 Chromoly Vanadium Steel barrel is Melonite treated for a harder-than chrome finish. The same finish is applied to the bolt carrier groups, helping to reduce receiver wear and increase reliability. Its bolt heads are MIL-STD and MPI for quality assurance. The full-length, free float handguard keeps your hands cool and provides plenty of room for accessories. It comes with a 12" FGS (Forward Guard Shield) Round Rail that has the capability to add attachments other than on the top picatinny rail, as it does allow Magpul Moe attachments and rail sections.