Radical Firearms AR-Pistol 556/223 FCR is a fully Mil-Spec AR-15 pistol built using their law enforcement grade upper receivers and mil spec lowers.This pistol provides High Quality features at an affordable price & shoots BOTH .556 and .223. The 4150 Chromoly Vanadium Steel barrels are Melonite treated for a harder-than chrome finish without chrome's accuracy robbing side effects! This same finish is applied to the bolt carrier groups, helping to reduce receiver wear and increase reliability. The bolt heads are MIL-STD and MPI for quality assurance. The free float hand guard keeps your hands cool and provides plenty of room for accessories. As an added touch, we are adding a Radical Firearms FCR Free float hadnguard that we built from scratch in-house! The FCR rail even has the capability to add attachments other than on the top picatinny rail, as it does allow Magpul M-LOK attachments and rail sectionsRadical has been able to combine all of these features in a great package that a working man can afford all backed up by a lifetime warranty.