Radical Firearms FP75556M47RPR: The Radical Firearms complete AR-Pistol is a fully Mil-Spec AR-15 pistol built using law enforcement grade upper receivers and mil spec lowers. The 4140 chromoly vanadium steel barrel is Melonite treated for a harder-than chrome finish. 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 full-length, free-float handguard keeps your hands cool and provides plenty of room for accessories. This model has a 7.5\" barrel, Radical Firearms 7\" RPR handguard with Magpul M-LOK slots on sides and bottom of the rail.