The TacFire SS-RK300LPK Rifle Kit contains :.300 AAC blackout 7.5" barrel.308 5/8 x 24 TPI spiral fluted flash can w/crusher washerAR15/.750 micro/low profile gas block/mil-spec/steelpistol length gas tube w/pin/steel; ultra slim 7" clamp on MLOK free floating handguardAR15 5.56/.223/.300AAC stripped billet upper receiver w/M4 feed ramps AR15/.556 Mil-Spec charging handle aluminum w/steel latchdust cover; AR15 forward assist; AR15 standard receiver end plateMil-Spec/commercial castle nut/steelAR15 pistol buffer tube w/foam3 oz buffer w/tube springAR15 USA made lower parts kitAR15 standard A2 style black pistol grip