Bcm m4 carbine mod-0 5.56 nato 16" keymod black FEATURES:Caliber: .223 Remington/5.56 NatoTwist: 1:7"Barrel Length: 16"Magazine Capacity: 30 roundsOverall Length: 32.5"Weight: 6.3lbs.Action: Semi-Automatic Other Features: Bcm pkmr handguard, bcm gunfighter charging handle bcm mod 0 compensator, bcm buttstock, bcn mod 3 pistol grip bcm qd end plate, bcm pnt trigger, bcm trigger guard