Ballistic's performance series barrel is machined from 4150 chrome moly vanadium steel with a qpq vorrosion resistant finish.It features a nickel boron coated extended m4 feed ramp extension.The hanson series barrel features a proprietary ba hanson profile and include a pinned lo-pro gas block.This 17.7" barrel is chambered in 5.56 nato, has a mid-length gas system and 1/2x28 tpi threads.Note: hanson barrels are not designed to work with aftermarket piston kits.Caliber Or Gauge: 223 Remington/5.56 NATOLength: 17.70"Model: AR BarrelsTwist: 1:7"Sights: NoneFinish: QPQ Corrosion ResistantType: RifleBarrel Type: BA Hanson MidlengthBarrel Features: Heavy Profile