This.308 chambered (dpms style) 18 inch barrel is machined from 416r stainless steel with a qpq corrosive resistant finish.Our premium series barrels are hp and mpi tested, ensuring the best quality and accuracy.Hanson series barrels feature our proprietary ba hanson profile, including a pinned lo-pro gas block.Hanson barrels are not designed to work with aftermarket piston kits.Length: 16"Model: Premium SeriesTwist: 1:10"Finish: QPQBarrel Type: BA Hanson MidlengthBarrel Features: Ops 12