CALIBER: 5.56 NATO - BARREL: 16.1 (40.9cm) - WEIGHT: 7.3 lbs (3.31kg) - MUZZLE THREADS: 1/2x28 TPI - RIFLING: 1:7 RH - LWRCI manufactured barrel is precisely torqued in our factory to a consistent torque setting cold hammer forged- Nicorr treated with a 1:7 twist stabilizes a wide range of bullet types - All LWRCI forgings are coined: the material is struck twice in the die for precise dimensional accuracy and a superior surface finish - MagpulA(R) MOE+A(R) Grip combines reinforced polymer body construction with comfortable wrap-around rubber overmolding for maximum weapon control in adverse environments