Faxon Firearms Duty Series, 1:10 Twist Barrel, 4.02, 9MM, Fits Glock 19, Gen 2-5, Nitride Finish, Black GA910N19NGQ-N Faxon's Duty Series Pistol Barrels for G19 / Glock 19 are machined 100 percent in-house from stress-relieved 4150 CMV steel. These barrels are then given a black Nitride coating to increase lubricity" barrel life" and resistance to surface wear. All barrels are conventionally rifled to allow a wider range of ammunition to be used" including cast lead. The barrels drop into factory-spec slides with no gunsmithing required. Better-than-factory tolerances ensure a consistent" tighter lockup than OEM.