Everyone loses their shorts over HK not featuring a chrome lined barrel on the MR series rifles. As discussed previously on HKPro the barrels are sent from Germany already as cold hammer forged and nitrided 'blanks'. Daniel Defense profiles the blanks (removing outer layer of nitride treatment) and adds a parkerized treatment to the exterior. Since the nitrided surface would have been present on the outer and bore surface before profiling and in the bore after, that offers something rather unique. Chrome lining is cheaper than nitrocarburizing (nitriding) and has an inherent impact on accuracy as chrome cannot be applied perfectly. Nitriding has no impact on the bore so it's as sharp as when the mandrel made it. Considering HK uses something in the area of 4340/4350 alloy steel for their barrels, this is already a harder steel than typical chrome moly alloy used in U.S. MILSPEC M4/AR-15 barrels, add to that the nitrocarburizing and you have a superior barrel. While I understand the value of chrome lining, the lack of it is often used to criticize the MR barrels in an area that traditional AR-15 barrels are already deficient.