Ballistic Adv BABL556013F Performance Series 223 Remington/5.56 NATO 16" QPQ Corrosion Resistant This Ballistic Advantage Performance Series Barrel is machined from 4150 Chrome Moly Vanadium steel with a QPQ corrosion resistant finish. The barrel features a FailZero Nickel Boron coated extended M4 feed ramp extension.