Aero Precision 18" .223 Wylde SPR 416R Stainless Steel Nitride Rifle 1: 8 AR-15 Barrel - $139.95 Our .223 Wylde barrels have been HP/MPI tested and are machined from 416 Stainless Steel. The barrels feature Nickel Boron-coated M4 feed ramp extensions and have a QPQ corrosion-resistant finish. The