Product DescriptionThe Ballistic Advantage Performance Series BA Hanson barrel is built for dependable AR-15 performance with a durable 4150 chrome moly vanadium steel construction and a corrosion-resistant black QPQ finish. This 17.7-inch barrel is chambered in 5.56 NATO and uses a mid-length gas system to help promote smooth, reliable cycling. Designed around the proprietary BA Hanson profile, it also features a nickel boron-coated extended M4 feed ramp extension for consistent feeding, and it includes a pinned low-profile gas block. Note: Hanson barrels are not designed to work with aftermarket piston kits.Product Highlights Performance Series AR-15 barrel machined from 4150 chrome moly vanadium (CMV) steel for long-lasting strength Black QPQ corrosion-resistant finish for enhanced wear and environmental protection Nickel boron-coated extended M4 feed ramp extension helps support smooth, reliable feeding Proprietary BA Hanson heavy profile with pinned low-profile gas block for a secure gas system setup 5.56 NATO chamber with mid-length gas system and 1/2x28 muzzle threads for common muzzle device compatibilitySpecs Brand: Ballistic Adv Manufacturer Part Number: BABL556018F UPC: 819747020772 Caliber: 5.56x45mm NATO (also compatible with .223 Remington per retailer listing) Barrel Length: 17.7 in Material: 4150 Chrome Moly Vanadium Steel Finish: Black QPQ Profile: BA Hanson (Heavy Profile) Gas System Length: Mid-Length Twist Rate: 1:7 Muzzle Threads: 1/2x28 TPI Approvals/Testing: HP and MPI Tested Listed Weight: 31 oz Gas Block Journal (retailer listed): 1.03 in gas block seat (for 3/4 in low profile gas blocks only)Disclaimer: We strive to provide accurate and up-to-date product descriptions, specifications, and images; however, errors or omissions may occasionally occur. We are not responsible for any inaccuracies or discrepancies in the content provided. If you notice anything incorrect or unclear, please contact us so we can correct it. When in doubt, we recommend verifying details directly with the product's manufacturer.