Product Description The Daniel Defense DD BBL 556 18" S2W Rifle Barrel is a precision-engineered replacement barrel built to meet and exceed military specifications. Chambered in 5.56mm NATO with a 1:7 twist rate, this barrel features a rifle-length gas system and the S2W Heavy Barrel Profile in a matte black finish. Cold-hammer forged from 4150 Chrome Moly Vanadium (CMV) steel, it incorporates a mil-spec heavy phosphate coating and a chrome-lined bore for outstanding durability, corrosion resistance, and long-term accuracy. Designed as a direct replacement or upgrade for AR-platform builds, this barrel reflects the same quality Daniel Defense installs on its factory rifles and is trusted by military personnel, law enforcement, and serious shooters alike. Product Highlights Cold-hammer forged from 4150 Chrome Moly Vanadium (CMV) steel for exceptional strength and service life Mil-spec heavy phosphate coating delivers superior corrosion resistance and a durable matte black finish Chrome-lined bore enhances wear resistance, simplifies cleaning, and extends barrel longevity Rifle-length gas system promotes smoother cycling, reduced felt recoil, and more consistent performance S2W Heavy Barrel Profile with 1:7 twist rate optimized for 5.56mm NATO ammunition and accuracy at extended range Specs Brand: Daniel Defense Caliber: 5.56mm NATO Barrel Length: 18" Twist Rate: 1:7 Gas System: Rifle-Length Barrel Profile: S2W Heavy Material: 4150 Chrome Moly Vanadium (CMV) Steel Finish: Matte Black / Mil-Spec Heavy Phosphate Coating Bore Lining: Chrome Lined Color: Black MPN: 07-116-05042-018 UPC: 815604019187 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.