ONE HORSE LLC 5.56 NATO M4 CONTOUR CARBINE BARREL FOR AR-15 16a ^2 M4 Contour Barrel - 5.56 NATO, 1:7 Twist, Nitride Finish Build a reliable and accurate AR15 with this 16a ^2 M4 Contour Barrel. Chambered in 5.56 NATO with a 1:7 twist rate, this barrel stabilizes a wide range of bullet weights for exceptional versatility in tactical or range applications. Its carbine-length gas system ensures smooth cycling, while the premium nitride finish enhances durability, corrosion resistance, and reduces maintenance. Precision-crafted to Mil-Spec standards, it's the perfect choice for your next build. 16a ^2 length with M4 contour for balanced weig Mfg: One Horse