Criterion Barrels Hybrid AR-15 Barrel in 223 Wylde, 18 rifle-length, chrome-lined bore, 1:8 twist. The Hybrid contour provides a balance of weight and material for excellent heat absorption and consistent harmonics. Chrome-lined bore enhances durability and simplifies cleaning. Designed for AR-15 platforms and performance applications requiring reliability under high rates of fire. Headspace should be checked for optimal performance and reliability.