The AR-STONER AR-15 Barrel 458 SOCOM Barrel provides high performance and accuracy for the 458 SOCOM round. Manufactured from 4150 Chrome Moly Steel, this 1:14 twist, 16" heavy contour barrel provides high quality at a great value. Features include a carbine-length gas system, M4 feed ramps, and a 5/8-32 threaded muzzle. The barrel extension and locator pin are included and installed at the factory.