Stag 15 SPR rifle is built around a 18" barrel. It uses an M16 bolt carrier group, Stag 16.5" M-LOK handguard and Magpul furniture. This rifle has an A2 Flash Hider to reduce muzzle flash and a rifle-length gas system, that is combined with a low-profile gas block, which provides reliability under any condition.The free-floating Stag 16.5" M-LOK Handguard features a slim, lightweight profile that offers increased ergonomics, maximum airflow, and modularity while continuing to provide the utmost strength and durability. The handguard also provides an uninterrupted picatinny rail along the top which allows room for sights, optics and accessories the shooter may require. Every complete AR15 from Stag Arms comes with a Transferable Lifetime Warranty and an Infinite Shot Barrel Guarantee.