The HK 416 series rifle was designed for U.S. special forces as an alternative to the M-16 variant standard issue weapons. The 416 D145RS in .22 LR is manufactured exclusively by Walther under license from HK, making it the only genuine HK tactical rimfire replica available in the world. Every 416 D145RS features a quad rail forend, a retractable buttstock with a storage compartment, and a Rail Interface System with a full-length picatinny top rail for scope and sight mounts and a picatinny quad-rail forend for accessories. The rifle comes with a set of sights made up of a front post with two interchangeable options included and a rear sight that's adjustable for both windage and elevation. The upper and lower receivers are solid metal with a functional dust cover and bolt catch. The 416's muzzle is threaded and its pistol grip has a storage compartment. 1 in 13-3/4" twist. M8x.75mm muzzle thread.