Doublestar R102: This incredible carbine from Doublestar includes everything you need in a reliable rifle and nothing you don't. This model features a fixed front sight and 16" 1:9 twist 5.56 barrel. Also featured on this model is a matched forged upper and lower receiver set. An adjustable stock comes standard on this model with a traditional pistol grip and handguards. With all of these options, the DS4 is the perfect gateway carbine, ideal for entry-level AR-15 enthusiasts and die-hard devotees of the M-4. The DS4 is DoubleStar’s take on the most trusted battlefield carbine in existence and available at an affordable cost.