The vk-1 rifle uses a patented low-profile piston system design featuring optimum gas port sizing and an advanced piston assembly.This features a unique cup and spigot design that improves the gas seal and overall efficiency of the gas system.The vk-1 includes a staged gas bleed system that allows the rifle to operate consistently, either suppressed or unsuppressed, with varying types of factory ammo.The vk-1 short stroke piston system includes a fully-supported one-piece op rod and removable gas block which matches the footprint and weight of a standard di ar-15 while providing the benefits of a piston driven system.Includes one california compliant compmag, rifle lock and hard caseCaliber: 5.56mmBarrel Length: 16"Capacity: 10+1Trigger: Hiperfire Single StageOal: 31.90"-34.50"Weight: 6.80 lbsStock Description: Magpul SLMuzzle: A2 Flash HiderSights: None, OpticReadyBarrel Description: SteelTwist: 1:7"Barrel Length Range: 16" to 16.99"Weight Range: 6 lbs to 6.99 lbsHand: AmbidextrousStock Finish Group: BlackMetal Finish Group: Blued/Black