Material Lowers and Uppers are CNC Machined from 7075-T6 Aluminum Forging - Barrel Length 16in - Twist rate 1:7 - Rail Length BM U-Rail 15 Rail - Diameter of the Handrail 1.35in - Threading x 28 - Mil-Spec Mil-Spec Trigger 5.56 BCG and Ambi Charging Handle - Magazine 30 rd Magazine - Stock Standard Adjustable Stock - Buffer weight 3oz Buffer - Weight 6.29 lb - Length 31.5 Stock Not Extended - Weapon system Semi-Auto and Gas Impingement System - Color Cerakote Finish Tungsten