The Geissele Automatics Border Patrol AR-15 Rifle is a lightweight and dependable 5.56x45mm NATO chambered AR-15 designed for service use. It features a 16" Geissele cold hammer-forged (CHF) chrome-lined barrel with a 1:7 twist rate. It has a Geissele-length gas system with a Super Compact Gas Block. The upper and lower receivers are Super Duty components, forged from 7075-T6 aluminum and hard-coat anodized. The 14.6" MK 20 Super Modular Rail is skeletonized for weight reduction and features M-Lok slots for accessory mounting. Chambered in 5.56 NATO 16" Geissele CHF chrome-lined barrel, 1:7 twist Geissele-length gas system with Super Compact Gas Block Upper/Lower receiver: Super Duty Mil-Spec forged 7075 T6 aluminum, hard-coat anodized 14.6" MK20 Super Modular Rail with M-Lok slots at 3, 6, and 9 o'clock Geissele Government ambidextrous charging handle