The Executive Order (XO) is a lightweight, accurate, hard hitting carbine. Available only with a 20-inch Proof Research barrel, you can choose between .308, .260 Remington, and 6.5 Creedmoor chambering to fit your shooting needs. The longer barrel ensures that you can extract maximum velocity from your projectiles. Ambidextrous controls make operating the XO a cinch for any shooter. Additional features include a 15, 6061 M-LOK modular rail, NEMO dual chamber compact muzzle brake, Quick switch .875 journal gas block with Suppressed and Unsuppressed settings, Titanium takedown and pivot pins, Ambidextrous safety selector, Ambidextrous charging handle, Mil-Spec forward assist, Sling compatible latch plate and properly staked castle nut, Geissele SD-E two stage trigger, Magpul MIAD grip, Magpul CTR stock, recoil reducing bolt carrier and nickel boron coated bolt.