Caliber: 5.56 NATO. Barrel: 16.1” chrome lined. Sights: Adjustable. Based on military M4. Direct gas/locking bolt operating system. Magpul MOE handguard, carbine stock, pistol grip, vertical grip. LE6920-FBP2 includes Geissele 13” MK4 rail system and Magpul Pro flip-up front and rear sights. Add 10% for the Magpul variant and 40% for the FBP variant. SEE POLITICAL PANIC PRICING.