Diamondback DB15 5.56/.223 Rifle with Romeo 5 Optic : Manufacturer: Diamondback Firearms Model: DB15 Type: Semi-automatic rifle Caliber: 5.56 NATO / .223 Remington Action: Direct impingement, gas-operated Barrel Length: 16 inches Muzzle Device: A2-style flash hider (1/2x28 thread) Handguard: Free-floating M-LOK rail (length varies by configuration) Upper Receiver: Flat-top, forged 7075-T6 aluminum with Picatinny rail Lower Receiver: Forged 7075-T6 aluminum, hard coat anodized Bolt Carrier Group: M16 profile, MPI tested, phosphate finish Trigger: Mil-Spec single-stage Optic Included: Sig Sauer ROMEO5 red dot sight (2 MOA, MOTAC, 50,000 hr battery life) Stock: 6-position adjustable polymer stock Grip: A2 or Magpul-style polymer grip (varies by model) Finish: Type III hard coat anodized black Capacity: Standard 30-round magazine (STANAG compatible)