Springfield Armory Hellion 5.56mm NATO 16in Black Melonite Semi Automatic Modern Sporting Rifle - 10+1 Rounds - The new Hellion from Springfield Armory represents a radically unique and innovative approach to firearms design, helping to redefine perceptions of semi-automatic 5.56mm performance. Featuring a "bullpup" configuration where the action is located behind the trigger, the Hellion features an overall length of just 28.25-inches while still possessing a 16in barrel. The Hellion sports ambidextrous controls that work in concert with a reversible case ejection system. The result is a 5.56 that combines portability with potent performance.