Kel-Tec SU16E 223 Remington 16in Black Semi Automatic Modern Sporting Rifle - 10+1 Rounds - The SU16 series is designed, engineered and crafted to be the perfect everyday Sport Utility rifle. Differing primarily in barrel length and stock configuration, these gas piston operated, semi-auto rifles accept standard AR-15 magazines, with some models that store two spare, proprietary magazines in the stock.