Beretta A400 Xtreme KO, Semi-automatic Shotgun, 20 Gauge, 3 Chamber, 28 Barrel, Realtree Max 7 Finish, Synthetic Stock, Right Hand, Fiber Optic Front Sight, Includes 5 Choke Tubes, 2 Rounds J42XS28 The A400 is a gas-operated action that was built for speed, reliability and versatility. The A400 action is self-cleaning, so it requires much less maintenance than any other shotgun you'll ever own. When you take this gun apart you'll be amazed by the intuitive simplicity of the tool-free field-stripping process and by what little maintenance the A400 requires.