Stoeger M3020 Realtree MAX 7 20 Gauge 2-3/4in Semi Automatic Shotgun - 28in. The M3020 3-inch chambered, 20-gauge, Inertia Driven semi-automatic shotgun joins Stoeger's line of high-quality, affordable firearms. Versatility, value and solid reliability make the M3020 ideal for waterfowl, wild turkey, or upland game. The M3020 handles a full range of loads, from 2 3/4-inch up to the potent 3-inch magnum without adjustment. For reliability and performance, no other 20-ga. semi-auto in its price range compares.