Mossberg 940 Pro, Field, Semi-automatic Shotgun, 12 Gauge 3, 28 Vent Rib Barrel, Matte Finish, Blued Barrel/Receiver, Accu-Set Choke Tubes, Black Synthetic Stock, Fiber Optic Front Sight, 4 Rounds 85155 Inside the Mossberg 940 Pro shotgun, you will find a durable gas system that allows for up to 1500 rounds between cleanings, and a host of corrosion-resistant internal parts/finishing (nickel boron-coated gas piston/rings, magazine tube, hammer/sear, shell stop), enlarged/beveled loading port, elongated elevator, and anodized follower for smooth operation. Outside, an adjustable stock allows for 1.25 in. of LOP flexibility, the stock and streamlined forend feature Mossberg signature texturing for a secure grip, and a front fiber optic sight helps keep you on target. This Feild model features a 28" vent rib barrel and Accu-Set choke tubes.