18.5" Cylinder-bore barrel with ATI heat shield and two, 2.75-inch sections of Picatinny rail. Magazine tube holds five 12-gauge 3" magnum or six 2.75" shells. A machined, anodized aluminum, ATI Halo Side Saddle attaches to the 500’s receiver, holding up to 9 ATI shell holders (6 left and 3 right.) The Side Saddle is also drilled and tapped for a top Picatinny rail, and one is included. The rail is grooved along its centerline to serve as the rear sight. A winged-post front sight attaches to the end of the heat shield. Stocks are ATI’s polymer Akita forend and the company’s Scorpion TacLite pistol grip stock, the latter having 3.3 inches of length-of-pull adjustment in six different positions and has adjustable comb.