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 fore-end 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.