The semi-automatic receivers are sculpted from high strength aluminum by state-of-the-art CNC machines for exact dimension & tolerance. These receivers have a blue anodized finish with tasteful laser etching. The SKB HS300 Field Camo 12 Gauge shotgun has a maximum capacity of 4 - 3" shot shells; three in the magazine tube with one in the chamber. Each shotgun is provided with a set of six different stock shims to assist the shooter in obtaining a personalized fit to the sighting plane. The removable stock shim will adjust for either the stock's cast or drop dimension. The new HS300 is a hybrid operating system which includes an inertia bolt and a self-regulating gas valve. This combination utilizes an optimum amount of combustion gases and the kinetic energy of the recoiling bolt to cycle the operating system while reducing felt recoil.