The Hatfield SAS USA20W is a semi-automatic shotgun featuring a turkish walnut buttstock and forend with deluxe checkering and a recoil absorbing 0.5" ventilated rubber recoil pad. The SAS operating system is a unique blend of gas and inertia, where a gas piston moves only one inch to kick the bolt rearward and start the bolts inertia travel through the operating cycle; fewer moving parts provides higher dependability. The SAS gas/inertia system operates dependably with most commercially available 2.75" and 3" shells.