 The most easily distinguished difference between generations is the extractor.The first generation has a traditional external extractor parallel to the side of the gun, while the second generation has a button-head hex screw to the rear of the extractor, which is at an angle to the side of the gun.In a 2004 "Guns & Ammo" review, Wiley Clapp said, "Ingenuity is often nothing more than a combination of existing principles applied in unique ways.