Some details about the action ,
"A bolt carrier measuring approximately 1.125" square by 4.5" inches in length rides below a guide rod and a “bolt top” keyed to the bolt. While fundamentally a blowback, the gun’s design also relies on a separate so-called dead-blow weight, mimicking the function of a like-named hammer. The weight measures 0.750" square by 1.875" in length and is metal-injection-molded from tungsten—an elemental metal with a density 1.7 times that of lead. According to Ruger engineers, the weight accounts for nearly half of the bolt assembly’s mass, which keeps its overall size reasonable yet still allows the mechanism to counteract the recoil of even 9 mm Luger +P cartridges. The weight rests in a pocket machined into the bolt carrier that allows about 0.025" of play fore and aft, and, in operation, comes to rest a split second after the carrier, retarding the carrier’s velocity somewhat as it changes direction. That helps prevent the “bolt bounce” effect often associated with such guns, which can result in receiver battering and a lack of reliability. It also softens the blow of the carrier against the receiver somewhat, even though that task is primarily handled by a elastomer buffer attached to the rear of the recoil spring assembly."
