Springfield Armory(R) 1911 Operator AOS is a semi-automatic pistol chambered in .45 ACP. It features a 4.25 in match-grade barrel a black carbon steel slide and frame and an AOS optics-ready slide configuration. This 8-round Operator configuration incorporates an extended beavertail accessory rail and traditional single-action 1911 operating system.Key Features 4.25 in match-grade barrel chambered in .45 ACP Single-action semi-automatic operation with 8-round detachable magazine AOS optics-ready slide configuration Carbon steel frame with extended beavertail Accessory rail for compatible lights and accessories Commander-length 1911 Operator configurationSpringfield Armory(R) offers firearms designed for defensive duty sporting and recreational applications. The company combines established firearm designs with modern manufacturing materials and feature sets. Springfield Armory(R) firearms include a broad selection of pistols and long guns designed around reliability practical handling and contemporary shooting requirements.