Automatic Computing Sights, Types K-3, K-4, K-5 Handbook
This is an original WWII-era Preliminary Handbook of Service and Maintenance Instructions for the Sperry K-series turret-mounted Gun Sight, K-3, K-4, and K-5, dated Jan 1942. The K-series sights were found in US Army Air Force bombers such as the B-17 Flying Fortress and B-24 Liberator, and used to fire 50-caliber machine guns.
This 30-page handbook includes text, tables, illustrations, and fold-out diagrams. It is in reasonable condition given its age. The cover page is from the US Army Air Service Command, but the following attached pages are direct Sperry documents.