M51 Skysweeper
![Skysweeper on wheeled base at the United States Army Ordnance Museum.](/Images/godic/202502/11/Skysweeper_33918.jpg")
![Skysweeper in firing position.](/Images/godic/202502/11/Skysweeper3919.jpg")
![Retired Japan Ground Self Defense Force Skysweeper JGSDF Shimoshidu base, Chiba.](/Images/godic/202502/11/M51_Antiaircraft_gun_023919.jpg")
Skysweeper (Gun, M51, Antiaircraft or Gun automatic, 75-mm T83E6, and E7, recoil mechanism, and loader rammer) was an anti-aircraft gun deployed in the early 1950s by both the U.S. Army and U.S. Air Force. It was the first such gun to combine a gun laying radar, M10 analog computer (director), and an autoloader on a single carriage.