Turret

Automated turrets are automated, unmanned machine guns which are capable of sensing, and attacking targets that are hostile to the faction, or organization to which they belong.

Background
They are employed by military organizations, such as the Enclave, or the Brotherhood of Steel, and historic sites for security purposes, such as the Museum of History. Though in the latter case their former operators have been long since dead. In one case, a raider group near the Arlington Library has reprogrammed turrets to protect a camp, and a chem lab.