Automated Turrets are machine guns that are able to attack enemies that are not part of the owners faction.
They have unlimited ammo and can fire either bullets or lasers. Note that when you encounter a large group of turrets there is probably a Terminal that is controlling them. Like all other robots across the Wasteland, if the player targets the robots combat inhibitor (or in this case targeting chip) it will frenzy.
Turrets have different models, starting with the Mark I Turret and going up to the Mark VIII (with Broken Steel).