M202 XP machine gun
From Halopedia, the Halo wiki
The M202 XP Machine Gun is a type of stationary gun turret used by the UNSC in the early 2500's. They were obsolete as of 2541, used for little more than training. They were replaced by the more advanced M247 GP Machine Gun model.
These Machine Guns can be hooked up to automated fire controls, but they are easy to avoid because they have large minimum angle of fire.
