You have asked for information on the GUNNERS MATE rating. The rating symbol is a Pair of Crossed Cannon
The U.S. Navy is made up of four distinct groups of technical rating specialist. These categories are:
Administrative and Medical
Aviation
Hull
Construction
The term SEABEE was originally coined to define the Naval combat construction forces assigned to the Naval Civil Engineering Corps, and the SEABEES became a recognized organization in 1942. The traditional SEABEE specialty ratings are made up of seven classifications shown as the top left seven on the home page. As SEABEES tend to be self sufficient in a combat zone or other deployed area, other ratings are assigned to the SEABEES to provide the skills necessary to accomplish this.
While any rating within the U.S. Navy can be billeted with a SEABEE group depending upon the nature of the task at hand, the home page includes thirteen typical other ratings that were most assigned to be part of a SEABEE unit during the Vietnam Era.
Gunner's Mate (GM):
Navy GMs operate, maintain and repair all gunnery equipment, rocket launchers, guns, gun mounts, turrets, projectors and associated equipment. They make detailed casualty analyses and repairs of electrical, electronic, hydraulic and mechanical systems. They also test and inspect ammunition, missiles and their ordnance components. GMs train and supervise personnel in the handling and stowage of ammunition, missiles and assigned ordnance equipment.