The Gunner's Mate "A" school is held at Naval Training Center Great Lakes, Illinois. While the school was originally very hands-on, it is now primarily conducted through self-study computer based training (CBT). The training focuses on the operation, maintenance, and troubleshooting of Naval guns and missile launchers as well as a strong emphasis on basic explosives, guidance and tracking systems, small arms, Naval ammunition classification, and safety. Upon completion of this basic training, enlisted members often continue on to a specialized "C" school, where they learn a particular weapons system.
The Gunner's Mate rating is primarily surface based. Closely associated Naval occupational ratings are Fire Controlman (FC), Torpedoman (TM), Aviation Ordanance Specialist (AO), Weapon's Technician (WT), and Mineman (MN).
The Gunner's Mate rating is one of the three original ratings created when the Navy introduced the rating system in 1797. The others include Boatswain's Mate (BM) and Master at Arms (MA). The rating is also among the top five source ratings for enlisted Naval Special Warfare candidates.