The United States Navy and United States Coast Guard occupational rating of gunner's mate (GM) is a designation given by the Bureau of Naval Personnel (BUPERS) to enlisted sailors who either satisfactorily complete initial Gunner's Mate "A" school training, or who "strike" for the rating by showing competence in the field of ordnance. When "striking" one isn't required to be a seaman, but must belong to one of three undesignated rates: Fireman (FN), Seaman (SN), or Airman (AN).
Gunner's Mate (GM) is a designation given by the Bureau of Naval Personnel (BUPERS) to enlisted sailors who either successfully complete initial Gunner's Mate "A" school training, or demonstrate competence in ordnance through "striking".