Master Gunnery Sergeant (MGySgt) is the ninth and highest enlisted rank (along with the grade-equivalent ranks of Sergeant Major and Sergeant Major of the Marine Corps) in the United States Marine Corps. Master Gunnery Sergeants are senior staff non-commissioned officers (SNCOs), and are assigned a pay grade of E-9.Master Gunnery Sergeants are sometimes referred to by the nicknames "Master Guns" or "Master Gunny".