gunnery sergeant

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A noncommissioned rank in the US Marine Corps that is above staff sergeant and below master sergeant and first sergeant.
• noun One who holds this rank.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun military, US A non-commissioned officer of rank E-7 in the United States Marine Corps, ranking above a staff sergeant and below a master sergeant or first sergeant.

from WordNet 3.0 Copyright 2006 by Princeton University. All rights reserved.

• noun a noncommissioned officer ranking above a staff sergeant in the marines