Complex sentence: In the United States Marine Corps, First Sergeant (abbreviated 1stSgt) is one level below Sergeant Major and Master Gunnery Sergeant and is the next rank above Gunnery Sergeant; it is equal in grade to Master Sergeant, although the two ranks have different responsibilities.
Split into simpler sentences: In the United States Marine Corps, First Sergeant (abbreviated 1stSgt) is one level below Sergeant Major and Master Gunnery Sergeant and is the next rank above Gunnery Sergeant. It is equal in grade to Master Sergeant, although the two ranks have different responsibilities.