Possible Clues:

• Radar was one: Abbr.
• Master Sgt., for one
• Barracks fig.
• T.Sgt., e.g.
• Barracks boss, for short
• 22-Down, e.g.: Abbr
• It's below grade one: Abbr.
• In brief, a corporal or sergeant
• U.S.A.F. E-7, e.g.
• How the North gets firm but not private