ATK said the award is part of a multi-year contract originally signed in July 2007.
ATK's worldwide sales of PGU-15A/B ammunition now total than $29 million.
Dan Olson, ATK’s vice president and general manager for integrated weapon systems, said the Air Force uses the cartridges for A-10 training exercises.
ATK will begin delivering the ammunition this year.
ATK's integrated weapon systems division will produce the rounds in Radford, Va. and Rocket Center, W.Va.