The Marine Corps MOS 6300 is for Basic Avionics Marines. These Marines are responsible for the maintenance, repair, installation, and testing of electronic countermeasure systems aboard the EA-6B aircraft. They also provide direct and indirect support of all aviation weapon systems.
Marines with MOS 6300 progress through specific hard skill MOSs and ultimately are assigned MOS 6391, Avionics Maintenance Chief. They are required to have confidential or secret security clearance from the Department of Defense.