Marine Corps Jobs: Fire Support MOS 0861

With the word "fire" in the job title, one might think a Fire Support Marine was similar to a civilian firefighter. But the title refers to a different type of fire: These Marines perform duties related to the observation, conduct, and control of artillery and naval gunfire.

The Marine Corps' Military Occupational Specialty (MOS) code system distinguishes job positions, roles, and duties within the Marine Corps. This role is designated as MOS 0861.

MOS 0861 was previously titled "Fire Support Man," but was changed along with several other Marine job titles in 2016 to be gender neutral.

This is a primary MOS (PMOS) and the rank range extends from Master Gunnery Sergeant to Private. Primary MOS identify a service member's primary skills and/or training.

Job Duties of MOS 0861

These Marines observe and adjust artillery and naval surface fire support, which includes using laser designators and rangefinders, employing radar beacons for support ships and coordinating lethal and non-lethal fire support assets such as mortars, rockets, and cannons.

These Marines also operate sophisticated communications equipment, as they're tasked with establishing radio networks for voice and other communications, including during combat operations. And they also operate Marine Corps fire support systems.

The training for this position is rigorous and demanding; roughly 25 percent of those who enter the training program fails to advance and are recycled into other Marine jobs.

Requirements for Fire Control Marines

Marines do not step into this position without first meeting several prerequisites and undergoing specific training.

First, a Marine needs a score of 100 or higher on the general technical (GT) segment of the Armed Service Vocational Aptitude Battery (ASVAB) tests. He or she must have normal color vision (meaning no colorblindness) and overall vision that's correctable to 20/20.

Another requirement of this job, since these Marines deal with sensitive weaponry and combat plans, is a secret security clearance from the Department of Defense. This involves a background check of a person's character and finances, and a history of alcohol abuse or illegal drug use may be disqualifying factors.

Marines in this job must be U.S. citizens.

Training for Fire Control Marines

All applicants for this MOS must complete the six-week Marine Artillery Scout Observer Course (MASOC) at Fort Sill in Oklahoma, as well as the Fire Support Marine Course at Coronado, California. As mentioned previously, MASOC is known to hold Marines to extremely high standards.

The course includes written tests weekly and three graded live fire missions. If you flunk any of the tests or live fire missions, you're out of the program.

Because this is a PMOS, it is limited to only enlisted Marines, chief warrant officers, limited duty officers and warrant officers. These Marines are promoted to this position. 

Once they've passed their training, Marines in MOS 0861 are considered experts in all things fire support, and provide guidance in the field for infantry units. The pace can vary, but these Marines are usually on the front lines in combat situations, and their expertise is highly valued by unit commanders.