 A Battalion in the Marine Corps is headed by the Battalion Commander , usually a Lieutenant Colonel and sometimes a Colonel , his staff , headquarters , and the Battalion Sergeant Major . It usually consists of 3 @-@ 5 companies , with a total of 300 to 1 @,@ 200 Marines . 2nd Battalion 9th Marines comprises a Headquarters & Service ( H & S ) Company , Weapons Company and three Infantry Companies : Echo , Fox , and Golf . During the Vietnam war the Battalion comprised Headquarters & Service ( H & S ) Company , and Four Infantry Companies Echo , Fox , Golf , and Hotel . Each Company had its own weapons platoon with 3 squads of M 60 machine guns ( 7 @.@ 62 ) and 60 mm mortars and <unk> 3 @.@ 5 inch Rocket <unk> ( super <unk> ) or later <unk> . 
