Marine Corps Reference Publication MCRP 3-10F.2 (Formerly MCWP 3-16.6) Supporting Arms Observer, Spotter, and Controller 2 May 2016, provides the techniques and procedures for requesting and adjusting supporting arms. This publication provides techniques and procedures for requesting, adjusting, and controlling mortars, artillery, naval gunfire, and close air support. It is intended as a field reference for supporting arms observers (mortar and artillery forward observers, naval gunfire spotters, and forward air controllers) and as a study guide and field reference for personnel seeking information on supporting arms procedures. Fleet Marine Force Manual (FMFM) 6-8, Supporting Arms Observer, Spotter, and Controller, dated 24 June 1994.