Fire discipline Fire discipline is a system of communication in the military , primarily the artillery . By definition , fire discipline is the language of fire control . It consists of words , phrases , rules , and conventions which have specific meanings and which result in some definite action at the guns . All ranks concerned in fire control must therefore be thoroughly familiar with the language and the resulting actions . The aim of fire discipline is to ensure that in response to fire orders ( from a forward observer ) , appropriate action is taken at the guns , strictly in accordance with the intentions of the originator , and with a minimal amount of delay . Six elements of a call for fire . An initial call for fire ( from an artillery battery ) Call for fire . In the United States military , artillery is usually brought into play when a forward observer sends a three part " call for f " missions " available , the most common in a wartime scenario is the basic " adjust fire " : Fire missions are started with a warning stating the observer identification ( call sign ) and the type of mission to be fired : " M10 , this is G35 , Adjust fire , over . " The next radio transmission will be from the artillery battery , mirroring what was sent : " G35 this is M10 , adjust fire , out " . The forward observer then sends a six - digit military grid reference system ( MGRS ) grid coordinate with a 100 , 000 - meter grid square identifier : " Grid ES 923 945 , over " . The forward observer will always get a reply mirroring what he had originally sent : " Grid ES 923 945 , out " The last element is the description of the target , and optionally , method of engagement and method of fire and control : " Two BMPs and 20 enemy dismounted infantry in the open , over . " The phrase " in the open " is the degree of protection of the target . If the forward observer does not specify the method of engagement and the method of fire and control , the Fire Direction Center will choose the ammunition type and fusing , be it for a target in foxholes or dug in , in dense foliage or in a bunker . If the forward observer or any friendly troops are within 600 meters of the impact point , to keep themselves safe , the forward observer would declare " danger close " in this last element . " Two BMPs and 20 enemy dismounts in the open , out . " The next step would be for the Fire Direction Centre ( FDC ) to send an MTO , or a message to the observer , describing what ammunition will be used , what gun is shooting the spotting rounds , and what guns will fire the actual mission . The identifiers are the last letter of the call sign for the gun and battery in question ( one gun adjusts , the next call sign fires the actual fire for effect and how many shells each gun fires in the mission . For example , if there are three guns in the battery , the FDC decides that each fires five rounds , that means fifteen rounds will be fired : " R , F , DPICM in effect , 5 rounds , over . " The forward observer would reply : " R , F , DPICM in effect , 5 rounds out . " The FDC will then send the mission out to the individual guns to fire . After the guns get oriented and loaded , the mission is fired . The FDC will then send " Shot , over " , to which the forward observer replies " Shot , out " . This designates that the guns have fired . Corrections to his or her transmission are possible at any time up to this point . After shot is called , the rounds are on the way and any corrections or retractions are impossible . The FDC will then send a warning that the rounds are five seconds from impact , so that the FO may observe the impact of the rounds for adjustment : " Splash , over " the reply is " Splash , out " . Sometimes , the initial target location might be off . This is why the mission is called " Adjust fire " : the FO has the chance to adjust where the final impact will be when the full battery fires on the target . The first step for adjustment is to send the FO ' s direction to the target in mil s and the correction in meters : " Direction 2500 , add 100 , left 150 , over " Direction is rounded to the nearest 10 mils . to increase the range , the FO sends ADD , to decrease the FO uses DROP . " Direction 2500 , add 100 , left 150 , out . " Assuming the FO ' s spotting round lands within the effective radius of the munitions , the FO would then send the command : " Fire for effect , over " . The proper reply to this would be : " Fire for effect , out . " After this , the FO would then receive another MTO , another " Shot " and " Splash " notification . Again , however , things might not go as planned ; the rounds fired might not be sufficient to destroy the target . The FO would then send the proword " Repeat , over . " The proword " repeat " is never used anywhere on a radio but when communicating that a forward observer wants the previous artillery battery to fire the mission again . " Repeat , out . " Assuming allied forces have destroyed the target , the FO would then send an end of mission report such as : " M10 , this is G35 , End of mission : 2 BMPs destroyed , estimate 25 casualties , over . " The battery would then reply : " G35 this is M10 , End of mission , 2 BMPs destroyed , estimate 25 casualties , out . " There are many different missions . The last - ditch mission is " immediate suppression " : Every gun in any concerned battery immediately fires whatever round and fuse is loaded , possibly from someone else ' s , or more than one callsign ' s mission . The FO may end up getting parachute flares , white phosphorus illumination , DPICM , and VT - HE rounds on the target in the same shot .