I will begin by saying that I spent four and a half years as mortar infantry. I did a tour in Afghanistan with Bravo Company, 1/501st Parachute Infantry Regiment, and a tour in Iraq with Bravo Company, 4/23rd Stryker Infantry Battalion. Therefore I apologize in advance to all the gun bunnies that read this and wonder why I don’t focus as much on their discipline as I do the mortar. I would rather not guess on what intricacies are involved in your trade. This paper will be split into two parts. The first will describe how indirect fire works. The second part will give my observations on how indirect fire is used and misused in the current conflicts.
Indirect fire has been with us almost as long as the invention of gunpowder. It didn’t take long for someone to realize once something can launch a small object far, it can launch a bigger object far as well. As tactics evolved, so did the methods in which indirect fire was delivered to the battlefield. The modern day models have led to two different paths: mortars and artillery.
The major difference between the two is that mortars deliver their rounds in a high, arching fire. Artillery pieces tend to fire in a lower arc over a longer distance. You can think of it as simply a larger rifle. A second difference is that artillery pieces tend to be larger in both firepower and caliber. The largest mortar piece the US military fields is a 120mm mortar. The largest artillery piece is a 155mm cannon. The advantage of artillery is the greater distance and firepower, while mortars are able to deliver highly accurate rounds with impressive mobility, speed, and cover. A 120 mm mortar team can consist of three men, fit in the back of a standard humvee, and set up and take down in a matter of minutes.
However, effective indirect fire comes from three sources. The first is the gun crew, generally anywhere from 2 to 5 personnel. The second is the fire direction control (FDC), who is generally two soldiers. Occasionally there will be a third running the radio as a Radio Telephone Operator (RTO) if there is a surplus of personnel. This is the exception, however. The two soldiers working as FDC will function as a primary, who will be working on a mortar ballistic computer. The second soldier will be working as a check, to make sure that the data entered and received matches up with the primary’s data.
The third part of indirect fire comes from the Forward Observers (FO). FOs may refer to infantry soldiers in the field who call in fire. However, dedicated FOs are an MOS in and of themselves, assigned to the Artillery Branch. They tend to work in pairs, either moving far ahead of friendly lines or on the front line, calling in fire on targets. It takes a special kind of mentality to be an effective Forward Observer, and part of that is an extreme attention of detail. All the FOs I have worked with were meticulous about data, possessed nerves of steel under fire, and loved their work. I do not know if the work makes the man or the man is attracted to the work; I believe that the answer is somewhere in between.
Now that the major three parts of effective indirect fire have been discussed, I will lay out how a typical call for fire occurs. The FO spots a target, and decides what kind of mission he will call. A grid mission is just that. The FO estimates the map grid the target is on, and calls it in to the FDC. The second kind of mission is a polar mission. The FO gives the FDC his position, and calls the azimuth and distance the target is from him.
Once the FO has given the mission type and data to the FDC, the FDC will generally use the mortar ballistic computers to compute the data in question. Once the data is computed, and double checked, the firing data is given to the gun crew. This data comes in the form of MILS (horizontal) and ELEVATION (vertical) on the gun sight. As the gunner dials in the data, the assistant gunner will manipulate the gun to level the bubbles on the gun sight. Once the bubbles are leveled, the gun is ready to fire. After each round the bubbles are checked, and re-leveled as necessary before firing again. The FO will adjust the data from where the rounds land, or call for “fire for effect”, at which a number of rounds are fired at once.
Data must be accurate. In training, one mil off is “acceptable”. During combat, the data must be exact. Failure to do so can result in courts martial if something goes horribly wrong. Gunning is serious business, and often the gunner is a specialist, sometimes a private first class. This is a tremendous amount of responsibility for an enlisted soldier, and gunners tend to be steady, intelligent, and reliable.
Gunners may also fire independently of an FDC or FO on targets visible in the open. This is called direct lay and is complex to describe the particulars of. In a nutshell, it involves the gunner using the explosions to direct his rounds on the targets in question.
Part 2: Indirect Fire and COIN Warfare
It is my belief that indirect fire, by its very name, has acquired a bad name in command circles. Captains and Lieutenants are, in my experience, enthralled with the experience of calling in air strikes with laser guided 500 pound bombs. In the same breath, they will deride indirect fire as being too inaccurate. Often much of this extends from ignorance. Many infantry commanders spend their O-1 to O-3 careers as infantry platoon commanders before assuming command of a company. They have little experience with mortars in a tactical sense. To paraphrase Anthony Swofford, they know that mortars are a good thing to have, but what the hell are they supposed to do with them?
In Afghanistan, we were in contact for almost ten minutes while the company commander tried to get helicopter support, before he allowed the single 60mm mortar to fire. Six rounds later the enemy stopped firing. Due to there being a mine field between us and the enemy, no battle damage assessment was available, but the FO Chief on scene believed that we had killed them all. To this captain’s credit, he became a true believer shortly afterwards.
Mortars are used to great effect by the Afghanis, where the mountainous terrain tends to preclude the use of artillery. However, the high arching fires are perfect for the terrain of Afghanistan. These battles tend to be indirect “knife fights” of a kilometer or less, and can become duels between gun teams.
The Iraqis often used mortars as well, to target Forward Operating Bases and troops in the open. However, we were precluded from firing mortars into Mosul, even while under direct contact, and also into Tal Afar. Instead command believed that helicopter gun strikes (with Hellfire missiles) were more accurate. I don’t totally understand this, but believe that helicopters are more PR friendly to the high command.
Our total lack of use resulted in the trained mortar soldiers running a detainee center, then being sent to the line infantry platoons, and finally ending up being part of the company commanders Tactical Action Command with the forward observers assigned to the company.
This action is writ large in the bigger Army, with artillery units unable to qualify with their guns. In the new COIN Army, artillery units have been retrained as military police and civil affairs troops, as their accurate and dependable firepower is considered unnecessary in the hearts and minds style battle.
The blast radius of the smallest mortar, the 60mm mortar, is roughly 30 yards. The range is 2490 meters. With current technology, FO’s are able to get 10 digit grids, which are accurate of up to one meter.
I use these stats to give the audience a basis before I describe why the current roles of engagement are foolish and almost treasonous.
The total fear of using indirect fire seems to come from the high command’s nightmare of massive civilian casualties in the current Afghanistan operation. This speaks of a complete lack of trust in the enlisted soldiers and non commissioned officers responsible for indirect fire and their training. There is no excuse not to call in mortars on troops in the open, with no civilians around, even if they are firing in an urban area. However, when you’re sitting in Kabul designing a rules of engagement to be incredibly media friendly, this is the sort of thinking that works.
When you’re a grunt pinned down by automatic fire, unable to pop your head up because of the volume of firepower coming your way, and need help, it is criminal to be unable to call in quick and accurate indirect firepower.
I hope this essay helps the civilian public understand the application and use of indirect fire in our current conflicts.
