Soldier Combat Skills

Chapter 15-1 – Unexploded Ordnance

Being able to recognize a UXO is the first and most important step in reacting to a UXO hazard. There is a multitude of ordnance used throughout the world, and it comes in all shapes and sizes. This chapter explains and shows some of the general identifying features of the different types of ordnance, both foreign and US. To learn more about UXOs, see FM 4-30.51. In this chapter, ordnance is divided into four main types: dropped, projected, thrown, and placed.


15-1. Regardless of its type or purpose, dropped ordnance is dispensed or dropped from an aircraft. Dropped ordnance is divided into three subgroups: bombs; dispensers, which contain submunitions; and submunitions.


15-2. Bombs can be general purpose or chemical-agent filled.

General Purpose Bombs

15-3. General purpose bombs come in many shapes and sizes depending on the country that made them and how they are to be used. Most of these bombs are built the same and consist of a metal container, a fuse, and stabilizing device. The metal container (called the bomb body) holds an explosive or chemical filler. The body may be in one or multiple pieces.

Chemical-Agent Filled Bombs

15-4. Chemical-agent filled bombs are built the same as general purpose bombs. They have a chemical filler in place of an explosive filler. Color codes and markings may be used to identify chemical bombs. For example, the US and NATO color code for chemical munitions is a gray background with a dark green band. The former Soviet Union uses a combination of green, red, and blue markings to the nose and tail sections to indicate chemical agents. Soviet bombs all have a gray background.


15-5. Fuses used to initiate bombs are either mechanical or electrical, and are generally placed in the bomb’s nose or tail section, internally or externally. They may be hidden, as when covered by a fin assembly. As shipped, fuses are in a safe (unarmed) condition and function only once armed.

Mechanical–Mechanical fusing, whether in the nose or in the tail, is generally armed by some type of arming vane. The arming vane assembly operates like a propeller to line up all of the fuse parts so the fuse will become armed.

Electrical–Electrical fuses have an electric charging assembly in place of an arming vane. They are armed by using power from the aircraft. Just before the pilot releases the bomb, the aircraft supplies the required electrical charge to the bomb’s fuse. Action of the fuse may be impact, proximity, or delay. Impact fuses function when they hit the target. Proximity fuses function when bombs reach a predetermined height above the target.

Delay–Delay fuses contain an element that delays explosion for a fixed time after impact. To be safe, personnel should consider that all bombs have the most dangerous kind of fusing, proximity or delay. Approaching a proximity or delay-fused bomb causes unnecessary risk to personnel and equipment. Although it should function before it hits the target, proximity fusing may not always do so. Once the bomb hits the ground, the proximity fuse can still function. It can sense a change in the area around the bomb and detonate. Delay fusing can be mechanical, electrical, or chemical. Mechanical and electrical-delay fuses are nothing more than clockwork mechanisms. The chemical-delay fuse uses a chemical compound inside the fuse to cause a chemical reaction with the firing system. Delay fusing times can range from minutes to days.


15-6. Dispensers may be classified as another type of dropped ordnance. Like bombs, they are carried by aircraft. Their payload, however, is smaller ordnance called submunitions. Dispensers come in a variety of shapes and sizes depending on the payload inside. Some dispensers are reusable, and some are one-time-use items.


15-7. Submunitions are classified as bomblets, grenades, or mines. They are small explosive-filled or chemical-filled items designed for saturation coverage of a large area. Each of these delivery systems disperses its payload of submunitions while still in flight, and the submunitions drop over the target. On the battlefield, submunitions are widely used in both offensive and defensive missions. Submunitions are used to destroy an enemy in place (impact) or to slow or prevent enemy movement away from or through an area (area denial). Impact submunitions go off when they hit the ground.


15-8. Area-denial submunitions, including FASCAM, have a limited active life and self-destruct after their active life has expired. The ball-type submunitions shown in Figure 15-1 are antipersonnel. They are very small and are delivered on known concentrations of enemy personnel.

Note: Never approach a dispenser or any part of a dispenser you find on the battlefield. The payload of submunitions always scatters in the area where the dispenser hit the ground.

Area-Denial Submunitions–The submunition shown in Figure 15-2 is scattered across an area and, like a land mine, it will not blow up until pressure is put on it. They are area-denial, antipersonnel submunitions (FASCAM). These submunitions are delivered into areas for use as mines. When they hit the ground, trip wires kick out up to 20 feet from the mine. All area-denial submunitions use anti-disturbance fusing with self-destruct fusing as a backup. The self-destruct time can vary from a couple of hours to as long as several days.

Antipersonnel and Anti-Materiel (AMAT) Submunitions–The DP submunition shown in Figure 15-3 has a shaped charge for penetrating hard targets but is also used against personnel. These submunitions are delivered by artillery or rockets. The arming ribbon serves two purposes, as it arms the fuse as the submunition comes down and also stabilizes the submunition so that it hits the target straight on.

AMAT and Antitank Submunitions–The AMAT or antitank submunitions shown in Figure 15-4 are designed to destroy hard targets such as vehicles and equipment. They are dispersed from an aircraft-dropped dispenser and function when they hit a target or the ground. Drogue parachutes stabilize these submunitions in flight so they hit their targets straight on. Others have a fin assembly that stabilizes the submunition instead of the drogue parachute.

Antitank Area-Denial Submunitions–Antitank area-denial submunitions can be delivered by aircraft, artillery, and even some engineer vehicles. These FASCAMs have magnetic fusing and function when they receive a signal from metallic objects. These submunitions, similar to the antipersonnel area-denial submunitions, also have anti-disturbance and self-destruct fusing. Antitank and antipersonnel area-denial mines are usually found deployed together.


15-9. All projected ordnance is fired from some type of launcher or gun tube. Projected ordnance falls into the following five subgroups:

  • Projectiles.
  • Mortars.
  • Rockets.
  • Guided missiles.
  • Rifle grenades.


15-10. Projectiles range from 20 millimeters to 16 inches in diameter and from 2 inches to 4 feet in length. They can be filled with explosives, chemicals (to include riot-control agents such as CS), white phosphorus (WP), illumination flares, or submunitions. Projectile bodies can be one piece of metal or multiple sections fastened together.

15-11. Projectiles, like bombs, can have impact or proximity fusing. They can also be fused with time-delay fusing that functions at a preset time after firing. For safety reasons, all projectiles should be considered as having proximity fusing. Getting too close to proximity fusing will cause the fuse to function, and the projectile will blow up. Depending on the type of filler and design of the projectile, the fuse can be in the nose or base.

15-12. There are two ways projectiles are stabilized- by spin or fin. Spin-stabilized projectiles use rotating bands near the rear section to stabilize the projectile. Riding along the internal lands and grooves of the gun tube, these bands create a stabilizing spin as the projectile is fired. Fin-stabilized projectiles may have either fixed fins or folding fins. Folding fins unfold after the projectile leaves the gun tube to stabilize the projectile.


15-13. Mortars range from 45 millimeters to 280 millimeters in diameter. Like projectiles, mortar shells can be filled with explosives, toxic chemicals, WP, or illumination flares. Mortars generally have thinner metal bodies than projectiles but use the same kind of fusing. Like projectiles, mortars are stabilized in flight by fin or spin. Most mortars are fin stabilized.


15-14. A rocket may be defined as a self-propelled projectile. Unlike guided missiles, rockets cannot be controlled in flight. Rockets range in diameter from 37 millimeters to over 380 millimeters. They can range in length from 1 foot to over 9 feet. There is no standard shape or size for rockets. All rockets consist of a warhead section, motor section, and fuse. They are stabilized in flight by fins, or canted nozzles, that are attached to the motor.

15-15. The warhead is the portion of the rocket that produces the desired effect. It can be filled with explosives, toxic chemicals, WP, submunitions, CS, or illumination flares. The motor propels the rocket to the target. The fuse is the component that initiates the desired effect at the desired time. Rockets use the same type of fusing as projectiles and mortars. The fuse may be located in the nose or internally between the warhead and the motor.

15-16. Generally, the rocket motor will not create an additional hazard, because the motor is usually burned out shortly after the rocket leaves the launcher.


15-17. Guided missiles are like rockets, as they consist of the same parts; however, missiles are guided to their target by various guidance systems. Some of the smaller missiles, such as the tube-launched, optically tracked, wire-guided (TOW) and Dragon missiles, are wire-guided by the gunner to their targets.

15-18. Larger missiles, such as the phased-array, tracking radar intercept on target (PATRIOT) and the Sparrow are guided by radar to their target. Guided missiles use internal, proximity fusing and therefore, do not approach any guided missile you find laying on the battlefield.


15-19. Rifle grenades look like mortars and are fired from a rifle that is equipped with a grenade launcher or an adapter. Many countries use rifle grenades as an Infantry direct-fire weapon. Some rifle grenades are propelled by specially designed blank cartridges, while others are propelled by standard ball cartridges. Rifle grenades may be filled with HEs, WP, CS, illumination flares, or colored screening smoke. They range in size from the small antipersonnel rifle grenade to the larger antitank rifle grenade. Antipersonnel rifle grenades use impact fusing. Some rifle grenades, such as the antitank version, have internal fusing behind the warhead; this type of fusing still functions on impact with the target.


15-20. Hand grenades are small items that may be held in one hand and thrown. All grenades have three main parts: a body, a fuse with a pull ring and safety clip assembly, and a filler. Never pick up a grenade you find on the battlefield, even if the spoon and safety pin are still attached. All grenades found laying on a battlefield should be considered booby-trapped. Thrown ordnance, commonly known as hand grenades, can be classified by use as follows:

  • Fragmentation (also called defensive)
  • Offensive
  • Antitank
  • Smoke
  • Illumination


15-21. Fragmentation grenades are the most common type of grenade and may be used as offensive or defensive weapons (see Figure 15-5). They have metal or plastic bodies that hold explosive fillers. These grenades produce casualties by high-velocity projection of fragments when they blow up. The fragmentation comes from the metal body or a metal fragmentation sleeve that can be internal or attached to the outside of the grenade. These grenades use a burning delay fuse that functions 3 to 5 seconds after the safety lever is released.


15-22. Offensive grenades have a plastic or cardboard body and are not designed to have a lot of fragmentation. Their damage is caused from the over pressure of the explosive blast. These grenades use a burning-delay fuse that functions 3 to 5 seconds after the safety lever is released.


15-23. Antitank grenades are designed to be thrown at tanks and other armored vehicles. They have a shaped-charge explosive warhead and are stabilized in flight by a spring-deployed parachute or a cloth streamer (Figure 15-6). These grenades use impact fuses.


15-24. The two types of smoke grenades are bursting and burning (Figure 15-7). They may be made of rubber, metal, or plastic. Bursting-type smoke grenades are filled with WP and blow up when the fuse functions. These grenades use a burning delay fuse that functions 3 to 5 seconds after the safety lever is released. Burning-type smoke grenades produce colored smoke and use an instant-action fuse. There is no delay once the spoon is released. This is the same type of grenade that is used to dispense riot-control agents such as CS.


15-25. Illumination grenades are used for illuminating, signaling, and as an incendiary agent (Figure 15-8). The metal body breaks apart after the fuse functions and dispenses an illumination flare. This type of grenade uses a burning-delay fuse that functions 3 to 5 seconds after the safety lever is released.

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