Firefighters need to know about military ordnance, since they often encounter it at the scene of fires as well as at fire stations.
Discussing all varieties of current military ordnance in one article would be impossible. They number in the hundreds. To complicate matters, older ordnance remains from as far back as the Civil War. Some housing subdivisions in the United States have been built over old military bombing ranges. In addition, civilians bring ordnance to fire stations. For example, two hand grenades were deposited at fire stations in San Antonio. Some military personnel also bring home ordnance as souvenirs. They consider such devices harmless because they have failed to detonate. However, military ordnance can still be explosive.
Photo by Mike Pickett 1. Types of grenades, probably the most common military ordnance.
This article provides an overview of military ordnance. It is not intended to be comprehensive or technical. In addition, readers should be aware that the ordnance colors and markings described here are among those frequently used but variations are common. Information is based on the author's training and experience in military and civilian bomb disposal and firefighting as well as on military technical training materials. Some devices described in this article are no longer manufactured but firefighters still encounter them.
Grenades
Probably the most common military ordnance are hand grenades. Such devices have a long handle, or spoon, placed on top. The handle extends from the top down the side of the grenade, approximately three-fourths the length of its body. A cotter or safety pin with an O-ring is inserted into the side of the fuse on top of the grenade. The spoon holds down the fuse and is locked by a safety pin. Pulling the O-ring releases the spring-held fuse and spoon, arming the grenade and causing it to detonate within seconds.
The old U.S. Army fragmentation-type grenade is olive drab in color and shaped like a small pineapple, being 23/8 inches in diameter and 43/4 long and weighing 21 ounces. A square fuse is on top. Newer grenades are also olive drab in color and are the size and shape of baseballs. Other grenades contain smoke, white phosphorus, tear gas or riot gas. These can be shaped like baseballs or soda cans and can come in a variety of colors, including gray and red. Nearly all grenades have identical-looking fuses (see photo 1). Rifle grenades can look like small bazookas or rocket shells. Grenades of 40 millimeters look like large, fat bullets.
Ammunition
Ammunition, or ammo, ranges from bullets for small arms of 7.62 mm up to 16-inch shells. These have the typical bullet shape with a brass-colored casing and a projectile, or warhead, on top. Some larger projectiles require the propellant to be separate from the warhead. Ammunition 20 mm and larger in size can contain a fuse and high explosives (HE) and are considered miniature bombs. Their projectiles are activated by the spinning of the shell or by the set-back inertia, or G force, involved in firing.
Photo by Mike Pickett 2. A gas bomb, a 500-pound general-purpose (GP) bomb and 250-pound GP bomb.
All shells have a rotating brass band on the end of the projectile that is scored, or rifled, when fired. Rifling marks on a projectile indicate it is probably armed. A lack of marks on rotating bands indicates the device has not been fired and the fuse is probably not armed, if it is a U.S.-made round of ammunition. This may not be the case with foreign-made rounds. All of these materials should be left undisturbed.
Mortar shells look much like projectile shells, except that they have no brass casing or rotating band. Propellants are clipped or attached to the back of the shells. Some of the shells have fins for stabilizing. There is little indication that a mortar round has been fired or that the warhead is armed. Mortars range in size from 60 mm up to 4.2 inches in diameter and up to 26 inches in length. They weigh up to 27 pounds.
Rockets And Missiles
Rockets and missiles are devices containing combustible materials that are sent through the air to such targets as aircraft, personnel or tanks. One difference is rockets have no guidance system whereas missiles do. The guidance on missiles can be of various types: laser, radar or wire fed out of the back.
Shoulder-fired rockets and missiles have warheads much like shells or mortars, as well as tube-like tails and fins. The tubes contain the propellant to launch the warheads. Some of the newer rockets and missiles may be enclosed inside a firing tube. They range from 2 1/2 to 3 1/2 inches in diameter and from 20 to 24 inches in length.
- Rockets. A common rocket is the 2 3/4-inch fired by aircraft or helicopters. The warheads are mated only before loading and firing. In storage and shipping, they are kept separate.
- Missiles. Missiles come in a variety of sizes, shapes and purposes. Air-to-air missiles (AIMs) are designed to shoot down other aircraft. An example is the AIM 9 Sidewinder, which homes in on the heat of jet aircraft exhaust. Air-to-ground missiles (AGMs) are fired by aircraft on such surface targets as tanks or buildings. Surface-to-Air missiles (SAMs) are devices intended to destroy aircraft or missiles in flight. An example is the Patriot missile used in the Desert Storm campaign in the Middle East in the early 1990s to destroy the Scud missiles of the Iraqis.
Mines
Photo by Mike Pickett 3. The BLU-3 is a recent version of the bomb live unit, designed to be dropped from aircraft, helicopters or projectiles.
Mines are encased explosives designed to destroy personnel, ships or vehicles. Of all ordnance worldwide, mines are the leading cause of injury and death to civilians, even long after conflicts have ended. Anti-tank mines and anti-personnel mines come in all sizes, shapes, and colors. They can look like traditional explosive devices or be designed to resemble rocks, shrubs or other parts of the environment.
Mines can be buried, hidden in buildings or dropped from the air. They have harmed their intended targets as well as innocent military and civilian victims. Mines are designed to be detonated by trip wires, pressure contact, metal passing over them, ground vibrations, sound and other special means. This is why they are among the most dangerous ordnance to handle. One of the most frequently used American military mines in Vietnam was the Claymore. It is olive drab in color and has a curved rectangular shape with folding legs on the bottom. It is detonated by a blasting cap inserted into the detonator well on top (see photo 2).
Sub-munitions
Sub-munitions are small bomblets, called bomb live units (BLUs), air-dropped from aircraft, helicopters or projectiles. The various types number about a hundred. Many are still classified by the military. When BLUs are dropped from the air, they are dropped from cluster bomb units (CBUs).
One of the first BLUs was the M83, called the butterfly bomb. Its vanes, which unfold in flight to slow its fall and to arm the bomblet, resemble a butterfly. A newer version is the BLU-3, which is about three inches in diameter and five inches long (see photo 3). It has a yellow body and metallic-colored fins that fold around the body until it is dropped. The fins of the BLU-3 bomb fold out and up when it is dropped in order to rotate the bomblet, stabilizing and arming it.
The BLU-7 is used as an anti-tank weapon. When it lands, it can blow a hole through armor plate. It is 23/4 inches in diameter, nine inches long when closed and 28 inches long when opened. In its open position, the BLU-7 bomb has a ribbon parachute to stabilize it, slow its fall and arm it.
Cartridge-Activated Devices
Photo by Mike Pickett 4. TNT (trinitrotoluene) is the explosive by which all other explosives are often measured.
There are many small explosive devices on aircraft. Because they are small, airplane maintenance crews sometimes treat them as harmless. For example, they may place such devices in their pockets, taking them home to leave them on their dressers.
Impulse cartridges look like shotgun shells, except they are usually metallic in color. They vary in size and are used for the ejection of pylons (devices that attach equipment to aircraft), launchers, racks, fuel tanks, missiles, and conventional and special stores from the wings and fuselage of aircraft. Other cartridges are used for starting jet aircraft engines. Some act as guillotines for cutting hoses or electrical lines. For example, many ejection seats in aircraft have projectile or rocket motors. A small triangle alongside the fuselage of an airplane, just below the canopy, indicates the presence of such devices.
Air-Dropped Or Gravity Bombs
Encounters with air-dropped weapons are rare, except in shipping accidents or in aircraft crashes. General-purpose (GP) bombs, nicknamed iron bombs, commonly come in weights of 250, 500, 750 and 2,000 pounds (see photo 4). The older high-drag bombs are shaped like a fat bullet with square box-shaped fins on the ends. Newer low-drag bombs are more streamlined with conical-shaped fins. They have a thick iron casing and are olive drab in color. They all have from one to three yellow bands on the nose, indicating a high-explosive filler. A gray body and red or green stripes indicate a chemical bombs. These can be lethal while in storage or shipment if the filler is leaking (also see photo 4).
The body of an air-dropped bomb has an opening in the nose and tail for the fuse and booster. The fuse slips inside a booster cup and is inserted into the bomb. The fuse contains small but powerful explosives on the end. The front has vanes, or propellers, that turn in the airstream, causing the bomb to be activated.
Most U.S.-made fuses have a small window. Green in the window indicates the fuse is unarmed, while red indicates it is armed. There are other fuses like the chemical delay, proximity (VT) and All Way. These are different in shape and may have indicators to reveal whether they are armed.
Fragmentation bombs (frags) weigh about 20 pounds and have bodies that are spiral wound with thick steel wire. They use only nose fuses.
Bulk Explosives
- TNT. Trinitrotoluene (TNT) is the explosive by which all others are often measured. It is light yellow and the one-fourth-pound size comes in a round cardboard cartridge 1 1/2 inches in diameter and 3 1/2 inches long. The one-half-pound size utilizes a rectangular cartridge measuring 3 3/4 by 1 3/4 by 1 3/4 inches The pound size is seven by 1 3/4 by 1 3/4 inches All TNT cartridges are olive drab with a blasting cap well in the end (see photo 5).
- C-3 and C-4. The C-3 explosive is the original plastic explosive that can be molded like putty. It comes in clear plastic cartridges measuring 12 by two by two inches, similar to TNT, and is off-white. The C-4 explosive is a newer version that is light yellow with 11-by-two-by-two-inch cartridges.
Pyrotechnics
Photo by Mike Pickett 5. Simulators are large firecrackers that simulate battle noises and effects.
Pyrotechnics burn rather than explode. These are U.S. Department of Transportation Class B explosives. Incendiary bombs were developed in World War II. Dropped from airplanes in clusters of 30 to 130, they broke apart in the air, starting scattered fires over large areas. Because they contain magnesium and sometimes a bursting charge, it is useless and dangerous to try to extinguish them. They are about 22 inches long with a three-inch hexagonal diameter.
Another bomb developed in World War II was napalm. A soap compound is mixed with gasoline to make a sticky solution, then poured into external fuel tanks with white phosphorous ignitors and dropped from aircraft.
Flares burn for six to 60 seconds. All but the air-dropped flares are aluminum tubes, 10 to 12 inches long and two inches in diameter and weighing from one to 11/2 pounds. Some contain expelling charges with parachutes.
Simulators
Simulators are large firecrackers that simulate battle noises and effects. The M116A1 hand grenade simulator is a white cylindrical paper tube 4.3 inches long and 2.18 inches in diameter, with a five- to 10-second fuse and an ignitor on the side. Red tape holds the ignitor to the body. The M115A2, a projectile simulator, is 7.13 inches long and 2.4 inches in diameter. The M21 artillery flash simulator consists of an outer plastic case 5.9 inches in length and two inches in diameter. The case covers two sections taped together. The upper section is a protective cap removed prior to loading. The lower section is loaded into the firing drums of the simulator and contains the pyrotechnic charge and ignitor. It is yellow or olive with white markings.
Call In The Experts
Military ordnance should always be left alone by untrained personnel. Those who find them can note their colors and markings but only if they can do so without disturbing them. When people do find them, they should contact their local civilian bomb disposal team or military bomb disposal authorities.
The author is grateful to arson investigator Larry Foraker of the San Antonio Fire Department's Arson Unit and to Staff Sergeant Robert Gearhart and the other men and women of the 137th Explosive Ordnance Disposal office at Fort Sam Houston, TX, for their assistance with this article.
References:
U.S. Department of Defense, U.S. Air Force. Aerospace Munitions Officer Course 3200 Training Manual, 1966-67, Volume II. Montgomery: Extension Course Institute, Gunter Air Force Base, 1966.
Aerospace Munitions Officer Course Training Materials. Denver: Lowry Air Force Base, 1964.
Aircraft Explosive Items. Technical Manual. TO 11-1-34. 17 May 1968. Ogden: USAF, May 1968.
U.S. Department of Defense. U.S. Army. Antipersonnel Mine M18A1 and M18 (Claymore). FM 23-23. Washington: GPO, August 1966.
Explosives and Demolitions, FM 5-25. Washington: GPO, May 1967.
James Wogstad and Phil Friddell, "American Aircraft Bombs 1971-1974," Replica in Scale, spring/ summer 1974.
Mike Pickett is a San Antonio-based fire and safety consultant. He also teaches part time in the Fire Science Program at San Antonio College, where he was an associate professor from 1970 to 1995. Since 1970, he has worked with the San Antonio Fire Department. Previous articles in this series were published in September 1995 and September 1996.
