Composition B, colloquially Comp B, is an explosive consisting of castable mixtures of RDX and

TNT Trinitrotoluene (), more commonly known as TNT, more specifically 2,4,6-trinitrotoluene, and by its preferred IUPAC name 2-methyl-1,3,5-trinitrobenzene, is a chemical compound with the formula C6H2(NO2)3CH3. TNT is occasionally used as a reagen ...

. It is used as the main explosive filling in

artillery Artillery is a class of heavy military ranged weapons that launch munitions far beyond the range and power of infantry firearms. Early artillery development focused on the ability to breach defensive walls and fortifications during siege ...

projectiles,

rocket A rocket (from it, rocchetto, , bobbin/spool) is a vehicle that uses jet propulsion to accelerate without using the surrounding air. A rocket engine produces thrust by reaction to exhaust expelled at high speed. Rocket engines work entirely fr ...

land mine A land mine is an explosive device concealed under or on the ground and designed to destroy or disable enemy targets, ranging from combatants to vehicles and tanks, as they pass over or near it. Such a device is typically detonated automati ...

hand grenades A grenade is an explosive weapon typically thrown by hand (also called hand grenade), but can also refer to a shell (explosive projectile) shot from the muzzle of a rifle (as a rifle grenade) or a grenade launcher. A modern hand grenade ge ...

and various other

munitions Ammunition (informally ammo) is the material fired, scattered, dropped, or detonated from any weapon or weapon system. Ammunition is both expendable weapons (e.g., bombs, missiles, grenades, land mines) and the component parts of other weap ...

. It was also used for the explosive lenses in the first implosion-type

nuclear weapon A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission (fission bomb) or a combination of fission and fusion reactions ( thermonuclear bomb), producing a nuclear explosion. Both bom ...

s developed by the United States.''Atom Bombs: The Top Secret Inside Story of Little Boy and Fat Man'', John Coster-Mullen, 2003Nuclear Weapons FAQ section 8.1.1: The Design of Gadget, Fat Man, and "Joe 1" (RDS-1)
accessed August 10, 2009 The standard proportions of ingredients (by weight) are 59.5% RDX (

detonation velocity Explosive velocity, also known as detonation velocity or velocity of detonation (VoD), is the velocity at which the shock wave front travels through a detonated explosive. Explosive velocities are always faster than the local speed of sound in t ...

of 8,750 m/s) and 39.5% TNT (detonation velocity of 6,900 m/s),

phlegmatized A phlegmatized explosive is an explosive that has had an agent (a phlegmatizer) added to stabilize or desensitize it. Phlegmatizing usually improves the handling properties of an explosive (e.g. when munitions are filled in factories. Alfred N ...

with 1%

paraffin wax Paraffin wax (or petroleum wax) is a soft colorless solid derived from petroleum, coal, or oil shale that consists of a mixture of hydrocarbon molecules containing between 20 and 40 carbon atoms. It is solid at room temperature and begins to ...

. Most commonly it is described as 60/40 RDX/TNT with 1% wax added.

Properties

* Density: 1.65 g/cm³ * Velocity of

detonation Detonation () is a type of combustion involving a supersonic exothermic front accelerating through a medium that eventually drives a shock front propagating directly in front of it. Detonations propagate supersonically through shock waves with s ...

: 8,050 m/s

Use

Composition B was extremely common in western nations' munitions and was the standard explosive filler from early

World War II World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposing ...

until the early 1950s, when less sensitive explosives such as

Composition H6 __NOTOC__ Composition H6 is a castable military explosive mixture composed of the following percentages by weight: * 44.0% RDX * 29.5% TNT * 21.0% powdered aluminium * 5.0% paraffin wax as a phlegmatizing agent. * 0.5% calcium chloride H6 i ...

began to replace it in many weapons. M65 bombs from 1953 containing degraded Composition B were responsible for much of the damage in the 1967 USS ''Forrestal'' fire. Some

NATO The North Atlantic Treaty Organization (NATO, ; french: Organisation du traité de l'Atlantique nord, ), also called the North Atlantic Alliance, is an intergovernmental military alliance between 30 member states – 28 European and two No ...

-approved munitions suppliers such as

Mecar Mecar is a Belgian weapon and ammunition manufacturing company headquartered in Petit-Roeulx-lez-Nivelles, Hainaut Province. Mecar is responsible for creating weapons ranging from grenades to lightweight anti-tank cannons. The company was establi ...

have continued to use Composition B in their products. Composition B is related to Cyclotol, which has a higher proportion of RDX (up to 75%). IMX-101 is slowly replacing Comp B in US military artillery shells, and IMX-104 in mortar rounds and hand grenades.

Gallery

File:DM41 3.jpg, German DM41 fragmentation hand grenade labelled to indicate a filling of Composition B. File:USMC-100414-M-5241M-001.jpg, M107 projectiles. All are labelled to indicate a filling of "Comp B" and have fuzes fitted. File:Defense.gov photo essay 110715-N-KG738-278.jpg, A

shaped charge A shaped charge is an explosive charge shaped to form an explosively formed penetrator (EFP) to focus the effect of the explosive's energy. Different types of shaped charges are used for various purposes such as cutting and forming metal, ini ...

munition (marked to indicate a Composition B filling) used for various demolition purposes such as boring a hole for a cratering charge.

References

{{reflist Explosives

Properties

Use

Gallery

See also

References