COMMON NAME – Composition C
TYPE – High explosive mixture
DATE FIRST USED AS AN EXPLOSIVE – 1942
COUNTRY OF ORIGIN – Great Britain
COMPOSITION – 88.3% RDX, 11.1% Plasticizing oil, 0.6% lecithin
DENSITY – 1.49 g per ml
NORMAL STATE – Malleable solid
PHYSICAL APPEARANCE/COLOR – White to brown solid
INITIATION – 0.25 g Lead Azide, 0.11 g Tetryl booster
SENSITIVITY – Less sensitive to impact than TNT, no detonation when struck with 7.62mm (30 cal) rifle bullet
STABILITY – Non-reactive to metals, unstable over time, heat causes plasticizing oil to leach out
DETONATION VELOCITY – 7,925 m/s (26,000 fps)
RE FACTOR (BRISANCE) [TNT=1.0] – 1.27
TOXICITY – Toxic if ingested, Burning releases toxic fumes
MELTING POINT – 0 to 40o C. (32 to 104o F.) remains plastic, 40o C (104o F.) and above, exudes plasticizing oil
IGNITION POINT – 285o C. (545o F) Detonates
FREEZING POINT – 0o C (32o F.) becomes brittle
SOLUBILITY – Relatively insoluble in water
APPLICATIONS – PRINCIPLE USES – Flexible, malleable, plastic explosive for demolition
Composition C was the first plastic explosive supplied by Great Britain to the US Troops stationed in England. Made up of a mixture of 88% RDX, 11.4% Oil, and 0.6% Lecithin, Composition C became the first plastic explosive to see issue in the US Military. The basic formulation of RDX and oil was used by a number of forces during World War II, including Great Britain, Germany, Japan, and the United States. The plastic, flexible nature of Composition C allows it to be formed around targets which increased the efficiency of the explosive as a cutting agent. The flexibility makes the explosive particularly effective against steel targets such as railroad rails and I-Beams. This plastic nature was taken advantage of when large numbers of simple demolition charges known as Hagensen Packs were prepared to blast through the obstacles blocking the D-Day landings on Utah and Omaha beaches at Normandy during the amphibious phase of Operation Overlord. The formulation of Composition C has weaknesses, particularly one of the explosive leaching out oil when hot. This leaching causes a buildup of sensitive RDX crystals in the charge and prevented Composition C from seeing much use in the areas of the Pacific Theater during World War II. This characteristic was improved in later formulations of Composition C2 in 1943, Composition C3 in 1944, and Composition C4 in 1949.
