Original Item. Only One Available. This is an interesting WWI-era Cooper-pattern aerial fragmentation bomb, a design developed in Britain and used extensively during the First World War. It retains its distinctive pear-shaped metal body, removable nose cap, suspension lug, and wooden tail assembly with four sheet-metal stabilizing fins. The Cooper pattern was also adopted by the United States, where it became associated with the 25-pound Mk III fragmentation bomb designation. [26" long × ~5" diameter]

The bomb has a substantial yellow-painted finish covering the body, nose, and tail assembly. A single metal suspension lug projects from the casing, while the nose is fitted with a cylindrical protective cap that can be unscrewed. The propeller-type arming vane normally associated with the original Cooper fuze arrangement is absent. At the opposite end, the wooden tail sections remain fitted with four metal fins, secured by a central threaded rod and retaining nut.

Of particular interest are the black identification markings on the body. The principal stencil reads "BOMB FRAG", with a worn designation beneath that appears to read "MK 3", potentially referring to the American Mk III fragmentation bomb designation.

Additional red-painted inscriptions include "60 lb." and a marking appearing to read "WW1". These appear to be later identification or display markings, although their date and origin are unknown. The 60-pound inscription should not be taken as the bomb's weight.

The bomb remains in good overall condition, retaining its distinctive shape and a substantial amount of yellow-painted finish. There is widespread surface wear, including scratches, scattered paint loss, localized oxidation, and darkening around the nose and body joints. The metal tail fins remain present, with chipped paint, exposed metal, and some edge wear. The wooden tail components show age-related discoloration and wear, while the rear fastening hardware has developed oxidation and is not fully secure. The black stencil remains largely legible despite its worn appearance.

Unloaded or dummy grenades, artillery shell casings, and similar devices, which are cut or drilled in an BATF-approved manner so that they cannot be used as ammunition components for destructive devices, are not considered NFA weapons. This example is in total compliance and is NOT AVAILABLE FOR EXPORT.

Historical Context

The Cooper aerial bomb was developed in Britain during the First World War, when military aviation was expanding rapidly beyond its initial reconnaissance duties. By 1917, British aircraft were increasingly employed in attacks against enemy troops, transportation routes, and other ground targets. The Cooper bomb became an important weapon for these operations, particularly among aircraft of the Royal Flying Corps (RFC) and Australian Flying Corps (AFC).

The British Cooper High-Explosive Bomb, commonly designated the 20-pound Cooper, was introduced into service around 1917. Its heavy metal casing was designed to break into fragments upon detonation, making it suitable for use against exposed personnel and lightly protected targets. The standard pattern weighed approximately 24 pounds when filled, including a casing weighing about 20 pounds and an explosive charge of approximately four pounds, generally consisting of Amatol.

The bomb was fitted with an impact-operated nose fuze incorporating an airflow-operated arming mechanism. After release from the aircraft, a small propeller rotated in the airstream, allowing the internal mechanism to arm during descent. The protective nose cover was used during storage and transportation. The wooden tail and four metal fins provided stabilization in flight, helping the bomb descend in the intended orientation.

Cooper bombs were carried externally on aircraft bomb racks and could be released individually or in groups during attacks. They were particularly suited to the developing practice of tactical aerial bombardment, in which aircraft operated against troops and military positions near the front lines. By the final years of WWI, the increasing use of such weapons had made aerial attacks an established component of battlefield operations.

The design also entered American service following the United States' entry into the war in April 1917. The American military adopted British aerial ordnance during the conflict while developing its own manufacturing and standardization programs. Under the American designation system, the Cooper-pattern bomb became associated with the 25-pound Mk III fragmentation bomb, retaining the characteristic pear-shaped body and tail-stabilized arrangement.

The American Mk III designation remained in ordnance inventories after the war, although the weapon was eventually superseded by newer fragmentation-bomb designs. By the Second World War, the Mk III was regarded as obsolete, having belonged to an earlier generation of aerial weapons developed around the time of the First World War.

The Cooper design represents an important stage in the development of purpose-built aircraft ordnance, when specialized fragmentation bombs, mechanical arming systems, and standardized aircraft bomb carriers were becoming established features of military aviation.

Totally inert, cannot be converted to an explosive device, not available for export. This item is completely legal within the USA. International Military Antiques, Inc observes all Federal, State and Local laws. Everything for sale on ima-usa.com is completely legal to own, trade, transport and sell within the United States of America.

All deactivated ordnance sold by IMA, Inc is engineered to be inoperable according to guidelines provided by the US Bureau of Alcohol, Tobacco, Firearms and Explosives (BATF).