General - purpose bomb A general - purpose bomb is an air - dropped bomb intended as a compromise between blast damage , penetration , and fragmentation in explosive effect . Characteristics . General - purpose ( GP ) bombs use a thick - walled metal casing with explosive filler ( typically TNT , Composition B , or Tritonal in NATO or United States service ) composing about 50 % of the bomb ' s total weight . The British term for a bomb of this type is " medium case " or " medium capacity " , abbreviated to MC . The GP bomb is a common weapon of fighter bomber and attack aircraft because it is useful for a variety of tactical applications and relatively cheap . General - purpose bombs are often identified by their weight ( e . g . , 500 lb , 250 kg ) . In many cases this is strictly a " nominal " weight , or " caliber " , and the actual weight of each individual weapon may vary depending on its retardation , fusing , carriage , and guidance systems . For example , the actual weight of a U . S . M117 bomb , nominally 750 lb ( 340 kg ) , is typically around 820 lb ( 374 kg ) . Most modern air - dropped GP bombs are designed to minimize drag for the carrier aircraft . In low - altitude attacks , there is a danger of the attacking aircraft being caught in the blast of its own weapons . To address this problem , GP bombs are often fitted with " retarders " , parachute s or pop - out fins that slow the bomb ' s descent to allow the aircraft time to escape the detonation . GP bombs can be fitted with a variety of fuse s and fins for different uses . One notable example is the " daisy cutter " fuse used on Vietnam - era American weapons , an extended probe designed to ensure that the bomb would detonate on contact ( even with foliage ) rather than burying itself in earth or mud , which would reduce its effectiveness . ( Note : this was not the first use of such devices . As early as WWII , the Luftwaffe was utilizing extended - nose fuses on bombs dropped by Stuka dive - bombers and other aircraft , for the exact same reason . A blast several feet above the ground in many times more effective and has a far greater radius than one that is delayed until the bomb is below the surface . ) GP bombs are commonly used as the warheads for more sophisticated precision - guided munitions . Affixing various types of seeker and electrically controlled fins turns a basic ' iron ' bomb into a laser - guided bomb ( like the U . S . Paveway series ) , an electro - optical guided bomb , or , more recently , GPS - guided weapon ( like the U . S . JDAM ) . The combination is cheaper than a true guided missile ( and can be more easily upgraded or replaced in service ) , but substantially more accurate than an unguided bomb . Modern GP bombs . Modern American GP bombs : the Mark 80 series . During the Korean War and Vietnam War the U . S . used older designs like the M117 and M118 , which had an explosive content about 65 % higher than most contemporary weapons . Although some of these weapons remain in the U . S . arsenal , they are little used and the M117 is primarily carried only by the B - 52 Stratofortress . The primary U . S . GP bombs are the Mark 80 series . This class of weapons uses a shape known as Aero 1A , designed by Ed Heinemann of Douglas Aircraft as the result of studies in 1946 . It has a length - to - diameter ratio of about 8 : 1 , and results in minimal drag for the carrier aircraft . The Mark 80 series was not used in combat until the Vietnam War , but has since replaced most earlier GP weapons . It includes four basic weapon types : Vietnam service showed the Mk 81 " Firecracker " to be insufficiently effective , and it was withdrawn from U . S . service . However , recently , precision - guided variants of the Mk 81 bomb have begun a return to service , based on U . S . experience in Iraq after 2003 , and the desire to reduce collateral damage compared to Mk 82 and larger bombs ( e . g . , when attacking a single small building in a populated area ) . Since the Vietnam War , United States Navy and United States Marine Corps GP bombs are distinguished by a thick ablative fire - retardant coating , which is designed to delay any potential accidental explosion in the event of a shipboard fire . Land - based air forces typically do not use such coatings , largely because they add some 30 lb ( 14 kg ) to the weight of the complete weapon . Fire is less a danger in a land - based facility , where the personnel can be evacuated with relative ease , and the building be the only loss . At sea , the crew and munitions share a facility ( the ship ) , and thus are in much more danger of fire reaching munitions ( which tend to be more closely packed , due to space limitations ) . Also , where losing a munitions storage building on land is far cheaper than sacrificing an entire naval vessel , even if one could easily evacuate the crew . All Mk80 bombs have both nose and tail fuse wells and can accept a variety of fuses . Various nose and tail kits can be fitted to adapt the weapon for a variety of roles . In the Mk 80 series bomb bodies is also used in the following weapons : Smart bomb kits . Dumb Mk 80 bombs could be converted to " smart bombs " with attached kits : Modern British GP bombs . The British describe general - purpose bombs as medium capacity ( MC ) bombs . The principal modern British bombs are 540 lb ( 245 kg ) and 1 , 000 lb ( 454 kg ) , with a wide variety of fin , fuze , and retarder options . The 1000 lb MC was developed from 1942 to replace the existing 1000 lb GP ( General Purpose ) bomb . Initially using most of the components of the 1000 lb GP it was decide to give it a new tail and was built with a half - inch thick wall . Fillings could be Amatex , Amatol , Minol , RDX and others . Actual weight was around 1020 lb ( 464 kg ) . It was introduced to service in 1943 and about a quarter of a million produced by the end of the war . Soviet / Russian GP bombs . The Russian term for general - purpose bomb is " fugasnaya aviatsionnaya bomba " , abbreviated FAB and followed by the bomb ' s nominal weight in kilograms . Most Russian iron bombs have circular ring airfoils rather than the fins used by Western types . In 1946 the Soviet Union developed a series of freefall bombs in four sizes 250 kg ( 550 lb ) , 500 kg ( 1 , 100 lb ) , 1 , 500 kg ( 3 , 300 lb ) , and 3 , 000 kg ( 6 , 600 lb ) and sharing a single nose and a single tail fuze . The bomb could be dropped from up to 12 , 000 m ( 40 , 000 ft ) and up to 1 , 000 km / h ( 625 mph ) . The original , 1946 - series bombs had poor ballistic characteristics at supersonic speed , and their construction was fragile . As an interim measure , upgraded versions of the bombs were built with thicker walls and no nose fuze . The thick - walled version of the bombs were built until 1956 . The 1954 series of high - drag bombs was built in six sizes : 250 kg ( 550 lb ) , 500 kg ( 1 , 100 lb ) , 1500 kg ( 3 , 300 lb ) , 3 , 000 kg ( 6 , 600 lb ) , 5 , 000 kg ( 11 , 000 lb ) , and 9 , 000 kg ( 20 , 000 lb ) . The smaller ( less than 3 , 000 kg ) bombs had a single nose and a single tail fuze , while the larger weapons shared a single nose fuze and two base fuzes . The FAB - 9000 ( 9 , 000 kg / 20 , 000 lb ) weapon was roughly comparable to the wartime Grand Slam bomb . It was used by Russian aircraft designers as a substitute for early nuclear weapon s when determining the size and clearances of bomb bays . In 1962 a new series of streamlined , low - drag bombs was introduced , designed for external carriage by fighter - bomber aircraft rather than in internal bays . They come in only two sizes , 250 kg ( 550 lb ) and 500 kg ( 1 , 100 lb ) . Both bombs have a single nose fuze . Both the 54 and 62 series designs remain in use . The most common of these are the FAB - 100 , FAB - 250 , FAB - 500 , FAB - 750 , and FAB - 1000 , roughly corresponding to the U . S . Mark 80 series . These have seen widespread service in Russia , Warsaw Pact nations , and various export countries . Larger bombs with less streamlined shapes also remained in the Soviet arsenal , primarily for use by heavy bombers . In the Iran – Iraq War , FAB - 5000 ( 5 , 000 kg / 11 , 000 lb ) and FAB - 9000 ( 9 , 000 kg / 20 , 000 lb ) bombs were dropped by Iraqi Air Force Tupolev Tu - 22 bombers , generally against large , fixed targets in Iran . In Afghanistan in the 1980s , Soviet Tupolev Tu - 16 and Tupolev Tu - 22M bombers used massive FAB - 1500 , FAB - 3000 and FAB - 9000 bombs to devastating effect during the Panjshir offensives . French GP bombs . France ' s GP bombs , marketed by Matra and built by the Société des Ateliers Mécanique de Port - sur - Sambre ( SAMP ) are made in a variety of types with nominal weights from 50 kg ( 110 lb ) to 1 , 000 kg ( 2 , 205 lb ) . The most common are the 250 kg ( 550 lb ) EU2 and T25 , 400 kg ( 882 lb ) T200 , and 1 , 000 kg ( 2 , 205 lb ) BL4 . Other nations . Other countries , including Pakistan , Brazil , Chile , Israel , India , Portugal , Romania , Azerbaijan , South Africa , Spain , and Sweden , manufacture their own bombs , most of which are either licensed version of the U . S . Mark 80 series or close copies .