The Davy Crockett consisted of an XM-388 projectile launched from either a 120-millimeter (XM-28) or 155-millimeter (XM-29) recoilless rifle (the 120 millimeter version is shown above). This weapon had a maximum range of 1.24 miles (120 millimeter) to 2.49 miles (155 millimeter). The XM-388 casing (including the warhead and fin assembly) weighed 76 pounds, was 30 inches long and measured 11 inches in diameter (at its widest point).

The W54 warhead used on the Davy Crockett weighed just 51 pounds and was the smallest and lightest fission bomb (implosion type) ever deployed by the United States, with a variable explosive yield of 0.01 kilotons (equivalent to 10 tons of TNT, or two to four times as powerful as the ammonium nitrate bomb which destroyed the Alfred P. Murrah federal building in Oklahoma City on April 19, 1995), or 0.02 kilotons-1 kiloton. A 58.6 pound variant—the B54—was used in the Special Atomic Demolition Munition (SADM), a nuclear land mine deployed in Europe, South Korea, Guam, and the United States from 1964-1989.

The Davy Crockett was deployed with U.S. Army forces from 1961 to 1971. Between 1956 and 1963, 2,100 were produced at an estimated cost (excluding the warhead) of $540 million (in constant 1996 dollars). The weapon's non-nuclear components were manufactured at the Rock Island Arsenal in Rock Island, Illinois. The W54 warhead was designed at the Los Alamos Scientific Laboratory (now the Los Alamos National Laboratory) and built by the Atomic Energy Commission.

Stockpiled W54 warheads were test fired at the Nevada Test Site on July 7 and 17, 1962, during the Little Feller II and Little Feller I shots. In Little Feller II on July 7, the warhead was suspended on cables about three feet above the ground (yield was 22 tons). In Little Feller I on July 17, a Davy Crockett was fired from a stationary 155 millimeter launcher (in tandem with simulated battlefield manuevers under Operation IVY FLATS) and detonated about 20 feet above the ground at a distance of 9,357 feet (1.7 miles) from the launch point (yield was 18 tons). This test, the last atmospheric detonation at the Nevada Test Site, was observed by Attorney General Robert F. Kennedy and presidential adviser General Maxwell D. Taylor. Footage of Operation IVY FLATS was declassified by the Department of Energy on December 22, 1997.

Sources: U.S. Nuclear Weapons Cost Study Project; Thomas B. Cochran, William M. Arkin, Milton M. Hoenig, U.S. Nuclear Forces and Capabilities, Volume I, Nuclear Weapons Databook (Cambridge, Massachusetts: Ballinger Publishing Company, 1984), pp. 60, 311; Robert Standish Norris and Thomas B. Cochran, "United States Nuclear Tests: July 1945 to 31 December 1992," (Washington, D.C.: Natural Resources Defense Council, 1 February 1994), NWD-94-1, p. 35; Chuck Hansen, U.S. Nuclear Weapons: The Secret History (New York: Orion Books, 1988), pp. 197-198; Ted Nicholas and Rita Rossi, U.S. Historical Military Aircraft and Missile Data Book (Fountain Valley, California: Data Search Associates, 1991), pp. 3-95, 3-101; U.S. Department of Energy.

Credit: National Archives

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Nuclear Weapons - Misc Facts This page holds a few misc. facts about nuclear weapons that may be surprising to many. Recent Terrorist Related Information ("Suitcase Nukes") The US produced, and for many years deployed "Atomic Demolition Munitions." The Medium Atomic Demolition Munition (MADM) produced 1-15 kilotons of yield, and weighed 400 pounds. The Special Atomic Demolition Munition (SADM)  yielded .01-1 kilotons and weighed only 163 pounds.   See here and here. The smallest nuclear weapon the US produced was the "Davy Crockett"  - a recoilless rifle round. It weighed about 51 pounds, was 16 inches long and 11 inches in diameter. It produced a variable yield of up to 1 kiloton. See here. An excellent discussion of this issue is here. The Soviets supposedly produced "suitcase nukes" and there is no reason to doubt this assertion. Former Soviet General Ledbed has asserted that a number of these are not accounted for. There are reasons, however, to doubt his assertions given his political position. General Observations   Most information comes from "The Effects of Nuclear Weapons" - 1964 - US DOD There was no significant fallout in the vicinity of the Hiroshima and Nagasaki bombings. All radiation injuries were a result of immediate (first 1 minute) radiation. The only cases of significant fallout exposure (as of 1964) to individuals (other than globally ) was in the Marshall Islands after a U.S. test. The short term effects were skin "burns." As of 1964, no long term effects were known, although a slight excess cancer rate would be expected based on modern knowledge. Almost all radioactivity in fallout - even in a ground burst - comes from the fission products themselves or transmutation of parts of the weapon. Thus air bursts and ground bursts produce approximately the same amount of radioactive products. However, ground bursts cause much more of the radioactive debris to be deposited within a fallout pattern, rather than distributed (and accordingly diluted and decayed) across the entire planet. In Hiroshima, there was a 50% survival rate .12 miles (200 meters) from ground zero. The bomb went off at 1850 feet above ground zero with a yield of about 20kt. Concrete structures at ground zero survived. In Hiroshima, there was only one known case of burst eardrums among the survivors.   More Technical Information Blast Effects The blast effect is primarily determined by the "overpressure" - given in english units in PSI. This effect at any distance is proportional to the cube root of the weapons yield. Thus a 20 megaton bomb, which is large by today's standards, will affect only 10 times the radius of a 20 kiloton bomb - which was the yield at Hiroshima. A human being can withstand up to about 35PSI of peak overpressure from a nuclear blast (1% fatality rate).  Your mileage may vary. Thus a human will almost always survive the blast overpressure at approximately the following distances (slant range) from a blast according to the following table: Distance From Blast to Survive Blast Wave Yield Distance (mi) Distance (km) Comments 20 kT .35 .56 Hiroshima and Nagasaki 600 kT 1.1 1.8 Typical Strategic US Nuke 20 MT 3.5 5.6 Very Big Bomb The blast wave can, however, pick people up and throw them. For a 165 pound standing person to be thrown at 20 feet per second, the following table shows the distance from the blast: Distance From Blast to be Thrown at 20 fps Yield Distance (mi) Distance (km) 20kT 1.06 1.75 600kT 4.1 6.6 20MT 16.8 27 Max Wind at Distance from Blast Yield 1 mi 1.6 km 3 mi 4.8 km 10 mi 16 km 30 mi 48 km 20kT 200 mph 89 mps 47 mph 21 mps 5 mph 2 mps ~0 600kT 1000 mph 447 mps 210 mph 94 mps 51 mps 23 5 mps 2 20MT off scale 1200 mph 536 mps 195 mph 87 mps 47 mph 21 mps The greatest danger from the blast wave comes from destruction of structures and the conversion of objects into missiles. The following tables gives the destruction distance from various yields for a few kinds of structures: Window Breakage Yield Distance (mi) Distance (km) 20kT 3.2 5.1 600kT 10 16 20MT 32 51 Wood-frame Building Destruction Yield Distance (mi) Distance (km) 20kT 1.5 1.9 600kT 4.8 7.7 20MT 15 19 Multi-story Brick Yield Distance (mi) Distance (km) 20kT 1. 1.6 600kT 3.0 4.8 20MT 10 16 Multi-story Reinforced Concrete Offices Yield Distance (mi) Distance (km) 20kT .5 .81 600kT 1.3 2.1 20MT 5 8.1

• A ground burst produces a crater. The following table shows crater sizes:

  Crater Sizes
  Yield	Width (feet)	Width (m)	Depth (feet)	Depth (m)
  20kT	633	193	80	24
  600kT	2112	643	211	64
  20MT	7392	2253	792	241

References

Nuclear Weapons Archive and FAQ: http://fas.org/nuke/hew/.