Shortly after the development of the first atomic bombs, the USA and the USSR began investigations into devices with limited yield for sub-strategic and tactical situations. This developed into short-range delivery systems and low-yield warheads from the late 1950s onwards, including landmines, depth charges, torpedoes, demolition munitions and artillery shells.
US Nuclear Artillery
The first artillery test was on May 25, 1953 at the Nevada Test Site (Operation Upshot-Knothole, Shot GRABLE). A 280mm shell with a gun-type fission warhead was fired 10,000 m and detonated 160 m above ground with an estimated yield of 15 kilotons. The W-9 warhead (80 produced, retired 1957) was followed by the W-19 (280mm) and the W-48 — a 155mm shell weighing just 58 kg with a yield of 72 tons TNT equivalent.
The W-33 for 203mm shells was the most widely produced, with around 2,000 warheads manufactured from 1957-65, yielding 5 to 40 kt. In 1991 the US unilaterally withdrew approximately 1,300 nuclear shells from Europe, and Russia responded in kind in 1992.
Davy Crockett Nuclear Bazooka
The Davy Crockett was deployed by the United States in West Germany from 1961-1971. The smallest missile-launched nuclear weapon ever built, it carried a variable 10-250 tonne W-54 fission warhead. It could be launched from either an M28 (102mm, range 1.24 miles) or M29 (155mm, range 2.5 miles) recoilless rifle, operated by a 3-man team.
The Davy Crockett could kill every man in an advancing army and irradiate the area for up to 48 hours. It was tested on July 7, 1962 (LITTLE FELLER II) and July 17 (LITTLE FELLER I, the last atmospheric test at the Nevada Test Site). 400 Mk-54 warheads were produced from 1961-65.