Development Obscured

Two postwar publications, one by osrd’s veterans and one by Army historians, differ on the key players and events in their joint wwii recoilless project, and a prior mortar one. The osrd’s famed Dr. C. Hickman was the key player in both projects, despite the Army’s account. In 1942–1944, the range of Army’s 4.2-inch (107mm) Mortar (4.2M), was increased, mostly by improving its inner ballistics such as upgrading the propellant charge. To fire directly at bunkers, unfeasible with a mortar, an idea was raised for a recoilless version, based on a nozzle replacing the 4.2M barrel’s rear cap. By 1944, the 4.2-inch Recoilless-Rifle (4.2rr) was ready. In the osrd’s account, most likely written by Hickman himself, Hickman was first to raise the recoilless idea and the appropriate 4.2M changes. Yet in the Army’s account, an officer raised the recoilless idea while Hickman led the 4.2rr detailed design. In the same account Hickman was missing in the story of the 4.2M range increase. Supporting data for Hickman, not appearing in either source, helps clarify the history, specifically Hickman’s patents filed in 1944–1945 on inventing the 4.2rr and improving mortar propellants based on his role in the 4.2M. After the war he received a presidential award for his wwii inventions such as as recoilless, and his 4.2rr/4.2M patents were eventually approved. Being asked to assist Sandia Laboratories in New Mexico on missile development in 1950, he there filed a patent in 1952 (assigned to the Army), to improve the 4.2rr projectile penetration, even though the 4.2rr was retired in 1947. The patent is likely an outcome of Hickman’s 1950–1952, 4.2rr upgrade requested by the Army and probably for use in Korea, due to the faulty 105-mm rr. It is also proposed that Hickman and his work on the 4.2rr for the Army, may have inspired Sandia to develop recoilless in the mid-1950s, specifically the 120 mm and 155 mm short range, light recoilless guns for firing small nuclear warheads that came to be known as the Davy Crockett system. They resembled the 4.2rr and accepted by the Army over other options in 1958, Hickman’s last year for Sandia.