Jan Fischer, American Soldier In His Military Life

As the speed of technological advances accelerated in civilian applications, so too warfare became more industralised. The newly invented machine gun and repeating rifle redefined fire power on the battlefield and, in part, explains the high casualty rates of the American Civil War. The next breakthrough was the conversion of artillery parks from the muzzle loading guns to the breech loading guns, and in particular the highly mobile, recoilless, field-gun, the French Soixante-Quinze, in the late 19th century.
The development of breech loading had the greatest effect on naval warfare, for the first time since the Middle Ages altering the way weapons are mounted on warships, and therefore naval tactics, now divorced from the reliance on sails with the invention of the internal combustion. A further advance in military naval technology was the design of the submarine and its weapon, the torpedo.
During World War I the need to break the deadlock of the trenches saw the rapid development of many new technologies, particularly the tanks and military aviation. Military aviation was extensively used, and particularly the bombers during the World War II, which marked the most frantic period of weapons development in history. Many new designs and concepts were used in combat, and all existing technologies were improved between 1939 and 1945.
During the war significant advances were made in military communications through use of radio, military intelligence through use of the radar, and in military medicine through use of penicillin, while in the air the missile, jet aircraft and helicopters were seen for the first time. Perhaps the most infamous of all military technologies was the creation of the atomic bomb, although the effects of radiation were unknown until the early 1950s. Far greater use of military vehicles had finally eliminated the cavalry from the military force structure.