Evolving from the M48 through the M60, the M-60A1 Patton tank was produced from 1962 through 1980. This newer variant featured a redesigned wedge-shaped turret with improved ballistic protection and a new mounting for the 105mm M68 main gun (modified from the excellent British L7 with a vertical sliding breech block), which could fire HE, Frag, AP, and HEAT rounds. Additional armament consisted of a coaxially mounted 7.62 mm M73 machine gun and a 12.7 mm M85 machine gun mounted in the commanders cupola. Further improvements consisted of increased armor thickness on the glacis and hull sides, as well as the installation of shock absorbers at the first two and last roadwheel stations. Powered by the improved 643 hp Continental AVDS-1790-2A V-12 twin turbo diesel engine coupled to the Allison CD-850-6A powershift cross-drive transmission, the tank weighed 58 tons and was served by a crew of four -- commander, gunner, loader, and driver. This vehicle became the main battle tank fielded by the US Armed forces through the 1960s into the early 1970s.
The ultimate development of the M-60A1 was the M-60A1 RISE (RISE= Reliability Improvements for Selected Equipment). These were rebuilt M-60A1s, with added passive starlight scopes for the driver, gunner and commander, eliminating the need for the bulky IR projector above the main gun. Other improvements included the Continental AVDS-1790-2C engine, which helped to boost engine power. A battery of smoke dischargers was also added to either side of the turret, like the set-up on the Chieftain tank. These vehicles were quickly supplied to frontline units overseas, such as in Germany, by early 1979.
Deployed to Operation Desert Shield in 1990, the United States Marines Corps' main battle tank was retrofitted with explosive reactive armor (ERA) tiles to further increase crew protection. During Operation Desert Storm, the 1st Marine Expeditionary Force fielded 210 M60A1s to support the liberation of Kuwait, destroying over 100 Iraqi T-55/62/72 & Type 69-II tanks (and losing only one to anti-tank mines).