In November 1956, Hungarian rebels drove a captured Soviet T-54A into the courtyard of the British embassy in Budapest, and military attache Lieutenant Colonel Noel Cowley measured its armor and gun. His data showed the West’s 20-pounder gun could not defeat the T-54’s front, making the U.S. M48 obsolete, while the replacement T95, with its X-shaped vapor cycle engine, kept breaking down. The XM60 program began in 1957 with testing and production running at once. Engineers rejected a 120mm gun whose two-piece ammunition cut fire to four rounds a minute, chose the 105mm M68 based on the British L7 for seven rounds a minute, and dropped siliceous-cored glass armor in 1958 for sloped rolled steel. More than 15,000 were built.

The M60 merged the medium and heavy tank roles into the main battle tank, and by 1963 the Marines had replaced their M103 heavy tanks with it. The 1962 M60A1 added a long needle-nose turret holding 63 rounds. The M60A2 “Starship,” built from 1973 to 1975, carried a 152mm gun launcher for wire-guided missiles that proved unreliable, and the M60A3 added a laser rangefinder, ballistic computer and thermal sight. Israel used its Magach versions in the 1973 Yom Kippur War and fitted explosive reactive armor by the 1982 Lebanon War. The U.S. retired the M60 in 1997, and over 20 nations still use modified versions.

• 1959 Ordnance Technical Committee minutes named it Tank, Combat, Full Tracked, 105mm Gun, M60, so it was never officially a Patton.
• The tall M19 cupola let the commander fire a .50 caliber machine gun under armor but made the tank a bigger target.
• In Grenada in 1983, Marine M60A1s with Israeli reactive armor pushed inland to rescue Navy SEALs at the Governor General’s mansion.
• In the 1991 Gulf War, Marine M60A1s used thermal sights to find Iraqi T-72s through smoke from burning oil wells.
• Iran’s Zulfiqar mounts a Russian 125mm smoothbore, and General Dynamics pitched the M60-2000 with an Abrams turret on an M60 hull.