modern

The M60 Patton is the first main battle tank, built in the USA. Development of the M60 began in 1957. It was designed to counter the threat posed by Soviet T-54 and T-55 medium tanks, that were superior in all aspects to the US M48 medium tanks. First vehicles were built in 1959 and contract was awarded to Chrysler for a batch of 180 MBTs. Production commenced in 1960 and ended in 1987.

In terms of design the M60 is a further development of the M26, M46, M47 and M48 tanks. A number of components were carried over from the M48A2 medium tank. However the M60 featured significantly improved armored protection, more powerful armament and engine.

The M60 Patton main battle tank is armed with British L7 105 mm rifled gun. It was a standard NATO tank gun, used on contemporary tanks, such as French AMX-30 and German Leopard 1. The L7 gun was license-produced in the USA as the M68. This tank gun could be replaced in field conditions if necessary. The M60 tank could penetrate 120 mm of rolled homogenous armor at a range of 2 000 meters. A total of 60 rounds for the main gun of five types were carried.
http://www.military-today.com/tanks/m60_patton.htm