Since the early 1960s U.S. defense ordnance workers and contractors had been working on a new main battle tank design to replace the M60 tank. A larger caliber gun and better protection for the crew were desired.

Since the early 1960s U.S. defense ordnance workers and contractors had been working on a new main battle tank design to replace the M60 tank. A larger caliber gun and better protection for the crew were desired.