The US military has fielded the Abrams tank for more than 40 years.
General Dynamics, which builds the Abrams, recently unveiled an updated version of the M1.
The diet M1General Dynamics' AbramsX tank.
US soldiers do maintenance on an Abrams tank in Germany in August 2017.
"If you keep the armor protection at a very minimal level, that's how we achieve the 60 tons," Reese said.