Tank origin

During the latter part of the Cold War, the U.S. developed the Advanced Tank Cannon System (ATACS), an upgrade system that included the XM291 140mm smoothbore gun. This system was mounted to an M1 Abrams testbed to create the experimental vehicle CATTB nicknamed “Thumper.” Although it didn’t reach production, the experimental vehicle, CATTB was used to test and develop a number of weapon and defensive systems..