The concept of "deep battle", which contained the doctrinal use of the Soviet heavy tank, was first theorized during the late twenties, then refined and eventually adopted by the Red Army Field Regulations in 1936. The tactical deep battle doctrine advocated for fast battle tanks (BT series ...
The USMC would eventually retire their M51s and follow the Army into adopting the newer M88 in 1977, outlasting the M103 by two years. Even now, both branches retain the M88 in its latest incarnation, the M88A2 Heavy Equipment Recovery Combat Utility Lifting Extraction System, otherwise known ...