After BT-2, the next step in the evolution of Soviet high-speed tanks was BT-5. This tank received a new turret and a more powerful 45 mm cannon. The design of the BT-7 has changed more seriously. This tank had a new welded hull and a new engine. In more detail about the history of BT-5 and BT-7 and about the differences between these tanks in his new video tells Peter Samsonov.