Perhaps it was a metric many years ago which countries thought could be kept relatively unknown before everyone had cameras, instant communication, etc? The US

Perhaps it was a metric many years ago which countries thought could be kept relatively unknown before everyone had cameras, instant communication, etc? The US seems to be happy showing off the turret rotation speed of the M1 Abrams at public demos as shown in [1], [2], [3] and [4]. There is no rotation speed listed on the Wikipedia page for this tank but elsewhere on the Internet appears to state 9 seconds for full rotation, which appears to match up with what the videos show. I find it hard to believe there is much benefit if any in classifying turret rotation speeds, or for that matter, most other parts of a tank in 2021. The underlying technology is ancient and readily described in all manner of books and videos. The overwhelmingly important factor in tank warfare today would be whether another platform with better visibility of surrounds (UAV, satellite, etc) has communicated enemy positions to the tank crew. [1] https://www.youtube.com/watch?v=pKHcKEc_2Nc https://www.youtube.com/watch?v=pKHcKEc_2Nc [2] https://www.youtube.com/watch?v=UxLWb2AHLzw https://www.youtube.com/watch?v=UxLWb2AHLzw [3] https://www.youtube.com/watch?v=f5XUQ2beGfM https://www.youtube.com/watch?v=f5XUQ2beGfM [4] https://www.youtube.com/watch?v=u1mH-_h3_1Q https://www.youtube.com/watch?v=u1mH-_h3_1Q