Because it was originally intended as a measure for full patch or steel jacketed non expanding bullets, I give it little attention with today's modern expanding bullets which are well designed and or homogeneous which again, deflates the argument when talking penetration.
John
As I was growin up in the handloading practice, we DID NOT have the monos of today. We had N P, Bitterroot, and only a couple more that I knew about.
AGW hits the nail on the head.
Even at that, S D is a no. that can show 'relativity' between bullet 'shapes'(length/dia).
Early on "GIVEN the same construction" (IMPORTANT) S D served a good purpose to indicate how different bullets---SHOULD---penetrate compared to each other.
AS AGW says, many modern bullets have erased that need.
Jerry
