After many decades of reloading and hunting I am of the opinion that SD in and un its-self is worthless.
For example I believe a 7mm 120gr Barnes TTSX with a SD of .213 will out penetrate a 180 Berger 7mm with a SD of .319. What is important is the Post Expansion (PE) SD and the Berger looses so much weight and has a larger diameter which gives it a lower PE SD than the Bartnes 120.
Any Comments.