Regardless of bullet design, the the highest SD for a given caliber will give you the deepest penetration.
JD338
This is a very interesting comment. Do you all remember the Speer 275 grain .338 caliber bullet that was the choice of Elmer Keith, especially for use in his .338/378 KT?
That Speer bullet "had" (it is discontinued) a Sectional Density of .348 which is very high for the caliber, any caliber in fact.
If SD had any value for soft point or expanding bullets, it has been proven conclusively, that SD was not useful in determing the penetration ability for a bullet simply because SD is drastically reduced upon impact, largely becoming irrelevent.
SD is theory and marketing jibberish only, it has proven worthless by the innovation of contemporary construction.
The reality is, that SD was originally used as a mathematical formula for comparing solid (FMJ) bullets in determining suitability for large dangerous game. It has no qualifying benefit when applied to expanding bullets and a Failsafe weighing 230 grains or a TSX weighing 225 even though nearly 20% less in bullet weight, would out penetrate anything the old Speer could do and shoot a whole lot flatter getting there.
No, forget SD, that will lose every argument, as is should have been killed of as a writer topic a long time ago.
Please keep these coming and I will give you my summary next week. The information you are providing is extremely valuable to the readers so please do not fall off this one.
