Originally Posted by Hal:
Just for conversation's sake,,
Let's say you were handed a round of ammunition.
You look at the base and see that it's a .357Mag case.
Other than what a visual inspection shows, you can't have any other information about that round - except -
It's muzzle energy
It's muzzle velocity.
Armed with that number, and, based on your experience usinng the caliber in question,,,
Which would you choose to make the most educated guess as to how effective that round would be?
That's an interesting question- I don't know that I could since it is not possible to determine the KE of either round without knowing the bullet's weight or velocity.
For instance, both of the .357 Mag rounds could be marked as having a KE of 583 fpe which means that one could be a 125 gr. bullet at 1450 fps and the other a 158 gr. JHP at 1290 fps- or they could be of other weights at other muzzle velocities that's give me that number. Both would have 583 fpe of KE, but not knowing the weights or the velocities of each, I'd be making the choice in a relative vacuum.
Forced to decide, I'd heft them separately and go with the heaviest of the two since momentum is the best measure of a bullet's ability to penetrate soft tissue.
Conversely, if I were selecting a round to defeat a thin, hard barrier like a sheet of mild steel, I'd opt for the lighter, faster one since kinetic energy is the best measure of a bullet's ability to penetrate/defeat those types of barriers.