It looks like there is a definite less need for speed for stopping power as the bullet gets larger around, and heavier will have more ( please insert correct term) I would call it energy.
Angus - be advised that 'some' here at the Fire don't believe that FPE is real or don't believe it's important.
Maybe ? I'm just old skool having 'learnt' during the 70s. & 80s about reloading, shooting, & killing. But I believe that no work gets done without 'energy'.
To illustrate my point, what happens IF we flip a bullet into the side of an animal ? We may startle or spook it, but there is no damage.
OTOH, if that same bullet is propelled at a mere 1000 fps, WORK gets done enuff to injure (damage) or kill the animal.
Enuff E is required to produce (work) lethal damage.
That's an effort to illustrate the point in layman's terminology.
