Not a user of the FPE in my caliber determinations here, either. Making a hole through vital parts and motation bones is most reliable predictor of effect. The only advantage rifle bullets have is - sometimes - (velocity needs to be pretty danged high) hydraulic overload effects far from the initial bullet strike area and path. It is usually from very high velocity and thus, hydraulic overload of the liquid filled body, that we get the bangflop/DRT type kills.
While I am not in any way diminishing a handguns ability to kill cleanly and make big holes, they cannot approach high velocity rifles in terms of damage to tissue, blood vessels and nervous system upset far from the impact zone that a rifle can impart. There are good reasons why 270's and 30/06's are used more often than 45/70's on deer and the like.
I have shot big game with exceedingly high velocity rounds like the 6/284 and 257WBY and caused bruising (burst blood vessels) across the entire ribcage and front shoulders of big game animals. Usually, in these cases, the lungs and upper heart are poured out of the thoracic cavity in liquified form. Travel after the hit from the animals is usually zero or maybe a couple of staggering steps, and that is all she wrote. A big hole from a big bore revolver would also have killed, if one was close enough to make a good hit, but not as dramatically or quickly and certainly not from as far away.
BUT, we cannot make a handgun bullet of sufficient weight go that fast out of a revolver or any managable semi auto handgun (I do not consider the XP-100's or long barreled Contenders etc to be true handguns, but more of a hybrid) to create those kinds of velocities so we have to rely on adequate penetration, sometimes with SOME expansion, and great bullet placement to do the job.
