The 45ACP was envisioned to give ~45 Colt performance out of an automatic pistol using a shortened case & (then) modern smokeless powder. "Penetration" notwithstanding, the 45 Colt using a heavy, relatively slow solid round-nose bullet was an absolutely-proven man-killer.
That was its job.
The 44 Magnum is an entirely different cartridge, for entirely different purposes, using an entirely different case, entirely different powders, designed to entirely different specs w/ an entirely different bullet series.
It's that apples & oranges comparison mentioned above.
At .44 -.45 diameter, bullet penetration is a function of bullet speed, mass, materials, frontal/flat step edge area, specific bullet expansion/fragmentation design, etc, etc. They ALL interact. More important, penetration is not nearly as critical factor as the bullet's ability to DUMP all its energy in the vital areas, smash bone, disrupt cardiovascular/CNS functions and not waste it by over-penetration into either non-vital areas or out into thin air (or worse -- innocents).
So the 45ACP (which will penetrate right through you w/ a 230gr FMJ) will also stop 12-15" in using hydroshok bullet designs driven at hydroshok velocities. The 44 Mag can be driven much faster, to penetrate much farther, and do much more damage on heavier/thicker-skinned animals than man.
But if I'm going into combat against men, I want the 45 Automatic Colt Pistol and its accompanying cartridge.
Guns are tools.
You pick the tool by the job.
Last edited by mehavey; August 1, 2011 at 08:47 AM.