"The .40 s&w was engineered by smith adn wesson and federal, it was made to stop a human with 1 well palced shot."
Actually, no.
When once upon a time there was only the 9mm vs the .45acp, 1911-guru and gunfight expert Jeff Cooper engineered the
10mm AUTO (okay, he had
some help) for the express purpose of stopping an aggressive 2-legged predator with one well-placed shot C.O.M. Cooper envisioned the 10mm as a
combat cartridge for a large-frame (.45-size) autoloader - whether that "combat" occurred on a battlefield or in an urban back alley.
The .40S&W, on the other hand, was a derivative cartridge created from the 10mm for two primary reasons, neither of which has anything to do with one-shot stops on humans:
* The first reason involves individual convenience: the .40's shorter overall size allowed it to be loaded into
9mm-size autos (smaller and lighter to carry
). Small-frame guns fit the hands of the females and the small-statured men (i.e., typically non-shooter types) so enthusiastically being recruited into the ranks of American law enforcement since the early 1980s.
* The second reason involves organizational convenience and protection: the .40's down-loaded ballistics (e.g., 180gns @ 950fps) more easily allow said nonshooters to pass their annual or semi-annual firearms qualifications, thus protecting their LE agency or department from liability ("it must be great training, everybody passed") and from having to increase the ammo budget and range time for training and re-quals by those failing the first time around, as was the case when a 10mm or .45acp was issued.
In reality, increasing the probability of a one-shot stop, even if such a thing quantifiably existed, was not the reason the .40S&W came into being.