For what's worth
...
My BIL, LA Swat, 22yrs, Sgt now, 1 year to go, to retirement said that, in SWAT, they used nothing but 45cals.. period.
When he left SWAT for the rank increase of pay for retirement purposes, he was back on the street, and that LA's Police Policy was that all street cops had to use Glock (for their continued firing, after torture testing, including dropping the same Glock from an 8 story building, loaded, chambered, and no misfires, no damage other than a chip of the front sight and barrel, and scratches, but kept on firing without fail.
But the MAIN reason they went 9mm, was for damage control, in that, a 45 can go thru things, beyond its target, and do damage to other "things".. Where as, the 9mm JHP's did not go thru things and beyond, and therefore, was and is, the standard issue for the street cops.
Bottom line: one Caliber, the 45 is more forgiving IMO, than either the 40cal's or 9mm's more unforgiving, in a near perfect hit, vs the same shot-placement of a larger 45 caliber.
Puppet show:
The 45cal goes < boom------> O
The 40cal goes boom^ ------> 0
The 9mm goes bang^ -------> o
End of Puppet show..
Once he made Sgt., some 3yrs ago, he was, and is, allowed to carry his trusty, best handgun friend, a 1911, Government Issue, 45cal.
Some things make sense to others, but worrying about a street cops self protection, and his missed shots, or shots that go thru, or beyond, at the expense of knockdown power, vs the 9mm that, IMO, needs a better place- shotment, overall, to do the job, as compared to a more forgiving 45cal, with more punch on impact, and bigger holes, for the safety of the 9mm's less carrying power, flys in the face of logic, IMO, when it comes to street cops vs the concrete jungle of mis-fits that roam the streets and cities with their 45cals, semi's and auto's.
A 45cals heavier bullet, means more carrying power, as in inertia of weight, and can go thru doors, car doors, thru a corner wall, where the BG can be, far better, with less doubt, than both, the 40cal or 9mm. And that ends the BG's far faster, and for the better, than not.
To be fair, all calibers mentioned, are GOOD TO GO, with the right shot-placement by the shooter.
my 2 cents
LS
PS.. have you not seen, and heard, all the complaints of SUV's and their tank-driver ways? They do far more damage at 45mph, than any rice rocket coupe going 65mph.. why? Because of the SUV's weight, inertia, it does not slow down nearly as quick as a faster, but lighter, car, in an impact crash, to a complete stop.