A round from a.45 on body armor is going to hit the person wearing the body armor with the force of a lead pipe or a tree trunk. If you're a decent shot armed with a .45, the guy wearing body armor will be on his ass, head shot or not.
Gotta love them 45’s. Not sure if the LEOs there carry that. Maybe .40 but I’m thinking 9mm. And of course that ever popular (with criminals that is) AR variant in that exceedingly high powered .223. Kind of doubt that bad guy can run at 3000+/- fps.
“If you’re a decent shot armed with a .45, the guy wearing body armor will be on his ass, head shot or not.”
If you were correct, the SHOOTER would also land on his rump. The bullet doesn’t have more energy at impact than it had leaving the gun.