As a concealed carrier one of the concepts you need to be aware of is shot placement. Rather than debating on what caliber will do the most damage consider shot placement. Shot placement is king regardless of bullet size.
Timers – A timer is started as soon as a bullet impacts the human body. Depending on where the bullet impacts and the number of impacts will determine the speed of the timer. Once the timer expires so does the threat. So where on the human body will start the said timer? The most common is the high chest area (high A zone). By engaging the threat in the high chest area you are in effect hitting the lungs and possibly the heart. Another area to aim for to start a timer are shots to the abdomen and pelvic area.
Triggers – A trigger is a specific area on the human body, when impacted with a bullet, will dispatch the threat immediately. There are two primary areas on the human body that are considered a trigger. Those two areas are the head and the spine. In a recent course I attended, this is why the instructor focused on accuracy at 25 yards. We’ve seen active shooter events in the past where the shooter was wearing body armor. In this scenario you’re only option of immediately disabling the threat is a head shot.