Stopping power can be looked at in two ways from my point of view.
1. Stopping a threat, not caring if they live or die just stopping the threat.
2. Time to ceasation of brain function.
Personally, I could care less how long it takes for the brain to stop functioning. I want as much impact/trauma as possible. IMHO Hit the fastest, hardest, with the heaviest bullet that has the most expansion, without over-penetrating. And keep hitting them till the threat is over. Then remain prepared to do it again.
I want a devastating 4 inch diameter wound channel and a doubling in size of the round. 12-13" penetration.
Doubletap .40 155gr Gold Dot JHP @ 1275fps - 13.00" / .76"
Doubletap 10mm 155gr Gold Dot JHP @ 1475fps - 13.5" / .88"