What is the best ammo for stopping power
There isn't any,
Quickest way to turn me off is tell my your Band X is will stop anything in its tracks.
Go hunting, or watch some hunting shows on the Outdoor or Sportsman's Channel.
Very seldom is an animal shot and hit in the vital heart lung are and it goes down. It most always runs off a short ways, or a long ways.
And that's with a high power rifle on a 100-125 lb deer.
So how can we expect a 200 lb man to go down instantly after being shot with a pistol or revolver.
In my LE CSI days I've seen a lot of gun shot victoms and I've been to a lot of autopies. One thing I learned is you never can tell what a bullet, any bullet, large or small is going to do until it does it.
I don't recommend any calibers but I tell my students of my firearm safety and self defense classes that A little gun you can shoot beats a big gun you can't shoot every time.