The term "stopping power" confuses a lot of people...
It leads to the more power/better performance mindset...which is dangerous.
There is some truth to "bigger is better" but it is towards the bottom of the list of importance
People stop either because they;
1. Lose the will to fight (psychological)
2. They lose enough blood that they can't function
3. They get hit in the CNS (turn out the lights)
Less effective rounds can kill instantly but they pretty much require #1 or #3
Effective rounds disrupt tissue....they penetrate far enough to hit major organs and they leave a nasty hole so blood will run out.
Think bigger deeper holes (aka bigger is better...maybe)
Bullet design is more important than caliber with one caveat....most all bullet designs need a minimum amount of velocity in order to penetrate AND expand....below 9mm/.38 that is almost impossible.
Most bullet designs have a velocity range in which they exhibit the required amount of penetration AND expansion....so your best choice may be predicated on barrel length to some extent.
The two most important things to remember
1. Shot placement(for multiple shots) is key
2. Gun magazines are not the best place to get terminal effectiveness data
So...in a nutshell...the best .9mm loadings are pretty much on par with the best .45 loadings...
So if you can get multiple accurate hits with a .45...by all means...use tha larger round.
But...if a smaller caliber (no lower than 9mm) allows you to make faster, more consistent hits...then you may be better served with a 9mm
It leads to the more power/better performance mindset...which is dangerous.
There is some truth to "bigger is better" but it is towards the bottom of the list of importance
People stop either because they;
1. Lose the will to fight (psychological)
2. They lose enough blood that they can't function
3. They get hit in the CNS (turn out the lights)
Less effective rounds can kill instantly but they pretty much require #1 or #3
Effective rounds disrupt tissue....they penetrate far enough to hit major organs and they leave a nasty hole so blood will run out.
Think bigger deeper holes (aka bigger is better...maybe)
Bullet design is more important than caliber with one caveat....most all bullet designs need a minimum amount of velocity in order to penetrate AND expand....below 9mm/.38 that is almost impossible.
Most bullet designs have a velocity range in which they exhibit the required amount of penetration AND expansion....so your best choice may be predicated on barrel length to some extent.
The two most important things to remember
1. Shot placement(for multiple shots) is key
2. Gun magazines are not the best place to get terminal effectiveness data
So...in a nutshell...the best .9mm loadings are pretty much on par with the best .45 loadings...
So if you can get multiple accurate hits with a .45...by all means...use tha larger round.
But...if a smaller caliber (no lower than 9mm) allows you to make faster, more consistent hits...then you may be better served with a 9mm