I don't think there is much different in "stopping" vs "killing".

If the bullets don't hit the spine or brain, the BG doesn't have to stop immediate aggression unless they choose too. Doesn't matter whether it's 5 hits from a .25 or .45.

-I do agree that light bullets are more likely to veer off the intended path inside tissue
-Bullets that penetrate more are more likely to strike the brain or spine should they be on that path
-Bullets that penetrate more are more likely to penetrate cover for BG's and bystanders/folks downrange

I decided against the Cheetah .380 because I think it's barely any improvement over my beloved Cheetah .32.