1st off, I'm not a gun nut...imma a S gun nut ( Saigas and Sigs). Partial right now to a Sig P228 but in the process of migrating to a SigPro 2022 in 9 mm, which would be my rec.
I ran across this info that might help you in caliber choice.
http://ammo.ar15.com/project/Self_Defense_Ammo_FAQ/index.htm
lctrav