I only need enough rounds to scare them away or get away myself. I don't plan on Ana extended gun battle
An "extended gun battle" is usually about 15-20 seconds. It does not take long to burn through a mag in a semi-auto if you're fighting for your life. My take is that if you carry... especially a lower capacity pistol, spends lots of money on ammo and training, especially stress-induced training. It will save your life.