Hi guys, it is not about caliber. Of course the size of the hole matters. What matters more is the first rule in any gunfight: have a gun! I have a Ruger Super Redhawk in 44Mag. Will surely make a mess of any attacker, but it resides in my safe, it is too big to carry. My Glock 19 sits on the hip, sleeps under my pillow. Which means I have a gun! I have experience of what a 9mm can do in the hands of a skilled person. Use what you are comfortable with, the rest is bull****. Any gun, more than an armslength away when the sh... hits he fan, is of no use, no matter the size the of the bullet. Wanna kill these ads? We can help!