Why is the 9mm too small? In world war 2, they could not find the hearts of men hit in that area with 9mm fire. Both the 9mm and .45ACP do not "over-penetrate". Will a .45 penetrate modern kevlar body armor, because the North Hollywood Bank Shootout showed us that the cop issue 9mm wouldn't, but day to day, law enforcement seems to prefer 9mm. 9mm goes in but does it come out? I would not want to be shot with anything so I won't say what I've heard alot of in my neck of the woods "9mm is a peeshooter and will bounce right off flesh". So to those people, ever been shot with one? Please lets all opinions on this, .45: one shot down, 9mm: one shot down, maybe gets back up, but higher capacity to put more down. let me know.