>>4972428Actually there's a lot of factors that go into this, but the main factor is bullet design. Using older, non bonded hollow points, the jacket would frequently separate from the lead core, and essentially act as an FMJ at that point. In these scenarios .45 and .40 we're far more successful than 9mm. With the advancement in bullet technology recently, the differences have gotten much much slimmer. A .45, .40, and a 9mm PDX1 will all have similar penetration, expansion, and permanent wound cavity, regardless of caliber. (This applies to most bonded hollow points including the federal HST, and Hornady critical defense). With modern rounds, the only advantage bigger caliber rounds have over 9mm is energy transfer. But since handgun rounds don't provide the wounding effect of hydrostatic shock, like a rifle would, this extra energy transfer doesn't necessarily have fight stopping potential. In fact the reason most police departments use .40, is because they are stuck using federal hydroshock, or Winchester ranger non bonded rounds. When using old ammunition, you do notice a difference.
