Why don't you throw 454 Casull into the mix and make your statement more absurd. We are obviously discussing normal self defense calibers. I submit 5 rounds of .45 or .40 quality SD loads, placed center mass, will stop a BG faster than 9mm. To deny it is living in la la land. The point is pick a round that you can place well and quickly. A 9 used well is better than a 45 that you can't put on target. Simple as that!!.The average shooter can shoot more, and train more, with 9mm as opposed to .40. And the increased shootability of 9mm, for average shooters in particular, means that caliber is indeed an important issue if one intends to make hits. If caliber wasn't an issue, we'd all be carrying .44 magnums or something similar.