I wonder how much of this is actually gun driven as well?
I seem to remember that Ayoob had some numbers a while back on revolver hit ratios with supposedly "trained" cops, and they were pretty dismal, something like 25%, which isnt good, especially when you only have 5 or 6 rounds on board. Those ratios jumped up when the cops started switching to autos. I realize the number of rounds fired also jumped up, but actual hits also seemed to be better.
Perhaps this more about perception, and has more to with the results of "misses" than it does with hits.
I dont think theres really a lot of difference between modern loads of the various realistic calibers, but shootabilty does make a big difference, especially if youre not willing to put in the effort to get good with what you carry. Unfortunately, many, if not most of the favored "carry" .38s, come in packages that require a good bit of constant work to be proficient with them, and are equally unfortunate to be brutal to shoot enough to achieve that.