1. I wouldn't carry ball/fmj in anything larger than .380 Doing so reallly takes a risk on over penetration and making it more dangerous for others that the bullet wasn't intended for.
2. To the OP. In all honesty, i do not shoot well enough for the different weight bullets to shoot any different than each other. At 25yrds and under its all the same for me with what i have tried.
As to point one, I can't argue the case against over penetration. At the same time, I fly in the face of most pundits and welcome the possibility.
How many studies have been done supporting penetration as primary factor in a bullets effectiveness?
I go with that. Here I'm referring to recorded shootings and what would be considered military effectiveness.
It also helps that the standard loading, 230gr RN @800 fps, remains one of the most effective handgun rounds in existence. It's relatively inexpensive, too. It's that "total package" I'm liking.
I don't carry the XD in public, so it's not something I worry about in that regard. It is in rotation as house gun, however. But it's just me and my wife - I know where she is in the event it's needed. Should a bullet go through a few walls (hopefully after perforating an offender), well....I know how to patch drywall.
I don't care about a bullet exiting to the exterior, either, as I live rather far out in the country.
I do carry around the property, though, and tolerate the possibility of over penetration there. In short, I don't have much to hit should my shot miss or puncture through.
But you've given food for thought. There may be new data the suggests more effective rounds exist. I haven't checked in a few years. But for over a century the standard round has done the job. I can go with that.
2. Very good point as to accuracy. Within the boundaries of a residence, or a self defense application, intrinsic accuracy is my least concern.
If I'm shooting farther than 30 yards, well... should be getting to cover and reviewing my tactics.