What can a 9mm do that a .38spl +P can't do just as well or better?
My thoughts exactly. I own autos and revolvers, but would 10x rather carry a revolver. But a 9mm revolver makes absolutely no sense to me. The 9mm vs. 38 Spec. ammo comparisons always compare light bullets and their higher velocity from the 9mm. What they DON'T show you is how a .38 Special shines with bullets from 150 gr. and up.
A few 38 Spec +P (20,000 psi)loads from Handloader #276 (fired from a Ruger LCR, no less):
140 gr. Speer JHP; 6.6 grs. Longshot-
932 fps
158 gr. RimRock SWCHP; 6.3 grs. Power Pistol-
1004 fps
173 gr. Cast SWC; 6.0 grs. Longshot-
913 fps
173 gr. Cast SWC; 7.0 grs. AA#5-
927 fps
173 gr. Cast SWC; 5.9 grs. Power Pistol-
946 fps
Additionally, if the LCR can withstand the pressures generated by the 9mm cartridge, then it can with stand similar pressure from a .38 Special, so loads even heavier than these would be possible, if desired.