Hornaday HST until I finally run out, then probably gold dot.
The load that *most* satisfies my criteria is the simple 148 gr. full wadcutter, ideally Winchester X38SMRP due to its relatively high velocity for a target load. Even at its modest target ammo velocity you can expect 14" to 17" of penetration (mostly 15" to 17") and the sharp shoulder tends to punch holes rather than worm its way around organs like round-nosed projectiles (such as hollowpoints that don't expand).
Alk8944It makes absolutely no difference if your 2" nominal length barrel revolver is a J-Frame or K-Frame, so forget that qualifier.
For starters, I've been carrying a M649 stoked with Mag-Tech 158 grain FMJ-Flat cartridges for some time now. Why? I can't remember but I think they were left over from a range session so I retained them for carry. To avoid over penetration in the unlikely event of a confrontation I'm thinking of going back to Hornady Critical Defense ammunition.
Speer Gold Dot 135 gr Short Barrel. Good enough for NYPD, good enough for me.