For CCW and/or SD the new Hornady Critical defense 22 WMR seems to have a ot of promise. I found some at LGS and bought all they had 18 boxes. Then I started testing them in my various revolvers (and my Winchester 61 pump).
IN the little North American Arms you know you have fired something, but in slightly heavier guns, M650, M651, M651C they put out some substantial ooomph. Iwould have no problem depending on that round for defense. It penetrates several inches into 2X4" wood and expands reliably from snub barrels. I have no doubt that someone peforated by a couple of these rounds would lose interest in being a BG really rapidly. I looked through one of my holster drawers and found a long forgotten belt pouch that holds 12 WMRs in single holes in the drop section of the pouch. Starting to think that the 650 (3") or the 651C might be a nice combo field SD revolver.