40grs at 2200 fps should provide adequate stopping power, Hell, a pocket 9mm can offer that more power than that,rather easily. It'sjust a matter of making a THV-Arcane shaped bullet, out of pure tin, and rechambering the barrel to 356TSW. 45 grs, 2200fps. Jeff was talking about a .22 sptizer BALL bullet, AFTER penetrating soft body armor, too.
Since the 9mm has 2x the "frontal area" of the .22, it's obvious that either Jeff is fos about this, or the 9mm pocket gun has plenty of power. 