I have seen LOTS of dead gang bangers in Little Rock with no visible wounds, later found to be shot with .22.
You are right though, limited stop potential UNLESS YOU CAN score with a head shot.
Even then, the head is basically round, with some flat on the sides. Unless you can hit it pretty square on, .22 is likely to cause a bloody wound and big headache, but not a quick stop. Of course that's physically, The whack in the head and lots of blood would result in a psychological stop in most cases, but not all, especially if the shootee is drunk or high, a likely condition during a riot.