Like someone already said, if it's too big, you won't carry it all the time, right! I have carried a NAA22mag, questionably, lo end of power but probably better than a 32 auto., 25 auto, bad choice for self defence, 380 P3AT, a little better than a 22mag. maybe, PM9 Kahr 9mm, my smallest acceptable round, Kahr is small enough to carry comfortable waist band or pocket carry.
I have no desire to be shot with ANYTHING so I'm not saying any of the previously mentioned are not able to eliminate a problem, I just have a lower limit and all but the 9mm are what I consider to be lower limit carrys.
JMO
HM