Who says that the firing will be at 6m? 6 FEET is more like reality. Who says that you will even get off more than one shot, much less get to empty the mag, then grap an ANKLE gun. A man can easily be all OVER you from 6m in 2 seconds, a truly fast man can do so in 1.5 secs, and even a fat guy can be so in 1.5 seconds if he starts at 10ft distant. Who says that the fight won't start at the length or width of a car? In fact, it USUALLY does. Have you ever TIMED getting hits on the head, at 3-6 ft, even on a STATIONARY target? I guarantee that you won't get more than .35 sec splits with plus p 158's in a steel 38 snub, and not better than .50 sec with the air wts. Most headshots are deflected by the skull, but ADEQUATELY powerful hits to the head at least dazzle the guy, anyway, allowing you to hit him again. Firing only once at the head is childlike in its fantasy about success on such a small, moving mark. The knee is an even smaller mark,much more mobile, much less likely to suffice, and it calls for too great (read too SLOW) shift of POA. When your adrenalin dumps, you will be LUCKY to hit the chest with all shots, at a mere 10ft, that is REALITY. Knee shots are asinine claims by the ignorant. You can't even justify such in court. Firing at someone is lethal force. If you are not in fear of your life, why are you aiming at the knee? A lawyer will tear you apart in court. The jury is made up of little old ladies, remember. You will rarely have more than 2 seconds in which to have more than LUCK determine the outcome. If you must make a concealed draw, from a belt rig, 1-2 shots, at 6 ft and less, is probably all that you will get to fire. That's why you want a TRULY powerful, yet controlable gun. Such can be had, even in a pocket auto. You just have to use the really hi-v prefrags, in the 357 Sig or 356 TSW, in the Keltec or the Kahr. 600+ ftlbs. In belt guns, you can have 900 ftlbs, 2400 fps, like a 223 softpoint, by using such ammo.