I have shot the little Kahr MK9 several times, and I find it delightful to shoot...for about 50 rounds.
After 50 or so firings, the little gun seems to take a bite out of my thumb.
However, I would expect that in the event of using the MK9 for personal defense, one would consider the following:
* If you need to shoot more than 50 rounds in a personal defense situation, you are probably already dead and that little thumb bite isn't your biggest concern.
* If you escape any self defense situation with only a very minor flesh wound on your thumb, consider yourself very lucky.
Wm.