Here is a great comparison that you really should take some time to go read… over at Pocket Guns And Gear. What Bruce has done is to compare both the 9mm Federal Premium HP with the 380 Federal Premium HP out of what is essentially the same concealed carry gun(s).
Why is this important? Because our ‘golden age’ of carry guns is now really even more so ‘more golden-er’. Mouse Guns (pocket guns) have been around for some time, but now is the time in history when they are readily available from several different manufacturers in non-mouse gun calibers. Now-a-days we really dont have to make a trade off in caliber for pocket sized concealability. What Bruce has put together is a great look at what the trade off is really all about.
*I will also note, that you should pay close attention to the bone-block testing he has done. As I have noted in the past, we human beings are not made up of just ballistic gelatin. Dont Get Boned!
… More here.