I like 9 mm also, and I think his Kahr is a dandy little gun. But I certainly don't see any meaningful difference, alone a "big difference".
As for your 640, I think . 38 +P is the way to go in a snub. Just too much loss in velocity in .357 and then you add the flash, noise, and horrendous recoil.

Last edited by KevinGibson; 09/07/13.