The limp-wrist idea crossed my mind on reading the OP, too.
But the biggest point to emphasize is that neither one has been sufficiently reliable in your hands. If you can get some coaching, training, and practice in that makes one of them reliable, or if the Kahr is really and truly fixed this time, fine. Otherwise it might be time to cut your losses, as disappointing as that may sound.
ETA: Please note that 50 rounds in the hands of someone else does not prove the pistol. The pistol needs to work well in your hands, and for a hundred or two hundred rounds overall, and a significant number of your defensive rounds (say 50 or more) to regain some level of your trust.