I bought my K40 second hand but it was new and never fired. I cleaned the assembly lube out, including the striker channel and lubed it, but kept the striker channel dry. I also had to clean sticky stuff off the magazines. Function checked it and it dry fires every time. I took it to the range and only shot 35 rounds through it because I mostly brought 300 Blackout ammo to shoot. After the first magazine it started failing to reset the trigger every other round or so from both magazines, so I would pull the slide back a little to reset it and then fired. Extraction, ejection and feeding was flawless. I brought it home, cleaned it including the striker channel, but this time took out the cam and ejector and cleaned and lubed them also. I also cleaned where the trigger bar slides and made sure no gunk was in there or in the notch in the slide. It still resets when I dry fire so seems to work. I just got 100 rounds of Winchester White Box in the mail and will give you an update next week.

I have researched on this forum a ton and everytime someone has this problem and sent it into Kahr, Kahr either reworks or replaces the trigger bar. My trigger bar is making good contact with the cam and is not touching the magazine.

I called Kahr about a month ago to see when it was manufactured because the test casings weren't included and they said 4/11/2014 so I doubt they will honor the 5-year warranty since it probably expired last year. But at least you can buy new parts from their website. I will take it to the range and see if it works itself out, if not I will buy a new trigger bar (around $20 shipped).