I have an MK9 with about 1,000 rounds through it. It works perfectly, except...
There is a slight obstruction (easily overcome with a little extra force) during the pulling back of the slide at a point approximately 0.5" from full forward (i.e., from closed slide).
Obstruction disappears if trigger is held in pulled position when initiating the pulling back of the slide.
Obstruction continues to exist if slide stop pin is removed.
Obstruction continues to exist if barrel and recoil spring assembly is removed.
I can perceive that the obstruction disappears when the trigger is even touched as the slide hits the obstruction.
I suspect the cam is at fault, as that appears to be the only part that comes in contact with the slide that has any connection to the trigger position.
A visual inspection of all parts shows nothing bent, broken, worn, chipped, etc.
Anyone have any idea besides sending it back to Kahr?
I looked my MK9 over and think you may be on the right track. Having said that, IF you carry the gun, I would send it back to Kahr for repairs and testing.
My reasoning is liability. In these contentious days, anything you do to your carry gun should be done by the factory or factory authorized smiths and keep the invoices! I sent my blue steel K9 back to get nickel plated and some polishing done. I still have the invoice and that was over 10 years ago.