I would try the following: shoot another 200 rounds through the pistol, but when doing this, keep the slide "wet" with a good grade of gun oil (Hoppes). It is the slide that is your problem. It will wear in promptly if you shoot it wet, to carry off the microscopic flecks of metal.
WD-40 is NOT a gun oil, and has no place on any handgun. It is a "penetrant" not a lubricant. It was originally invented to spray on aircraft and equipment, parked outside in the weather, because the molecules are so small that they are smaller than water, and they get "underneath" the water and lift it off. (It also lifts off rust.)
WD-40 is so thin that it runs everyplace it shouldn't be, and then either evaporates or dries into a film.
As the Kahr company will tell you, in 98% of the cases that a pistol is returned for jamming, it is because the customer failed to propery break in the pistol as instructed in the manual. I had a friend that actually fired his Kahr "dry" for rthe first 200 rounds, and then couldn't understand why his pistol would keep jamming. I fired 80 rounds through it, keeping the slide wet, and it never jammed again.
Mannyrock