Likely your magazines are back at Kahr now but when you get them back, load a few rounds into each one and strip them off like the slide would do using your thumb. The rounds should strip out like a greased pig then examine the cartridge cases for scratches. If you see scratches, the interior feed lips of the magazine has burrs. These can create enough drag to prevent your Kahr from chambering. I had burrs in my new P9 magazines causing failures to chamber. Take something like a wood dowel, toothbrush, etc. and push the magazine follower down, then lock it in place by putting a nail through the inspection holes. Take a hardened steel rod, like the shank of a drill bit, and burnish the interior magazine lips to rub off the burrs. This should eliminate any feed problems if this is caused by your magazines.