My problem is I bought a P40 for a backup gun (I am a LEO) and I carry it inside my outside vest carrier If I dont take it apart and oil it everyday when I shoot it the slide wont fully close and I have to tap it after every round, I know it gets some moisture due to being close to the body all day long in the vest(but I have a tshirt and uniform shirt between my body and gun) but the glock I used to use never had this problem. I have about 600 rounds through it and LOVE the gun but CAN NOT trust my life to it, I also have several guys on the dept. who would like a KAHR but have seen my FTF and got turned off by it. Any suggestions I am going to contact KAHR about this but untill it gets fixed any ideals.

I LOVE my P40, right now more than my H&K USP40. I don't know if you have read the "Slide locking back" thread yet, but that may be worth looking into. Perhaps the "bearing fit" is too tight, and not allowing your barrel to move into full battery and then holding up the slide. Mine has NEVER not worked. If all else fails, call Kahr, let them know why you want to carry their pistol, then see what happens.

I would try a new load. My Kahr P-9 hated 124 +P Gold Dot hollow points for a while but later ate right through them but until they worked well I shot other types of ammo. 600 rounds does'nt seem like a whole lot of ammo comparitively. If it were to go 300 rounds no problem than good to go if not I would'nt carry it.
You may want to change the lubricant you use. Sounds like it is running out or drying up. I like Tetra lub and grease. I put a small line on each rail polish it in with a q-tip. I do the same on all metal on metal spots. I leave only a thin film on the metal it I see white I take it off. then I follow up with a small drop of terta's oil on the parts I greased. whipe off excess and assemble as normal. I no long had those annoying spots from the oil on my clothes and it does'nt dry up or become gummy from lint or dust... Hey I am human I sometimes get lazy and go a couple of weeks with out cleaning it... (head hung in shame) LOL
Seriously it may just be a break in time frame and time to try a new lube. Hope this may help.

I had the same problem.  I took it back to where i bought it and the gun shop owner went to the range with me.  He fired it flawlessly.  He advised me to clean and lube it every time I fired it, showed me how to avoid limp wristing and recommended a bullet less than 180 gr.  It works flawlessly when clean now.  I'm intending to get the Agrip to prevent my thumb from pressing the mag release while I fire it.  Good luck.

I agree with MPA249 & sigarkar. It sounds like a lubrication issue to me. I used to use Break Free on my MK9 backup. I carried it in an ankle holster, so it stayed wet most every day during the warm months (about 7 months a year). The rest of the time, when I wore boots with my uniform, the gun was in a holster on the vest straps. I had a problem with keeping the gun lubed too, & since stainless has a tendency to gall unless well lubed, I pretty much had to clean it (or at least wipe it down) every day I carried it. I switched over to FP10 lubricant & had a lot fewer problems with the gun getting dry on the rails & slide.

I have since switched to a PM9 for my backup, & have had no problems with failures to go into battery after the break-in period.

Try a new recoil spring. The gun should run dirty, clean, lubed or not. If the spring doesn't fix it, send it to Kahr.