I have two Kel-tec P32s and a P11 that work fine. I have a P40 that, in spite of trying a wide variety of ammo, replacing the slide and barrel with hard chromed ones, polishing the feed ramp, and always using a firm two-handed hold, has never been reliable. Maybe I'm limp wristing, but if they are this touchy, there's something wrong. I like Kel-tec, and Cliff, the gunsmith there, has offered to replace my frame with a new one (destroying my old one and putting my original serial number on the replacement) under warranty. I'm not sure if this will make a difference or not, but I hope so. I offered to just swap the .40 S&W barrel for a .357 Sig (which Cliff confirmed feeds more reliably in these pistols), but he said he can't do that. If the new frame doesn't help, I'll probably just buy a .357 Sig barrel and give it a try. I really like Kel-tec pistols, and the company, but I think there is more than "user error" involved in the decision to stop making the P40. If the same grip that works fine with every other handgun I own (and that's a fair number) won't work with the P40, I don't think it can really be called user error. By the way, I'm 6'2", 235lbs, not especially weak, and have been shooting handguns for almost 30 years. I don't find the recoil of the P40 particularly uncomfortable (compared to light .357s, etc.) - I just wish I could have confidence in it.
Doug