Well.... I see disinformation, and such. Not picking on anybody here, but I'll list a few things I see here in the thread.
1. They have really tight tolerances.
Actually not really. That is a bit of self promoted (by Kahr) double speak. The "tight tolerance" thing is one way of getting around "some break in may be required". Here's the skinny on that. The Kahrs are a very specialized pistol. Their reason for being is "small". The K9, P9, PM9 all have what may be termed a short dwell time after that breach face clears the back of the cartridge in the magazine. You look at a 1911, many other auto-loaders, and the slide has lots of overtravel. That, coupled with a heavier slide (because its bigger), and a slower moving slide (because its heavier) makes for a longer time period for the cartridge to rise. Couple that with the following concept...."We don't make the springs to be the tension they need to be. We make them tighter, knowing they'll become the tension they need to be, with shooting". That is a must do in manufacturing of the Kahr design due to the tricky slide velocity and short dwell time. Kahr has no control over the ammo used. So, they suggest a break in (not a bad thing with any autoloader). SPRINGS do not take much of a "set" while under constant tension. They take much more of a "set" under dynamic conditions (flexing). So locking back the slide has little to help. Shooting has all the help you'll need, and can use when breaking in the spring. BTW, when you change the recoil spring, its break in time again... just sayin'.
2. My PM9 absolutely will not feed the first round from the magazine if I slingshot the slide.
Which is why Kahr says not to do so. Some will, some wont. Its a combination of very strong spring making holding back the slide difficult, and getting enough "snap" on release. Using the slide stop works reliably and the factory says do it that way.
3. Justin Moon was the chief designer at Kahr, and still is for all I know. He designed the PM9 when he was a junior in college..
Justin designed the K9 in college (sort of) not the PM9, but... that's nit picking. He's a class act though, and has stood behind his product when they had a few manufacturing issues (flaking nickel finish, bad ramps on 40 cal, etc)
The PM and CM series are identical in frames, all the same parts, everything 100 percent the same. The difference is in the "machining" of the slide (big woop), the lettering (big woop) the sights (maybe an issue for some), the slide stop (no issue as I'll explain), and barrel.
Barrel first. Kahr says those accurate polygonal rifling barrels are so expensive to make. Hogwash. The mandrel on the hammer forging can be poly or conventional rifling, they come out of the hammer forging machine in the same amount of time. "We start out with a 3 inch bar of steel". True dat. Three inches diameter before hammer forging, which makes 'em long and skinny, ready to be made into pistol barrels. Doesn't matter the rifling. That's all sales department hyperbole.
Slide stop... The PM has a "machined" (not cast, not "forged") slide stop. Not quite. Get out Mr. Magnifier and look at the PM slide stop. Its made with a ground very hard pin, that can rotate in the paddle section of the stop. It has a groove and the paddle is held by a cross pin. The paddle section is MIM. Yup. The entire slide stop of the CM is MIM, pin and all. Oh no, cheap crap MIM parts... oh the agony. Forget it. MIM is great. Colt has used MIM slide stops, thumb safeties, disconnectors, for DECADES, you never really hear of an issue.
Sights on the PM are dovetail in front, while the CM are plastic fit into round holes.
As far as the "expensive" machining on the PM series... er... the cost is the time in their FADAL CNC machining station. Cost is measured in time of production. Time of production "may" be more for the PM slide, but insignificantly so. Same for the lettering. More hyperbole by sales department.
Here's the thing - the PM and CM are the same cost of production. Very small differences. Kahr needed to introduce parts and features that were perceived as "cheap" to have a lower end model, regardless of cost of production. Put another way, they made money on the CM, and make a killing on the PM because its perceived as being better, even though cost of production is almost the same. Slick trick. Yay sales department.
With that all said, I've owned 5 PM series Kahrs, still have two (one was stolen, the ex got two in the split). They work. Period. Never an issue, except, on a brand new recoil spring, or new gun, I've gotten some hangups for the first few magazines full, where I had to whack the back of the slide to chamber the round. After that.... no issues at all. They all did it for me, but... that was WWB ammo, and my hand/wrist holding the gun. YMMV.
Trigger needs getting used to, but... I like the long pull. Safer in the pocket. And that is why I carry DAO revolvers (Charter Boomer) or Kahr for EDC in my pocket. I trust 'em because I know their reliability.