Had my first malfunction with my CM9 last weekend.  About 1500 rounds through it, total.  My backup gun, so not shot all the time, but I try to practice with it often enough, since I'm mostly used to the Glock trigger.  I have only three mags for it, two 6rd and one 7rd.  Anyway, shooting it a couple of days ago and it FTFs on me.  Live round won't go into the chamber all the way.  Tap, rack and same thing.  Isolate the problem to one mag, a 6rd.  Then take my ears off and I hear it rattling.  Take the mag apart and see that the front leg of the follower is snapped off, floating inside the mag body, and there's another crack forming from the metal pin that engages the slide stop.  

Is this a common part to break?  Will Kahr hook it up if I email them?

Sort of common, although I never had it happen to me, probably due to not shooting enough. Kahr should make it right. I've read of other people getting free mag followers but I think I remember something about Kahr modifying feed ramps or something to keep the recoil lug from hitting the follower.

Happened to one of my CM9's and my CW9, i shoot them often so i guess that sped up the process, Kahr replaced both followers free but said if it happened again the would want the whole gun.

For a rampectomy.
They did my PM9 in 2013 after it broke a total of three followers. They also sent me a couple of extras prior to the rampectomy.

Happened on my PM40.

I  came here to ask about their mag followers.  Just pulled a spare mag out of my pocket to show a coworker how much lint gets into things and decided to take it apart.  Front leg of the follower falls off.  Did see some cnc'd metal replacement ones on the net. Lakeline.   Ordered replacements for all my mags and one +1 extension.

Thats how my CW9 follower broke, took it apart to clean it out, front leg popped off after i shucked the last round.

The lakeline followers are nice but 2/3s the cost of a new mag.  Their plus one extension is very nice and low profile, but $30 and won't work with their follower in a 6 round mag which seems ridiculous. So I had to use one of the plastic followers with that mag and now I have one spare plastic follower and one spare lakeline.   Fired a couple hundred rounds through them last week and everything worked as it should, I don't remember any issues.

In all likelihood if you're getting broken followers the barrel ramp is contacting the follower when firing the gun. Enough shooting and it will continue to break, all that is needed is to remove a little off the front of the ramp. Had this same issue with my CM9.

My used PM9 came with those followers. They work wonderful
ETA, in the 6rd and 7 rd mags

http://www.ar15.com/forums/topic.html?b=5&f=35&t=143232

modify feed ramp