CM40 Feed ramp vs. follower

[bigdave622]

Got my CM 40 a few weeks back. Went to the range and shot 110 rounds. 100 Independence FMJ, 5 Buffalo Bore and 5 Liberty. Broke 2 followers. Received 2 followers from Kahr. Next visit to the range while rotating 4 mags, 2 followers broken in 100 rounds. Contacted Kahr again they said they would send a RMA if I liked. I told them no just send the followers.
I work in machine shop and have been around precision mechanical assemblies for 35 years so surely this smells like an interference problem.
Locking the slide back and putting a small strip of paper down the feed ramp I put in an empty mag. I could not remove the paper shim without resistance. Ah Ha !! Feed ramp is slamming the follower after last round ( the only time the follower is exposed ). This may not be for everyone but a stoned the bottom of the feed ramp with a Dremel, then some 600 paper then polished only that spot where I ground with a felt wheel and some jewelers rouge. Took Prussian blue and applied to the feed ramp and put in a empty mag. Still had a little interference so I repeated the process until no Prussian blue transferred onto the follower. Put 100 rounds through today without a hiccup using the same mag all the way and NO BROKEN FOLLOWER. Problem goes away.
Now I'll add some Talon grips and my summer EDC is ready !!!!

[Bawanna]

Well done.

[jocko]

that is exactly what kahr would have done, so u knowledge and skills saved alot of time on ur part. U did a nice job. they do have a clearance issue on some of their kahrs, I think they are gettingtote bottom of this issue to, for we see far less than 6 months ago.. I had seemed even more prevelant in the kahr 40's thab most utter models. I attribute that to the violent explosion of the 40 cal round in the gun and it seems things just get a tad out of whack beyond design. Just my 21 cents on this..

again nice work, welcome tothe forum. sounds like u might be able to enhance our forum even... where u moded the feed ramp a round never gets that low in the first place..:Amflag2:

[b4uqzme]

well done! so bigdave, I hear you are volunteering to be the forum gunsmith...

Welcome :yo:

[bigdave622]

Thanks for all the compliments. Maybe I save some others a headache.
B4uqzme, I'll answer an questions if I can, but if I'm gonna start smithing I 've got to make a few bucks :)
Jocko, That's also one of the things I checked. When you see where the round actually meets the ramp it's not so hard to grind down the high spot

[bigdave622]

105 rounds through today. 100 FMJ and 5 Gold Dots. This gun eats anything. Really smoothing out. Trigger, slide, springs all wearing in nicely.
First and foremost, NO BROKEN FOLLOWERS !! My ramp job working perfectly. Finally getting used to the trigger. A lot more hits up in the zone today even at 30 ft.
Liking this gun more each time out.
400+ rounds through this gun

[340pd]

Pics?

[plateshooter]

bigdave, were your followers breaking off the front guide leg? I tried a new 9mm 7 round mag and the front leg of the follower broke off.

Thanks

[jocko]

that usually where they break off, the feed ramp is hitting it... I would try one more new follower and if it breaks, then get ahold of kahr attn: Jay and ask them to pick it up. I have over 32K rounds out of my PMJ9 and have had one broken follower. Had it continued I would have sent it back but it stopped so enough of the gun has changed from break-in or what ever to now not be an issue..

[Linthead]

Not a new problem and one that Kahr has known about for a long time. I have to wonder why Kahr is allowing it to continue.

[bigdave622]

plateshooter, yes the guide leg. Steel vs. plastic... steel wins everytime

[plateshooter]

I did the bigdave fix. Seems to work fine with the one good follower I have left from my 3 mags. Question is, does that front leg have much to do with feed and function. Mags with the broken off front legs seem to feed and function fine. I would not have known they were broken except for the piece I found when cleaning the gun. I still have not had one problem with reliability even with the broken legs. BTW I'm shooting a 9mm.

[jocko]

good question. Ihade the front portion of my follower break and I didn't know it and thegun was flawless. BUT it an't suppose dto do that, so keep an eye on that area..

[CJB]

Pictures !!!!! Please

[plateshooter]

good question. Ihade the front portion of my follower break and I didn't know it and thegun was flawless. BUT it an't suppose dto do that, so keep an eye on that area..

Will do Jocko. After doing the bigdave fix, I have no contact with the feed ramp and the follower any longer. I could feel quite a bit before the modification by setting the barrel on the frame, installing the slide stop then seating an empty mag (with an unbroken follower) . It would tip the barrel forward. Not so now. I didn't have the blue print die but I had a blue sharpie to check for contact. At least they are both blue:).

The gun feeds fine even slow racking it by hand. Kahr was going to send me a call tag, but I REALLY hate sending guns out for repair. I called Kahr back and told them just replace the followers and I would be good to go.

I think it will run perfectly and no longer be a follower breaker. If anything does not work, I'll post it here.

I will try to get a pic of the modified feed ramp. I can't do a before pic because that is in the past and I live in the present moment :D

[TheTman]

Thanks for posting your fix.

[bigdave622]

plateshooter, glad it worked out for you. The mag will still function with the piece broken off but the follower has trouble piloting into the mag until the first two or three rounds are loaded. I had no problem feeding with the busted ones but didn't feel comfortable carrying like that. I also put the barrel in the frame and put the slide stop in without the slide. You can see a little better in there. Holding the barrel to the frame while inserting an empty mag lets you see and feel the interference. I'll try to get some pictures up this weekend.

[plateshooter]

Really appreciate the tips bigdave. I really enjoy working on guns and it is nice when it works out.

[oncechance]

Yes, please post some pics.