Bit of a problem with a CW40

[NWShooter]

I've got a CW40 that I bought on January 12, 2013. I field stripped it late last year and reassembled in accordance with the manual. The slide would not go back to battery until I pushed in a touch on the slide release. As in, pushed it towards the frame of the pistol. I contacted Kahr and they sent me a new slide stop spring, item 29 on the parts list. No help and I put the original spring back in. Now the slide goes to battery without a problem. Unfortunately, it will not lock to the rear, either on an empty magazine or with no magazine present and manually trying to move the slide stop up to lock it. The slide stop will not move up when the slide is held to the rear.

I have several hundred rounds through this pistol and it has worked flawlessly on the range. However, this problem when field stripping and cleaning it is troubling. Until it is resolved I am reluctant to take this pistol to the range and shoot it again. Not the end of the world, I have a number of other guns in the safe to choose from. And, yes, I have been shooting for a number of decades and know how to field strip and reassemble a pistol, especially when the instructions are right under my nose. :-)

Suggestions? I know I can send it back to Kahr, but if it's something simple I don't have a problem with fixing it myself.

Thanks.

[gb6491]

I've got a CW40 that I bought on January 12, 2013. I field stripped it late last year and reassembled in accordance with the manual. The slide would not go back to battery until I pushed in a touch on the slide release. As in, pushed it towards the frame of the pistol. I contacted Kahr and they sent me a new slide stop spring, item 29 on the parts list. No help and I put the original spring back in. Now the slide goes to battery without a problem. Unfortunately, it will not lock to the rear, either on an empty magazine or with no magazine present and manually trying to move the slide stop up to lock it. The slide stop will not move up when the slide is held to the rear.

I have several hundred rounds through this pistol and it has worked flawlessly on the range. However, this problem when field stripping and cleaning it is troubling. Until it is resolved I am reluctant to take this pistol to the range and shoot it again. Not the end of the world, I have a number of other guns in the safe to choose from. And, yes, I have been shooting for a number of decades and know how to field strip and reassemble a pistol, especially when the instructions are right under my nose. :-)

Suggestions? I know I can send it back to Kahr, but if it's something simple I don't have a problem with fixing it myself.

Thanks.

Let's look at this first.
Is the slide moving far enough to the rear?
This is the minimum distance rearward that I can lock my CW9's slide back:


This is as far back as the slide on my CW9 will go:


If your CW40's slide is not moving back enough, my first thought would be to check that the recoil spring is installed correctly and see how many coils the spring has.
Here's my CW9's recoil spring correctly installed on the guide rod. It has 20 coils:


The following may not be applicable in your case, but I thought it worth mentioning. If the leg of the slide stop spring is not on top of the lever when the slide stop is installed, the lever will always be up making it seem that the lever has no travel. Here's where the spring's leg seats:



I'm at the max number of photos allowed per post, so I'll continue in another post, but let me say here: Welcome to the forums!

Regards,
Greg

[gb6491]

If the stuff I mentioned in my earlier post checked out, I would start looking at components that might prevent the slide stop from moving up.
First, I'd look that the stop installs correctly in the frame and has clearance to travel freely up and down.

Here's the clearance of my CW9's stop with the slide installed:

If that checks good, I'd look at the stop, checking for anything that might prevent it from traveling up enough to lock the slide back. Perhaps a burr/deformity along this edge:

Lastly, I'd check the the slide is machined correctly. Too large a width here might cause problems (likewise, too narrow a gap on the stop, from that arrow in the photo above to the inside of the lever):

Anyway, those are my guesses. If they don't help perhaps you could post some photos or additional info.
Regards,
Greg

[Bobshouse]

Greg, you are really one of the greatest. Others try to help with links (mostly to your posts), and advice, but you are the only one I know that goes to such great lengths to help a stranger. Thanks for all the great help, outstanding photos and detailed information you provide!

[NWShooter]

Greg,

I really appreciate the time you've taken with this and the pictures you've shared. I've taken them to the bench and compared them with my pistol. I don't see any discrepancies so far. Let me provide a little more information, based on today's experimentation...

With the pistol field stripped if I put the slide stop back in without the slide in place I can move it "up and down" as if I were locking the slide until I firmly finish putting it in place in the frame. Once it is in all the way it will not move "up and down" as if I were trying to lock the slide to the rear. It moves freely when not all the way in and as I move it towards the fully in position there is a little opposition to moving it up and down until the final "click", at which point it cannot be moved up and down. Can you provide a picture of your CW9 with the slide stop removed, showing how the slide stop spring engages the frame? I don't think there are multiple ways it could be installed, but a picture of a functioning weapon would help dispel any concerns there. If necessary, let me know and I'll take a picture of mine and post it.

Thanks again for your great help. I do appreciate it.

[gb6491]

Greg, you are really one of the greatest. Others try to help with links (mostly to your posts), and advice, but you are the only one I know that goes to such great lengths to help a stranger. Thanks for all the great help, outstanding photos and detailed information you provide!

I'm not sure I deserve such a fine accolade, but thank you, I very much appreciate what you have written.

Greg,

I really appreciate the time you've taken with this and the pictures you've shared. I've taken them to the bench and compared them with my pistol. I don't see any discrepancies so far. Let me provide a little more information, based on today's experimentation...

With the pistol field stripped if I put the slide stop back in without the slide in place I can move it "up and down" as if I were locking the slide until I firmly finish putting it in place in the frame. Once it is in all the way it will not move "up and down" as if I were trying to lock the slide to the rear. It moves freely when not all the way in and as I move it towards the fully in position there is a little opposition to moving it up and down until the final "click", at which point it cannot be moved up and down. Can you provide a picture of your CW9 with the slide stop removed, showing how the slide stop spring engages the frame? I don't think there are multiple ways it could be installed, but a picture of a functioning weapon would help dispel any concerns there. If necessary, let me know and I'll take a picture of mine and post it.

Thanks again for your great help. I do appreciate it.

Here's a shot of the spring on my CW9, I apologize for the photo's quality as I seem to be a little shaky with the cell phone this evening.

Though the following are from my CW45, the sping setup is the same and the photos are better quality:



FWIW, when the stop is fully inserted the spring should be in the groove at the base of the pin (see green arrow below). I wonder if the small shelf next to it (red arrows) is causing interference with this or the stops movement. A little polish to the edges of that shelf probably won't hurt anything.


A couple of other thoughts:
1.) When I had a CM9, I obtained the parts to put a PM40 top end on it. It fit fine except that the 40 caliber stop is shaped slightly different from the 9mm stop.
Here's what I wrote about it back then: "The .40 slide stop is different from the 9mm and needed a slight amount of material removed (see red arrows) to clear the cut out in the CM9 frame. This does not affect the contact area for the follower (see green highlight)."

The stop was contacting this side of the frame's window (I could have removed material here, but the stop is less expensive and does not require a trip to the factory for replacement):

As your pistol is a 40 from the factory, it should have proper clearance; still this might be worth a look.

2.) If you have the recoil spring really tightened down, you might back the screw off a little. Here's how I tighten that spring now: https://www.youtube.com/watch?v=c50P7HCAATo

Regards,
Greg

[NWShooter]

Ah ha! Your pictures of the slide stop spring on your CW9 solved the question. My old spring had the end that is supposed to be over the slide stop under the slide stop. I'd post a picture, but I'm not seeing how to do that other than link to a web site, and I don't have my pictures on-line.

Putting the new spring in and ensuring that it looked like your photos solved the problem. Everything appears to be functioning as it should. Thank you for your wonderful help. Your photos showing what it is supposed to look like were far more helpful than the exploded parts diagram in the manual. One more small detail to make sure is right when reassembling the pistol.

Thanks again for your help. One less trip to UPS to ship the pistol to Kahr for them to fix.

[Decado]

That was great stuff Greg, your the man!

[gb6491]

NWShooter,
That's excellent new!

Decado,
Thank you kindly

Regards,
Greg