Kahr design flaw?

[A-R]

http://www.thebangswitch.com/flaw-in-the-kahr-cm9/" onclick="window.open(this.href);return false;

The flaw I’m talking about can be seen in the picture below. It shows the front of my CM9 with the guide rod slightly protruding from the front of the slide.  While it seems as though this is perhaps nothing more than cosmetic inconvenience, it’s actually quite a bit more serious than what you might think.

This condition will occur when you either ride the slide home gently, or worse, when you push the slide back slightly while it’s loaded and ready to go (or so you think).  Why is this a problem?  With the firearm in the condition you see above it’s non-functional.  If you pull the trigger the striker will fall forward taking the slide home with it and forcing the tip of the guide rod to fall back into alignment with the face of the slide.  The only problem is that this robs the striker of critical inertia and doesn’t leave it enough oomph to ignite the primer.  Not a big deal, right?  Just “sling shot” the slide, or use the slide stop to release the slide per the instructions in the user manual when you load the gun and all should be good.

Not quite.  If you place the pistol in a holster and the friction from it being inserted causes the slide to move back ever so slightly, the tip of the guide rod will pop into the state pictured above and render the firearm inoperable.  You won’t be able to tell the gun is in a non-functional state until you remove the gun from the holster.  That means once you holster the pistol you never know if it’s going to work with you draw it.  If you carry the gun in a pocket without a holster (not advisable) you can easily knock the slide back causing the weapon to enter this disabled state.

[Jumping Frog]

Any semiauto handgun that does not have a safety keeping the slide in position is vulnerable to something pushing the gun out of battery. Once out of battery, a gun should not fire. If an out-of-battery gun will fire, that is the safety issue.

[xb12s]

Interesting. But, and this is a big one, he didn't contact Kahr, he doesn't know if this problem exists in later production models, etc, so I can't draw a complete conclusion as to whether this is a design flaw or just a one-off problem. Sounds like a design flaw, but one that would be made right if he contacted Kahr. I'll look at my PM9 tonight, but I don't think it has the cap.

Kahrtalk forum would be a good place to post this as well if you're a member there.

[gigag04]

Any real world failure reports?

[xb12s]

My PM9 has the same button on the end of the guide rod rather than the straight wall design pictured on the CW9 in the article. I cannot get mine to lock up out of battery. I tried with snap caps and empty.

I quickly found at least 3 threads on Kahrtalk with this issue. A couple people had success in eliminating the issue with light polishing and extractor pin work. ??

I'd have tried a polish and if that didn't work, called Kahr before sending it to the back of the safe.

[03Lightningrocks]

I have a very well used PM9. It is about six years old... Maybe. I tried to get it to replicate that issue and cannot. Maybe because it is broken in. That is a disconcerting situation for sure. I have been waiting for better financial times to buy the PM40. I hope this is a one off situation or at least a cw only issue.

[mr surveyor]

Any semiauto handgun that does not have a safety keeping the slide in position is vulnerable to something pushing the gun out of battery. Once out of battery, a gun should not fire. If an out-of-battery gun will fire, that is the safety issue.

Exactly!

No matter what handgun I'm "holstering", whether a semi-auto (striker fired or hammer fired) or a revolver (hammer fired), my thumb is always firmly on the hammer or the back of the hammer or slide. Simple fix to a non-problem. I have two Kahr handguns that are no more prone to holster "out of battery" than any other semi-auto I have (or have ever had)

surv

[TexasGal]

After reading the article, I have a question. I understand the problem being pointed out. I also reholster with my thumb stabilizing the slide from being moved out of battery--especially if the holster is snug. But my question is shouldn't every semi-auto be designed to allow you to do a chamber (press) check and return to a condition ready to fire? I can't count the times I have chamber checked various guns and they fired afterwards every time. I don't own a Kahr. Is this an isolated problem or can it be an issue with other guns that have been chamber checked? If the guide rod is not protruding as shown in the article, then there should be no problem, correct? Inquiring minds want to know.

[maverick2076]

I have a CW9, and I've never had this issue, nor have I been able to replicate it myself.

[xb12s]

After reading the article, I have a question. I understand the problem being pointed out. I also reholster with my thumb stabilizing the slide from being moved out of battery--especially if the holster is snug. But my question is shouldn't every semi-auto be designed to allow you to do a chamber (press) check and return to a condition ready to fire? I can't count the times I have chamber checked various guns and they fired afterwards every time. I don't own a Kahr. Is this an isolated problem or can it be an issue with other guns that have been chamber checked? If the guide rod is not protruding as shown in the article, then there should be no problem, correct? Inquiring minds want to know.

I'm not clear on what you mean by chamber check. Are you saying that you partially pull the slide back enough to peak into the chamber without extracting?

Yes, this is an isolated problem, only reported on Kahr CM9 model with the button on the end of the guide rod where tolerances didn't align just right and that resulted in parts not being able to slide past one another. The PM9 and presumably the CM40 and PM40 have the same guide rod. I would not worry about it all if you don't have those specific Kahr models.

I have a CW9, and I've never had this issue, nor have I been able to replicate it myself.

CW9 is not affected. It has a different design on the guide rod and spring. The article has a picture showing the difference.

[TexasGal]

Xb12s asked TexasGal:

I'm not clear on what you mean by chamber check. Are you saying that you partially pull the slide back enough to peak into the chamber without extracting?

Yes exactly. Just checking that way when I don't want to extract a live round that will then have to be rechambered later and increase the possibility of setback on the bullet.

[Excaliber]

http://www.thebangswitch.com/flaw-in-the-kahr-cm9/

The flaw I’m talking about can be seen in the picture below. It shows the front of my CM9 with the guide rod slightly protruding from the front of the slide.  While it seems as though this is perhaps nothing more than cosmetic inconvenience, it’s actually quite a bit more serious than what you might think.

This condition will occur when you either ride the slide home gently, or worse, when you push the slide back slightly while it’s loaded and ready to go (or so you think).  Why is this a problem?  With the firearm in the condition you see above it’s non-functional.  If you pull the trigger the striker will fall forward taking the slide home with it and forcing the tip of the guide rod to fall back into alignment with the face of the slide.  The only problem is that this robs the striker of critical inertia and doesn’t leave it enough oomph to ignite the primer.  Not a big deal, right?  Just “sling shot” the slide, or use the slide stop to release the slide per the instructions in the user manual when you load the gun and all should be good.

Not quite.  If you place the pistol in a holster and the friction from it being inserted causes the slide to move back ever so slightly, the tip of the guide rod will pop into the state pictured above and render the firearm inoperable.  You won’t be able to tell the gun is in a non-functional state until you remove the gun from the holster.  That means once you holster the pistol you never know if it’s going to work with you draw it.  If you carry the gun in a pocket without a holster (not advisable) you can easily knock the slide back causing the weapon to enter this disabled state.

This is good to know about and something to check.

However, it seems to me the guy who reported the problem on the other forum has spent a lot of time and effort moaning and obsessing about the problem instead of fixing it. One of the later forum posts on the linked page above reported that the owner did the most logical thing: he called Kahr and had a new guide rod and spring assembly sent to him.

Problem solved.

[03Lightningrocks]

I never do a chamber check because I never empty the chamber. Unless I fire the gun. I feel certain the elves aren't going to take the round out of my gun over night.

[The Annoyed Man]

I never do a chamber check because I never empty the chamber. Unless I fire the gun. I feel certain the elves aren't going to take the round out of my gun over night.

Now that there is funny.

I recently traded in a CW45 as part of the deal when I bought my XDS, but my wife has a CW9, and I still have a PM9. The CW9 has a straight rod with no cap on the end. I'm pretty sure that the CW45 was the same. I just examined my PM9, and it has the cap on the end, but the edges of that cap are chamfered (I guess that would be the term) so that they are "bell-shaped," with the larger diameter at the end. I have never experienced a failure of any kind while shooting this gun, but I bought it used. I bought it in June of 2011, and when I called Kahr with the serial number to ask about the date of manufacture, they told me December of 2004, so this gun is nearly 9 years old. I don't know if the design has been updated in any way since then. In any case, I've never had a problem with it.

Here is a picture of the design I grabbed off of Google:


I think the reason for the design is this: I'm pretty sure that it is actually threaded onto the end of the guide rod. The reason it is threaded is to give access to the captive smaller spring when changing out spring sets. In any case, after looking at my own PM9, it's easy to see why it has never had this kind of failure. The chamfering/belling of the end cap would prevent it from ever getting hung up on the edges of the hole in the slide.

Here's a couple of closeups I shot with my cellphone. Please forgive the fuzziness, but they are clear enough to see the chamfering and belling I'm talking about. You can see that the end caps are not cylindrical.

Perhaps since it threads on, you could measure the ID of the hole on your CM9 against the hole on somebody's PM9, and if they're the same you could order the PM9 end cap and put it on your CM9 pistol?

Instructions for swapping them out: http://glocktalk.com/forums/showpost.ph ... ostcount=5