Recoil spring guide rod taking a beating

[Exiledviking]

Did you remember to install the recoil spring with the closed end up against the guide rod flange?

Yes. It was installed correctly. Considering this new P9 has been 100% I'm functioning I'm not too worried about it. As someone pointed out it seems that the very rough ends of the recoil spring caused most of the beating. I'll keep an eye on it as I get more rounds thru it and see how it looks. I am going to look at the breech end of the guide rod to see if there's any beyond normal wear. I'm planning on picking up a K9 as the training and range gun.

[Exiledviking]

I've noticed several problems on the forum lately that make me wonder if some of the problems are for lack of the "notch" that allows the recoil assembly freedom to tilt with the barrel during firing.



The recoil spring assembly batters the rear top inside of the receptacle for the forward part of the RSA and throws the action off... also battering the RSA.

The notch can be added with a round file or careful "machining" with a Dremel or like tool.

The P380 seemed to not require one, but I noticed my 1997/1988 vintage K9 was developing fractures there and I added the notch.

There are more posts on the subject and it is ANOTHER thing to check, as with the beveling of the stripper part of the slide. The PM9 did not need the beveling, as there was plenty of room behind the top cartridge in the magazine for the "stripper" to get behind it.

Wynn

Great info. Next time I pull it apart I will check that area.

[cobrasjp]

The recoil rod is seated in the shelf on the underside of the barrel and moves up and down with the barrel.

The shelf on the underside of the barrel only holds the guide rod assembly until you put the slide assembly onto the frame. As you move the side assembly rearward, the rear head of the guide rod catches on the vertical face of the frame at the back of the recoil spring tunnel. It stays there (and the spring starts compressing) as you keep moving the slide assembly rearward until you insert the slide stop pin.

To verify this, field strip your pistol. Put the barrel on the frame with the slide stop. You should be able to cycle the barrel back and forth like it does during the firing cycle. Then insert the guide rod into the tunnel and try to seat it against the shelf on the bottom of the barrel. It can't even touch the barrel because it will come to rest against the vertical shelf at the rear of the tunnel.

Here's a couple of pictures I just took to show this. In one, the barrel is tilted way up to show the head of the guide rod resting on the frame, just as it does when the gun is assembly. It may be hard to tell, but the guide rod is as far rearward as it will go. When I tilt the barrel back down into it's normal position, it does not touch the guide rod. The other picture is with the barrel in it's normal position. If you look close you can see that the guide rod is not touching the barrel.

https://dl.dropboxusercontent.com/u/...2019.42.25.jpg


https://dl.dropboxusercontent.com/u/...2019.40.24.jpg


The video on Kahr's website with the cutaway K9 shows the guide rod and recoil spring staying parallel to the slide and not tilting with the barrel during the firing cycle. Look at about 1:06 into the video. http://www.kahr.com/patents-video.asp

Not trying to be difficult, but I don't want people to assume something about their Kahr that may not be true.

[Redstate]

Good post, cobrasjp. I tend to agree with you that the flange of the recoil rod rests against the frame. By the way, I did check my K9 (2014 model), and there is no "notch". I also did not notice any kind of wear. I only have a little over 500 rounds through it.

[wyntrout]

No problem, cobrasjp. I hadn't really looked at the action there that closely.

I got my P9 and moved the slide to the rear. The barrel tilts down at the rear and the RSA tilts up a bit at the front as well as the recoil spring is compressed... not much, but measurable ~ 1/32".

I took the slide off and put the RSA into the frame and then the barrel in place with the slide lock pin inserted partially. The guide rod flange does rest on the frame and stays about 1/8" or more forward of the barrel lug. There's a channel in the frame and the flange of the guide rod does rest against the wall at the rear of the channel.



I took some pictures:

http://s1134.photobucket.com/user/wy...%20Positioning





After reassembling the pistol I couldn't remember if it had the notch. I had to take it apart and found that there's no notch... no battering, either, so that seems okay.



Wynn

[marshal kane]

. . . I got my P9 and moved the slide to the rear. The barrel tilts down at the rear and the RSA tilts up a bit at the front as well as the recoil spring is compressed... not much, but measurable ~ 1/32".

I took the slide off and put the RSA into the frame and then the barrel in place with the slide lock pin inserted partially. The guide rod flange does rest on the frame and stays about 1/8" or more forward of the barrel lug. . .

Wynn

It doesn't work that way with my P9 which I bought new last year. On my P9, the RSA is captured on a shelf that is part of the barrel lug and it stays there. After a range session with my P9, removal of the slide finds the RSA still abutting the shelf on the barrel lug. Movement of my barrel during recoil doesn't move the RSA down into the frame. This coincides with the P9 disassembly/assembly video instructions at the Kahr site. I can see by your photos that the flange on your RS guide once placed in the frame, cannot move up to the barrel lug so it concerns me should you attempt to fire your P9 with the flanged end of the RSA in the frame. I would suggest you review the Kahr video, see if your barrel lug has a shelf for the RSA, fit the RSA there, assemble your P9 and cycle the pistol unloaded for functionality. Not saying that your P9 couldn't be different from mine and that you aren't correct about the RSA abutting in your frame, I'd feel irresponsible by not bringing this up to you.

[cobrasjp]

It doesn't work that way with my P9 which I bought new last year. On my P9, the RSA is captured on a shelf that is part of the barrel lug and it stays there. After a range session with my P9, removal of the slide finds the RSA still abutting the shelf on the barrel lug. Movement of my barrel during recoil doesn't move the RSA down into the frame. This coincides with the P9 disassembly/assembly video instructions at the Kahr site. I can see by your photos that the flange on your RS guide once placed in the frame, cannot move up to the barrel lug so it concerns me should you attempt to fire your P9 with the flanged end of the RSA in the frame. I would suggest you review the Kahr video, see if your barrel lug has a shelf for the RSA, fit the RSA there, assemble your P9 and cycle the pistol unloaded for functionality. Not saying that your P9 couldn't be different from mine and that you aren't correct about the RSA abutting in your frame, I'd feel irresponsible by not bringing this up to you.

The shelf on the underside of the barrel is just meant to hold the RSA in place as you assemble the gun. It doesn't stay there all the time. The RSA sits on the shelf on the underside of the barrel until the slide assembly is almost all the way on the gun. As it nears the normal battery position, the frame catches and holds the bottom part of the head of the RSA. When you take the slide assembly off the gun, the head of the RSA transfers back to the barrel and it may appear as if it had stayed there when the gun was assembled and fired.

If what you are saying is true, you should feel no spring tension on the slide when you are aligning the marks to put the slide stop in during assembly. You would only feel spring tension after the barrel unlocked from the slide and there was relative movement between the slide and the barrel/RSA.

One way to tell is to apply some white paint to the vertical part of the frame where I contend the RSA bears against when the gun is assembled. Then shoot it. If I'm right, the paint should show witness marks.

Also, try what I show in my pictures. Use the slide stop to hold the barrel to the frame. Hold the barrel in the same position it would be in if the slide were present. Then try to see if you can even get the head of the guide rod (don't need spring) to touch the shelf on the underside of the barrel. Can't come close to touching. So the RSA can't possibly be resting on the shelf on the underside of the barrel when the gun is assembled.

[marshal kane]

OMG, you're RIGHT! I took another look and see what you mean. Even an old dog can learn a new trick. Thanks!

"If what you are saying is true, you should feel no spring tension on the slide when you are aligning the marks to put the slide stop in during assembly. You would only feel spring tension after the barrel unlocked from the slide and there was relative movement between the slide and the barrel/RSA."