finally a guide rod question

[olympicmotorcars]

I have one more question and I will try to quit bothering everybody about my problems for awhile.

My PM 40 has started denting the guide rod. ( I would like to post a pic but dont know how )

I noticed this about 1 year ago, the larger part of the guide rod ( that the big spring fits around ) developed a dent in the middle of it. I replaced the guide rod assembly with a new one and it did the same thing. when I sent my gun into Kahr because it was breaking followers, they replaced it with a third one.
After going to the range last Saturday, I noticed it was beginning to develop a dent also.

Anybody else have this problem? What in the world could cause it?

[TucsonMTB]

Yeah, one of my two PM40's does that too. It happens with just one of the two, even though they are both PM40's and are maintained the same way and shoot the same ammunition. I have a theory the spring is denting it during recoil.

I usually insert the recoil assembly in the same position each time a pistol is put back together, with the end of the last coil on the side closest to the barrel. I started doing that a long time ago when one of the recoil assemblies started hanging up on the outside of the slide occasionally. The gun still worked fine, but it looked odd when it happened. Positioning the spring as described reduced the frequency of the hang-ups. I eliminated that behavior by replacing that offending recoil assembly, but kept the practice of aligning both of them the same way each time the gun goes back together after cleaning.

As a result, I have a single, short indentation on one side of one of the recoil assemblies that lines up perfectly with the coils of the spring in that area. It is near the center of the area covered by the outer recoil spring.

If that is similar to what you are experiencing, you might replace the outer spring, or the entire assembly to see if it stops. My conjecture is that the spring is flexing on recoil and impacting that relatively thin metal tube, thus denting it.

In my case, the dent is not very deep. I believe recoil assemblies are consumables and should be replaced whenever you feel they are creating a problem. Both guns run flawlessly and have for hundreds of rounds, so I won't worry about the denting unless it starts to cause a problem. YMMV ;)

[garyb]

Yes, it is easy to see how the spring could dent or wear the guide rod if you are not greasing it. I apply a good coating of Mil Com grease (not oil) on the guide rod in all locations the spring will slide. Grease will prevent the recoil spring from hanging up and allow it to work smoothly. It is good to "Grease" any part that slides. Grease stays put, allows the parts to work smoothly without wearing as much. I know this may be unnecessary with some guns, but it is common sense with a tight gun like Kahr. Give it a try and you will see what I mean.


Also, rotating the location of the spring with each cleaning (and consequently the guide rod position), will keep it from wearing the guide rod in any one location. Kind of like rotating your car tires. You reposition the guide rod so it will wear more evenly and not just in one location. JMO.


Once the wear starts to get to be noticeable in one spot, the spring will begin to catch that spot and ride the "guide" rod abnormally. Think about it. Start with new parts and keep the "guide" rod smoothly greased. By keeping the wear points minimal the spring will glide, compress and expand across it effortlessly, as it should. To me, wear points on the guide rod indicate lack of a well lubed surface and failure to consciously rotate (or reposition) the guide rod when reinstalling it after each cleaning. I noticed this as potential wear area very early in the game and I've not had any guide rod problems nor failures with my PM40 by practicing this simple operation. It gets shot a lot. Hope this helps you.

[jocko]

I like Remington Dry lube spray, no mess. Like recoil springs guide rod assembly in some guns that seem to produce ore wear than utters is just a replaceable part of doin business. I would think it would take a good 1000 rounds plus to startto really show some critical wear o a kahr guide rod and certainly lube has to help that to, but in a 40 cal, that is a lot of shooting to. that ain't no pu$$y caliber in these small ass guns, something is gonna tqake the brunt of the 40 cal going bang and maybe it just might be your guide rod taking some of that brunt.If u cold see that kahr 40 call work in slow motion, u would wonder how in the hells it stays togetyher even..

what u can try to is goin to wolffs gunsprings and lookingin the PM kahr section, the 40 cal and the 9mm PM all take the same outter recoil spring, and as u can see your PM40 has the same 18# recoil spring as the PM9 does, to me that never made alot fo sense as there is certainly a big ddiffer3encein felt recol. That site also shows the 20.5# recoil outter spirng. that is what I would put on my PM40 for darn sure. It might help that guide rod wear and might help felt recoil. certainly can't hurt a darn thing.

Also whether ur kahr is the new version (beveled front slide) or the ol style blunt nose verstion. They all now take the same outter recoil spring that wolffs sells in their webb site..

[berettabone]

Replacing the rod and spring was the first thing I did with my Kahr. A lot easier to deal with the Wollf combo.

[jocko]

Replacing the rod and spring was the first thing I did with my Kahr. A lot easier to deal with the Wollf combo.

clue me in on this, IU didn't know wolffs made a different guide rod set up for the PM and cm series. I knew they offered sumpin the thge MK series..

[olympicmotorcars]

Wow, many things I did not know about recoil spring assemblies. Thanks everybody.

[berettabone]

clue me in on this, IU didn't know wolffs made a different guide rod set up for the PM and cm series. I knew they offered sumpin the thge MK series..
You are correct............I didn't mean to mislead the op.............springs they got, rods, not................I feel so " sheepish."