CW45 (and other poly Kahr pistols): issues and fixes

[gb6491]

These methods and solutions might not be best for everyone and as such are not intended to be “how to” articles. Proceed at your own risk!
If in doubt, let Kahr do the work.

BTW: If anyone else has some tips, fixes, upgrades please feel free to post them here

Index: (some posts have multiple subjects in them, so please scroll to find the issue you are interested in):

Very useful links:
How To "Detail Strip" the Kahr's Upper!
also: http://naws.com/Kahr_Slide.pdf
Kahr Polymer Frame Disassembly (Tutorial)
Disassembly/Reassembly Of the Kahr P45 Pistol
Kahr Trigger Install

BARREL
Chamber too tight/...maybe not: see post#77
http://www.kahrtalk.com/showthread.p...745#post354745

Mangled barrel hood: See Post# 58 and 12
http://www.kahrtalk.com/showthread.p...4757#post24757
http://www.kahrtalk.com/showthread.p...8830#post88830

FRAME
Ejector differences: see post# 24
http://www.kahrtalk.com/showthread.p...4742#post44742

Grip too rough: see post#79
http://www.kahrtalk.com/showthread.p...219#post357219

Magazine latch spring installation: see post# 2
http://www.kahrtalk.com/showthread.p...5667#post15667

Short Front Rails (Excessive front end play when the slide is in "battery"/forward): see post# 72
http://www.kahrtalk.com/showthread.p...968#post306968

GUIDE ROD
Difficulty with recoil spring/guide rod installation (aka guide rod bevel issue): see post# 22
http://www.kahrtalk.com/showthread.p...0427#post40427

Protruding/sticking out from front of slide: see post# 22
http://www.kahrtalk.com/showthread.p...0427#post40427

MAGAZINE
Difficulty inserting magazine or stripping first round: see post#4
http://www.kahrtalk.com/showthread.p...5671#post15671

Drops prematurely: see post# 42 & 80
http://www.kahrtalk.com/showthread.p...7289#post67289
http://www.kahrtalk.com/showthread.p...130#post360130

Flush fit: see post# 6 (or go directly to this thread: http://www.kahrtalk.com/showthread.p...5674#post15674 ) also see post#43
http://www.kahrtalk.com/showthread.p...5674#post15674
http://www.kahrtalk.com/showthread.p...7816#post67816

Nose dives: see post# 19
http://www.kahrtalk.com/showthread.p...0416#post40416

Spring installation: see post# 19
http://www.kahrtalk.com/showthread.p...0416#post40416

OPERATIONAL ISSUES (Not covered otherwise, with a few possible repeats )
Failure to return to battery, failure to chamber: see post#77
http://www.kahrtalk.com/showthread.p...745#post354745

Failure to chamber or RTB, possible extractor issue: see post# 78 (especially for .380 pistols, see tigman250's fix )
http://www.kahrtalk.com/showthread.p...748#post354748

First round not feeding: see post#4
http://www.kahrtalk.com/showthread.p...5671#post15671

Jamming: failure to feed, slide hard to rack with trigger held back: see post#76
http://www.kahrtalk.com/showthread.p...743#post354743

Last round jams: see post# 3
http://www.kahrtalk.com/showthread.p...5669#post15669

Light strikes: see post# 26
http://www.kahrtalk.com/showthread.p...9101#post49101

Problems with " failure to feed, failure to eject and failure to go fully into battery, not to mention no trigger reset.": see post# 75
http://www.kahrtalk.com/showthread.p...740#post354740

Slide stuck with live round: see post#77 (this describes a potential cause. Here's a method to clear it: https://www.youtube.com/watch?v=jZdyPdlzEPs )
http://www.kahrtalk.com/showthread.p...745#post354745

RECOIL SPRING
Installation: see post# 22
http://www.kahrtalk.com/showthread.p...0427#post40427

SIGHTS
Front sight installation: see post# 27
http://www.kahrtalk.com/showthread.p...4961#post54961

Night sights: Kahr has Trijicon night sights for the CW45. More options from Dawson Precision & XS Sights (call for option that doesn't require cutting a dovetail)

Installation of the Trijicon sights: see post #74 and 63
http://www.kahrtalk.com/showthread.p...738#post354738
http://www.kahrtalk.com/showthread.p...0890#post90890

Trijicon front sight not flush or sight broke off: see post #63
http://www.kahrtalk.com/showthread.p...0890#post90890

SLIDE
Installation: see post# 6
http://www.kahrtalk.com/showthread.p...5674#post15674

Notch or damage to front of slide between barrel and recoil spring openings: see post#9, 11, 12
http://www.kahrtalk.com/showthread.p...5790#post15790
http://www.kahrtalk.com/showthread.p...5876#post15876
http://www.kahrtalk.com/showthread.p...4757#post24757

Pickup/stripper rail bevel (difficulty inserting magazine or stripping first round): see post#4
http://www.kahrtalk.com/showthread.p...5671#post15671

Slide locking back prematurely (locking back with rounds still in the magazine): see post#5
http://www.kahrtalk.com/showthread.p...5672#post15672

Slide not locking back: see post# 19 (magazine spring orientation)
http://www.kahrtalk.com/showthread.p...0416#post40416

SLIDE STOP
Popping out: see post# 5 (or 26, both concern adjustment of the slide stop spring), 18, 72
http://www.kahrtalk.com/showthread.p...5672#post15672
http://www.kahrtalk.com/showthread.p...9101#post49101
http://www.kahrtalk.com/showthread.p...6297#post26297
http://www.kahrtalk.com/showthread.p...968#post306968

Reduced profile: see post# 5
http://www.kahrtalk.com/showthread.p...5672#post15672

SLIDE STOP SPRING
Installation/replacement: see post# 25
http://www.kahrtalk.com/showthread.p...4744#post44744

Adjustment: see post# 26
http://www.kahrtalk.com/showthread.p...9101#post49101

continued below...

[gb6491]

TRIGGER
Not resetting: see post# 38
http://www.kahrtalk.com/showthread.p...3472#post63472

Not resetting when warm: see post# 71
http://www.kahrtalk.com/showthread.php?1612-CW45-%28and-other-poly-45%29-issues-and-fixes&p=169924#post169924

Not dropping or resetting: see post#75
http://www.kahrtalk.com/showthread.p...740#post354740

[gb6491]

Last round jams:
The problem is very well documented in this post ( http://kahrtalk.com/showthread.php?t=1290 ) by gj47 in regards to his PM45:


"The malfunctions occurred on the last round fired and cannot be cleared quickly. Notice that the casing was pulled into the mag feedlips and wedged into mag and ejection port area. The mag cannot be removed until the casing is pried out. The feed lips of this mag are now bulged about 6 thousandths."

My fix as posted on another forum:
“I've had two major issues with my CW45 and modifications to the magazine have fixed both.
FWIW, the other problem began at about the 500 round mark; the last round would fail to eject cleanly: sometimes getting jammed back down into the magazine. What I found was that the magazine lip on the ejector side was tipping the last round in the magazine slightly upward and slightly off the extractor before it got to the ejector in the ejection cycle. When this happens the case often does not clear the ejection port and gets driven back down into the magazine or barley ejects (more like falls). With rounds still in the magazine, spent casing are (usually) held high enough by the following rounds that this would rarely happen.
To counter this (a new extractor and spring might fix it), I decided to take some material off the magazine lip. I was pretty aggressive on the first magazine; I cycled a spent casing by hand and removed material until I felt the casing would stay in place long enough to hit the ejector. I took less off the next magazine and it seems to function fine. I imagine, with some patience and testing at different stages in the process that even less material would need to be removed. No more FTE issue with the modified magazines: also, they hold the rounds securely and I've had no feed issues with them (I've even dropped them a couple of times with no lost rounds).
Stock magazine and modified magazine (right):

Modified magazines: the second one done is in the background; the modification on it closely follows the contour of the stock feed lip on the other side of the magazine:

I'm not saying this will work for all; it's just something to consider if someone's gun is malfunctioning as described above (again, this just how I did it; not a "how to" article).”

to be continued...

[gb6491]

Difficulty inserting magazine or stripping first round:
Wyntrout describes (with photos) the problem very well in this post about his PM45:
“I found the reason for the "crunch". After after comparing PM45 parts to their PM9 counterparts and screwing with a lot of the parts of the PM45 that I shouldn't have, I tried sticking loaded magazines in each and trying to see a difference. I found a big one. Look at the first 2 photos #43 and #48. These are of the PM9 with a loaded magazine inserted. Notice that there is about 3/16" between the rear of the cartridge and the striker housing and the lower ridge of the slide that strips the rounds off the magazine as the slide returns to battery position.
Now look at the next 2 photos of the PM45 with a loaded magazine inserted and locked in place. There is NO clearance and the ramp/stripper/striker housing is resting on top of the base rim of the cartridge. This is why when the slide is released the stripper rides over the cartridge pushing it back down into the magazine and you have an empty chamber and a scratch on top of the cartridge. The magazine IS locked into place, but by squeezing the top of the slide and the bottom of the magazine hard enough the stripper mashes the rim which gives enough that cartridge is pushed forward of the stripper. That was the "crunching" sound.
Clearly something is wrong here. Both pistols have the slide locked to the rear and there is a big difference in the gap on the PM9, or lack of one in the PM45.
You guys with PM45s please look and see if there is a gap in your pistol between the rear of the cartridge and the stripper/striker housing. This is a big flaw and I think the magazine well is too far aft at the top or some other things are wrong. This sucks!
Wynn

I added a 5th photo of the top round in a magazine which gets scraped as the "stripper" rides over it. This happened a lot."

Attached Thumbnails (see thumbnails here: http://kahrtalk.com/showpost.php?p=13828&postcount=11 )

Note: Basically, the top round is getting trapped under the slide (Wyntrout photo):


My fix: http://kahrtalk.com/13845-post21.html

...
As an emergency measure, I could very slightly round the bottom of the "stripper" but that might screw something else up. This isn't an emergency, though....

Actually, that's sort of what I did to fix the same problem (actually, I could not get my magazine to seat) with my CW45. I slightly changed the angle that the slide is beveled to where the rim of the round contacts it.
In the photo below, I stoned the bevel so that the tailing edge of it is moved further rearward (red arrow). I did not change the starting point of the bevel (green line).

The magazine now cams/rocks forward into place: the top round ready to be stripped out of the magazine. In the photo below, the shot on the left was taken just as the round contacts the slide; on the right, shows the magazine seated:

A quick movie of the action:
YouTube - slidemod.MPG

Sorry about that, can't help myself.

In your video, after the magazine seats it looks like the case rim is tight against
the breech face (proper term?). Will the slide move any farther back from lock?
SWAG that the slide lock might be at fault? Bevel looks like a good fix.

Wondering if your slide's rearward travel is restricted somehow, don't know enough about it,
is there a buffer? Couldn't be dirt on a brand new piece, maybe a burr? You've had it
apart, probably would have seen that.

PM40 suggested technique is to lock slide, insert mag, release slide.
When new, mine wouldn't feed cycling by hand, only by releasing the slide lock.
Tried it again recently, now it works by hand.

Once the magazine seats there is a little space between the round and the breech face:

The slide can be moved a little further back: enough to release the slide lock.
I have another slide lock (a MIM piece), but there looks to be no difference in position when it is installed.
No buffer, there's nothing I've seen that looks like it's limiting the slide's travel. I did this tweak some time ago and have had not had the problem since (I'm up to about 750 rounds through it).”

to be continued...

[gb6491]

Reduced profile slide stop:
Some info here:http://kahrtalk.com/showthread.php?t=1099
http://kahrtalk.com/showthread.php?t=3304

Same here, I used a Dremel to knock down the sharp edges and corners on my slide stop.

Regards,
Greg

Even more reduction (somewhat following Jocko's lead here http://kahrtalk.com/showthread.php?t=859):

Compared to an unmodified stop:


Slide locking back prematurely (aka locking back with rounds still in the magazine):
I first thought this is to be an operator issue, so I removed some material from the stop lever to make it smaller and reduce the chances that I was inadvertently hitting it when the gun recoiled (see above). I'm not sure how much this helped as the problem still persisted.
The slide stop on my CW45 was always very easy to remove from the pistol; so much so, that if a round nose dived enough while feeding it could pop the stop out from the frame. My first fix for this was to remove some material from the stop where a nose diving round would impact it. This did fix this issue, but I still had intermittent problems with the slide locking back with rounds still in the magazine. I decided to also remove some material from the stop where rounds might contact it when feeding from the magazine. This has fixed premature slide lock problems in other Kahr poly guns, http://kahrtalk.com/showthread.php?t=6066 (you might also want to see this video: http://www.youtube.com/watch?v=ph41eu-7IgI ), but was not quite as effective in my gun.
I now believe that the slide stop spring may have played a greater role in both issues than the stop itself. I had an extra slide stop spring and decided to install it to see if it made any difference in how easy my stop was to remove.

A note here: if replacing the spring, don't remove the screw holding the spring and washer in place completely out of the frame; just loosen it enough to remove the spring. This will greatly reduce the chances of stripping the threads in the polymer frame. (see how I did it here:post #25 in this thread.)

Upon removing the spring, I compared the old and new: finding that that old had some wear marks on it where the stop contacted it, but otherwise they were identical. After installing the new spring, I did some experimenting with the screw that holds it in place (Note: I was very careful when doing this so as to not over torque the screw and damage the frame). I found that by tightening it just to the point that the spring seems to operate as two distinct springs (where before, the whole spring seemed to move easily as one) made for a much tighter fit of the slide stop. I say seems becuase you may not be able to eliminate all movement along the length of the spring, but just limit it how easily it's done. YOU DO NOT WANT TO OVER TIGHTEN THIS SCREW. I then loosened the screw until the spring would move freely as it had done before; this resulted in the stop being as easily removed as it previously had been. I played with how tight the screw was until I found a median that I liked; leaving it just tight enough that the springs travel seems to mimic two distinct springs and the stop is tight enough that I need to use something to start it out of the frame (though I can do it by hand if need be). My CW45 functions perfectly with the spring adjusted this way: no more inadvertent "lock backs" or the stop being pushed out of the frame by nose dives. Again, this is just what worked for me and how it did it, not how to do it.

Here's a video to better explain (hopefully) how I tightened the slide stop spring screw: http://www.youtube.com/watch?v=c50P7HCAATo

Later on: I found this posted about tightening the slide stop spring:

“I also called tech support to get the proper way of setting the screw and they said:
The spring looks somewhat like a G and that the screw should be tight enough that the top and left part of it do NOT move. If I understood him correctly, the bottom perhaps from 6 o'clock and going counter clockwise should move and that the rest should be clamped down.” (http://kahrtalk.com/showpost.php?p=3...stcount=post20)

This seems to verify what I found when replacing my slide stop spring.
FWIW: I've been running my larger slide stop (unmodified lever) since replacing the spring (and tightening it as described above) and have not experienced any more premature locking back of the slide (or the slide stop being pushed out by nose dives).

Slide stop popping out:
Slide stop pops out when firing or chambering a round.
Tightening the slide stop spring screw (as detailed above) may solve this issue for you.


to be continued...

[gb6491]

Reinstalling the slide:
My CW45 has always required a slight manipulation of the trigger during reassembly.
The rear of the slide first encounters a slight resistance, then passes over the cocking cam; at this point, the slide's position is quite similar to that in the OP's photo and cannot be moved any further rearward. Pressing the trigger lightly at this point allows the slide to continue backward a slight amount and the slide stop can be installed. I believe the slide is catching on the trigger bar and the slight movement of the trigger frees it up for the remainder of the required distance. The gun operates fine when fully assembled.
Video of the sequence required on my pistol:
YouTube - cw45.WMV
Regards,
Greg

Flush fit magazine:
See this thread: CW45/P45: Flush fit magazine - UPDATED

[Vinikahr]

Reinstalling the slide:
My CW45 has always required a slight manipulation of the trigger during reassembly.
The rear of the slide first encounters a slight resistance, then passes over the cocking cam; at this point, the slide's position is quite similar to that in the OP's photo and cannot be moved any further rearward. Pressing the trigger lightly at this point allows the slide to continue backward a slight amount and the slide stop can be installed. I believe the slide is catching on the trigger bar and the slight movement of the trigger frees it up for the remainder of the required distance. The gun operates fine when fully assembled.
Video of the sequence required on my pistol:
YouTube - cw45.WMV
Regards,
Greg

In addition to the stickies posted at the top of this forum, I found this a good read:
Disassembly/Reassembly Of the Kahr P45 Pistol

Thanks for sharing, glad things are working out!

[Bawanna]

Good stuff, you really put some effort into this. Thanks.

[wyntrout]

gb6491, I would add that Kahr's "fix" of beveling the "stripper" doesn't move the cartridge, it pushes on the rear of the cartridge and moves the top of the magazine forward while the cartridge remains all the way to the rear of the magazine. I checked and double-checked that. Evidently there is a bit of extra space (or slop) in the top of the magazine well. The bevel and a new ejector seemed to fix everything, including the spent cases being ejected at my forehead. I will wear my Kahr cap every time I go to the range now, as well as shooting glasses.
The missing "notch" for the recoil spring movement in the front of the slide is a biggie, too. Some guys have chosen to "machine" that as it should be instead of sending it back to Kahr... especially if you have to pay the shipping.
Nice post. Thanks.
Wynn
The thin metal unmachined notch area:

http://kahrtalk.com/showthread.php?t=1144

The notch as it should look:

http://kahrtalk.com/showthread.php?t=1368

[gb6491]

gb6491, I would add that Kahr's "fix" of beveling the "stripper" doesn't move the cartridge, it pushes on the rear of the cartridge and moves the top of the magazine forward while the cartridge remains all the way to the rear of the magazine. I checked and double-checked that. Evidently there is a bit of extra space (or slop) in the top of the magazine well. The bevel and a new ejector seemed to fix everything, including the spent cases being ejected at my forehead. I will wear my Kahr cap every time I go to the range now, as well as shooting glasses.

Wynn,
You are correct, though the cartridge moves a very slight amount (at least in my pistol), the movement of the magazine is what makes this modification work. I've edited my earlier post to more accurately reflect this; thanks for bringing it up I must say I was a little relieved to see that Kahr's fix on your gun mirrored what I had done on mine earlier.
Regards,
Greg