CW380 (and P380) Modifications

[November]

Here are two reliability mods I've done to my CW380. The first one deals with various bullet shapes making contact with the slide stop as they rise to the top of the magazine. As I don't carry a reload, the last round hold-open function is superfluous to me, so I shaved off the "ledge" on the slide stop that contacts the mag follower until it was flat with the frame. No more problems with contact.





The second mod deals with the trigger hinge pin walking out during firing. I just filed down the lip on the right side of the pin until it was the same diameter as the rest of the pin. After that I was able to insert the pin until I could feel it fully engage the tiny pin on opposite side of the frame that holds it in place. Evidently, the trigger pin wasn't long enough from the factory as it never engaged that tiny pin before. Now it's solidly in there. Hope these mods are helpful to someone else.

[rxs0]

November,

Here is a list of various modifications and upgrades I have performed to improve the reliability of the CW380 pistol.

Here is a good video describing the inner mechanics of the Kahr pistol.
http://m.youtube.com/watch?v=iYRHpolEC_Y

Slide Stop
I also performed the same slide stop modification on my CW380 (serial number RJ38XX). I originally had multiple failures to feed and premature slide locks. I ordered a replacement machined P380 slide stop (not the MIM, metal-injected-molded) from Kahr for $24.20 and filed it as above. It is now very reliable with the CW380 slide and barrel. I used an EdgeCraft Diamond Knife Sharpener (bought at Gander Mountain) as a file. The gun now functions like a Ruger LCP in regards to lack of last round hold-open.
I filed and beveled the top edge of the slide stop for better comfort in releasing slide. The slide stop "pin" which inserts into the frame was also polished.

Barrel
I polished the inside of the CW380 barrel chamber (mostly the upper portion) with a Dremel device for smooth feeding. Feed ramp was already highly polished. I used the included Dremel white cylinder-like polishing "wheel", which I ran/sanded on a file/sandpaper to resize the attachment to fit the chamber.

I minimally deburred the rough thin edge along the right posterior margin of the CW380 barrel hood with a small fine hobby file (from Lowes) and wet dry sand paper. I have had several CW380 barrels with this defect, likely left from the manufacturer's process. Avoid removing too much metal along the hood margins as this could lead to a more loose fit with the slide.
http://www.kahrtalk.com/showthread.p...587#post340587
http://www.kahrtalk.com/showthread.p...817#post184817

Polish the kidney shaped cam on the barrel recoil lug with a Q-tip, dremel, and Flitz.

Magazine
I used fine wet to dry 600 (or finer) sandpaper to smooth inside and outside margins of the magazine lips. I tested multiple magazines for reliability. I picked magazines with followers that move freely without "catching" the inside of the magazine tube. I did not sand down the magazine follower. Magazine springs worked fine.

Slide
I minimally deburred and lightly filed the inferior edge of the anterior margin of the slide ejection port, which slides against the hood of the barrel.

I polished the "ramp" or "cocking lug" along the underside of the slide with wet to dry sandpaper. I also polished the beveled portion of this ramp near the breech face.

If the breechface is rough, consider also lightly polishing it (without effecting headspace) to allow for more smooth feeding.

I polished the inner tracks of the slide. The lower non-rail surface of the slide was also polished with 600 grit sandpaper.

I also mildly polished the front of the slide opening "bushing" for the barrel as well as the opening for the recoil rod (with dremel and Q-tips).

If you're having extraction failures, consider disassembling the slide components and remove any metallic shavings and debris. Also ensure that the extractor pusher (extractor pin-front) moves easily through the channel. I recently bought a P380 slide and noted the extractor channel was tight during reassembly. I pushed the extractor pin-front through the channel multiple times in both directions to remove the spurs. I used a 1/16 punch and the inside ink tube of a pen to push extractor front-pin back and forth in the channel. The extractor appeared intact and free of burrs. Disassembly instructions link is below. Be sure to push down only the far lateral opening of the extractor pin access on the slide back plate. The more medial "opening" is part of the back plate. Use a tiny hobby precision screwdriver for this step. Also check striker channel for metallic debris and spurs.
http://m.youtube.com/watch?v=mi3VFRll2L4
http://www.kahrtalk.com/showthread.p...e-Kahr-s-Upper!
Also consider polishing the "pin" component of the extractor and front and back extractor pins. I did not need to polish or modify the extractor.

If you are having light primer strikes, consider polishing striker, stricker spacer, and striker channel with dremel, Q-tips, and Flitz polishing compound.

I did not need to debur or polish the downward projecting lug of the striker which engages with the cocking cam. The striker block and channel can be polished for smoother trigger pull.

Recoil Rod and Springs
I replaced the current recoil springs with a new set from Kahr. The old set would not allow the slide to return to battery after testing by gently pulling back the slide in the partially cocked striker mode (after completely racking the slide, and not pulling the trigger). Initially, I was unable to install both of the new recoil springs into the gun. I first installed the longer inner recoil spring alone within the gun to "prime" or compress the spring overnight. I was then able to easily install both recoil springs the following day.

I have upgraded the recoil rod to the stainless steel version, without change in reliability.
https://lakelinellc.com/product/stai...or-kahr-cw380/
Polish the recoil rod if the surface is rough.

Frame
I avoided adjusting the slide lock spring and screw on the frame.

I minimally buffed the metallic rails at the back of the frame. Check thin front frame rails for spurs and rough edges.

I currently have not had any problems with the trigger pin backing out of the frame.

I did not polish the (2) bearing surfaces of the pivoting double lobe cocking cam (sear lobe, lobe used to raise striker block). I did not polish the trigger bar.

Lubrication and Cleaning
I run the pistol "wet" with BreakFree CLP or Hoppes' lube at the range and clean the chamber after every 50 rounds. I use a Glock cleaning brush to clean the barrel and chamber.

Ammunition
My pistol runs best with PMC and Federal 380 ACP FMJs. I will be testing other FMJ and hollowpoint loads in future updates.

Holster
I use a custom shark skin rear pocket holster.
http://mecopocketholsters.com/rearpocket.htm

rxs0

Initial Testing:

I had some failures to feed with flat nose White Box Winchester loads when the magazine was loaded with 6 rounds with the CW380 barrel, slide, and frame. This improved with only five rounds loaded at a time. The failure to feed consisted of the round jammed against the lower margin of the barrel feed ramp. As mentioned earlier, I polished the ramp on the underside of the slide to minimize drag on the first round in the magazine. This problem resolved with the P380 barrel as described below in the updates.

Updates:

Update 7/30/2015: I upgraded my CW380 barrel to the P380 match barrel for $140.80 from Kahr.com. I experienced no malfunctions with 50 rounds of PMC 380 ammunition and 30 rounds of Winchester White Box in the modified CW380 pistol (serial number RJ38XX). The P380 barrel hood fits a lot tighter in the CW380 slide than the CW380 barrel with much less side-to-side play. In particular, the tab along the back of the barrel hood fits tighter in the corresponding slide notch near the breech face. I did not need to polish or deburr this barrel.

Update 8/4/2015: I retested an unmodified machined P380 factory slide stop with an unmodified P380 Lothar Walther match grade barrel in a CW380 frame (serial number RJ38XX) for 200 rounds of Federal FMJ without a single malfunction! I now think that the more loose fit of the CW380 barrel (in comparison to the tighter fitting P380 premium barrel) in the CW380 frame may be contributing to the feeding malfunctions. The greater "wiggle" of the looser fitting CW380 barrel may be impeding reliable feeding of the rounds off the magazine. In particular, the side-to-side "wiggle" of the barrel (and hence ramp) may partially deflect the loading round against the slide stop "tab" and result in a misfeed. This would account for the improved feeding with the slide stop modification (grinding down the tab) in CW380 pistols with misfeeds. Regardless of the cause, I improved reliability of the pistol with the P380 Lothar Walther barrel.

Update 8/8/2015: I just tested a new CW380 frame (RH81XX) and an unmodified CW380 barrel with a new P380 slide ($145.20 ordered from Kahr.com). I used an unmodified P380 slide stop and my most reliable 6-round magazine. I deburred and polished the rails and ramp/cocking lug along the underside of the slide. I deburred and minimally beveled/polished the lower edge of the anterior margin of the slide ejection port. I installed all the slide internal components from the disassembled CW380 slide into the P380 slide without problems. This included the back plate (slide back), extractor assembly (extractor, extractor pin-front, extractor spring, extractor pin-back), striker block assembly (striker block, striker block spring), and striker assembly (striker, striker spacer, striker spring, striker spring guide). I had no malfunctions with the first 100 rounds of Federal FMJs. I had one failure to feed with 100 rounds of PMC FMJs. The tip of the round stuck along the top of the middle of the chamber. This would likely improve with polishing the top of the barrel chamber of the new CW380 barrel. I will also lightly polish (without affecting headspace) the slide breech face to allow more smooth feeding.

Update 8/12/2015: I again retested the unmodified machined P380 factory slide stop with an unmodified P380 Lothar Walther match grade barrel in a CW380 slide and frame (serial number RJ38XX) for 50 rounds of Federal FMJ and 200 rounds of PMC FMJ without a single malfunction. I feel extremely confident with this current configuration with Federal and PMC 380 ACP FMJs. This is my current carry pistol. I still need to do some testing with hollowpoints.

[November]

Mag lips is my project for today, thanks for the reminder rxs0! I also bought a machined replacement slide stop, but figured I'd hack on the MIM one for proof-of-concept. Have you had any issues with the trigger hinge pin?

[yqtszhj]

Good post November and welcome to the forum. Yours to rxs0. I've been eyeballing a cw380 for no good reason other than I would like to have one.

I've done the mag feed lips smoothing to every kahr mag I own and it helps. I have a ct9 that may have the trigger pin issue but not sure yet. I've put about 400 rounds through it and just noticed it walking out after the last session. I tapped it back in good and we'll see what hapoens.

[November]

Good post November and welcome to the forum. Yours to rxs0. I've been eyeballing a cw380 for no good reason other than I would like to have one.

I've done the mag feed lips smoothing to every kahr mag I own and it helps. I have a ct9 that may have the trigger pin issue but not sure yet. I've put about 400 rounds through it and just noticed it walking out after the last session. I tapped it back in good and we'll see what hapoens.

Thanks, I bought it on a whim and it's surprisingly accurate and soft-shooting. The trigger hinge pin retention is an odd design, but fixable.

[SlowBurn]

Sort of surprised guys are so willing to sacrifice last round hold-open.

[November]

Sort of surprised guys are so willing to sacrifice last round hold-open.

Reliability is paramount for me. Also, you can always order a new slide stop and put it back to stock if desired.

[Bobshouse]

So Kahr recommends you use the slide release to load the weapon, otherwise you get a jam....and I do, almost everytime I forget. So now after your 6th shot you have to remove the mag, lock back your slide and reload? Much easier to let it lock itself back and slam in a new mag. Im just sayin...

[November]

So Kahr recommends you use the slide release to load the weapon, otherwise you get a jam....and I do, almost everytime I forget. So now after your 6th shot you have to remove the mag, lock back your slide and reload? Much easier to let it lock itself back and slam in a new mag. Im just sayin...

This isn't about "easy". This is about maximizing reliability if you ever need the pistol in a self-defense scenario.

[xsailer]

So Kahr recommends you use the slide release to load the weapon, otherwise you get a jam....and I do, almost everytime I forget. So now after your 6th shot you have to remove the mag, lock back your slide and reload? Much easier to let it lock itself back and slam in a new mag. Im just sayin...

Fortunately my slide always locks back on the sixth round and I remove the mag and put in the loaded one. Never have to pull and lock the slide back except for the first round.

[rxs0]

"Have you had any issues with the trigger hinge pin?"

I have not had any problems with this pin. In regards to the trigger pivot pin, I would try to replace your pin with a replacement pin from Kahr. If your pin continues to back out while shooting, you will need to send the frame back to Kahr for service. In some cases, the frame is out of spec and needs to be replaced with a new frame. This unfortunately will result in a transfer fee.

Continuation of Previous Post:

Good Kahr Frame Disassembly posts:
https://www.ar15.com/archive/topic.html?b=5&f=35&t=102618

http://www.rifle-company.com/phpbb3/...pic.php?t=2347

http://www.**************/forums/kah...-tutorial.html

http://www.gun-tests.com/special_rep...l#.Vcv4M4o8KJJ

Update 8/24/2015: I retested the same CW380 pistol as above with a P380 barrel with 200 rounds of Winchester White Box (WWB) FMJ with only one failure to feed. This setup again consists of an unmodified machined P380 factory slide stop with an unmodified P380 Lothar Walther match grade barrel in a polished CW380 slide and frame (serial number RJ38XX). The malfunctioning round fed almost 2/3 the way in, tip stuck at the top of the chamber. I reloaded the same malfunctioning round into the magazine and encountered the same problem, suggesting an out of spec round.

I finally retested this setup with the same frame, polished P380 slide, and P380 barrel with 200 rounds of WWB with no malfunctions!

During my testing, I noticed the front slide barrel opening crescentic gap (between top of barrel and slide) is slightly larger in the CW380 slide when compared to the P380 slide. The P380 barrel also demonstrated less play when fit into the P380 slide when compared to the CW380 slide. I am not sure if this makes any significant difference in reliability.

[November]

"Have you had any issues with the trigger hinge pin?"

I have not had any problems with this pin. In regards to the trigger pivot pin, I would try to replace your pin with a replacement pin from Kahr. If your pin continues to back out while shooting, you will need to send the frame back to Kahr for service. In some cases, the frame is out of spec and needs to be replaced with a new frame. This unfortunately will result in a transfer fee.

Won't be necessary, it's locked in there good now.

[rxs0]

I have multiple CW380 pistols. I tried the usual greater than 200 round break in. I continued to have multiple premature slide locks and failures to feed.

I ordered multiple P380 machined slide locks and continued to have premature slide locks and failures to feed, even with adequate lubrication and frequent chamber cleaning.

I partially grinded the portion of the slide stop that interfaces with the magazine tab, still allowing for the last round hold-open. Same problems. I tried grinding varying degrees off the slide stop, tried different magazines, but still experienced multiple premature slide locks and failure to feed.

I polished the chamber. Same problems, less frequent. Slide lock spring and screw both looked intact and correctly installed. I did not attempt to adjust frame slide lock spring and screw.

I finally achieved 100% reliability for greater than 200 rounds by grinding the slide stop as posted above. I then tried replacing the now broken in gun (with 100% reliability with over 500 rounds) with a new unmodified replacement machined slide stop. Same problems, less frequent. I had about 1 malfunction (premature slide lock or failure to feed) in about 100 rounds. I tried different frames. Same problems.

I have a CM9 with 100% reliability with 9 mm PMC and Federal FMJs with NO modifications. YMMV. I prefer 100% reliability. My Ruger was 100% reliable out of the box. The CW380 Kahr shoots much better than the Ruger LCP with less recoil. I'd rather carry the Kahr pistol.

If I can't hit the bad guy in 6 rounds, I'm screwed anyways. I am not likely going to have time to reload. The gun has to be 100% reliable.

rxs0

[SlowBurn]

I have multiple CW380 pistols. I tried the usual greater than 200 round break in. I continued to have multiple premature slide locks and failures to feed.

I ordered multiple P380 machined slide locks and continued to have premature slide locks and failures to feed, even with adequate lubrication and frequent chamber cleaning.

I partially grinded the portion of the slide stop that interfaces with the magazine tab, still allowing for the last round hold-open. Same problems. I tried grinding varying degrees off the slide stop, tried different magazines, but still experienced multiple premature slide locks and failure to feed.

I polished the chamber. Same problems, less frequent. Slide lock spring and screw both looked intact and correctly installed. I did not attempt to adjust frame slide lock spring and screw.

I finally achieved 100% reliability for greater than 200 rounds by grinding the slide stop as posted above. I then tried replacing the now broken in gun (with 100% reliability with over 500 rounds) with a new unmodified replacement machined slide stop. Same problems, less frequent. I had about 1 malfunction (premature slide lock or failure to feed) in about 100 rounds. I tried different frames. Same problems.

I have a CM9 with 100% reliability with 9 mm PMC and Federal FMJs with NO modifications. YMMV. I prefer 100% reliability. My Ruger was 100% reliable out of the box. The CW380 Kahr shoots much better than the Ruger LCP with less recoil. I'd rather carry the Kahr pistol.

If I can't hit the bad guy in 6 rounds, I'm screwed anyways. I am not likely going to have time to reload. The gun has to be 100% reliable.

rxs0

Well, as long as it works and you're satisfied. I sometimes carry a spare mag, and feel better knowing it could be brought into play if necessary.

[CharlieR]

My trigger pin seemed to be the same....I have about 800 rounds thru it, and felt the rim of the pin on my trigger finger when holding the gun at ready.
I used a nylon hammer and tapped it back in, but it doesn't seem to be long enough to fully go into the hole on the left side. I was thinking about ordering a new pin, but reluctant to pay $20 shipping on a 2-3 dollar part.