A used P380: the good, the bad, the ugly, and a happy ending.

[gb6491]

Well, a while back I bought a used P380. The shop let me shoot a few rounds through it and all was good. It fed and ejected without issue plus I was accurate with it.

The bad: fast forward about 50 rounds after I purchased it and I started to get light strikes. I did a quick visual and it appeared that the striker spring had failed.
The shop's new gunsmith verified it and said he'd get a spring on order. I decided to do likewise along with some spare parts. I received my parts in good order from Kahr. That was a good thing because the gunsmith dropped the ball on his order. I installed the new spring, but continued to have some light strikes. I also installed a new striker block. This didn't help with the light strikes, but because it was slightly oversize I ended up with a much better "fit' than with the original part. Another part I ordered was a PM9 striker spring, so I tried it in the P380; shot a quick 30 rounds without a misfire, but the slide would move rearward as I pulled the trigger (heavier striker spring overcoming the recoil spring). I didn't like this, but the results had me thinking the spring might be the issue. I played around with P380 striker spring: stretching it, putting washers between it and the guide rod, I even cut some coils off.
I still had light strikes.
Finally it occurred to me that perhaps the cocking cam was the issue. I thought that it might not be lifting the striker block enough, possibly high enough that the CM9 striker spring could power the striker past it, but not enough for the 380 striker spring. Grasping at straws, I ordered a cocking cam and another 380 striker spring (curiously, this spring proved a little stronger than the first one I received).
http://i61.tinypic.com/2l92sgi.jpg
(L to R: broken 380 spring, cut down 380 spring, full length 380 spring, PM9 spring)
The ugly; The parts arrived and I proceeded to disassemble the frame. Removing the side plate, I immediately noticed that the bottom screw was not that tight...with the plate off, it looked like both screw holes had been drilled twice...not good.
http://i60.tinypic.com/23vj09t.jpg
I decided to deal with that later and continued with the dis-assembly. I made a small, non-marring taper punch from a bamboo chopstick and used this with an arbor press to remove the trigger axis pin (I hold the punch in place during this operation). The press is only needed to start the pin out, once it's past the retaining pin a brass rod can complete the job.
http://i60.tinypic.com/3136hxz.jpg
http://i59.tinypic.com/2rqkk60.jpg
http://i59.tinypic.com/mt2ja1.jpg
I used a dental pick to pry the cocking cam axis pin up enough to pull it out.
http://i58.tinypic.com/2ecma1k.jpg

...to be continued

[gb6491]

Houston we have a problem!
Comparing the cocking cams, there's a considerable difference in profile, but the new cam did have more "lift" on the striker block lobe.
http://i60.tinypic.com/21n4ion.jpg
The problem is that the lobe is not as wide as that on the old cam...well.... actually the bigger problem is that this results in the whole cam being not as wide as the old cam.
http://i61.tinypic.com/2z3z18z.jpg
http://i62.tinypic.com/14iizqq.jpg
Bummer..I planned to call Kahr about this the following day, but sitting there staring at the parts I decided to look through my accumulated washer stash. This search turned up some gold ...OK, so it's brass, but it works (precise fit on the axis pin)!. I like how this settled out as the cocking cam now has metal bearing surfaces on either side of it and is aligned with the striker block.
http://i58.tinypic.com/2ihbepu.jpg
http://i61.tinypic.com/2hr1sif.jpg
...to be continued

[gb6491]

On to the screw holes: the upper screw is not as bad as it looks because the secondary hole didn't affect where the screw bites into the frame. I did a little cosmetic work here with super glue. The bottom screw was a different story. The secondary hole intersected the wall of the primary screw hole. This is why the bottom screw didn't feel tight. I made a plug for the secondary hole from a plastic/nylon spot tie and glued it in place. After the glue set, I trimmed the plug down and used the screw to "thread" the plug. Time will tell, but I was able to repeatedly snug the side plate screws firmly in place.
http://i57.tinypic.com/2m2fbjm.jpg
http://i60.tinypic.com/dotjj4.jpg
http://i57.tinypic.com/149u6p.jpg

The happy ending?....with the new cam in place and everything back together, I've put about 125 rounds downrange without a single light strike:)
http://i61.tinypic.com/mm935s.jpg
Regards,
Greg

[kerby9mm]

That's impressive what you have done to make your p380 function correctly. From the diagnosis down to the obstacle impaired fix. You are great at fixing what I wound not even consider attempting. Everyone with a p380 problem should send their gun to you instead of Kahr. It would be fixed the 1st time.

[kwh]

Well done and with pictures told the whole story.

[SlowBurn]

In addition to awe inspiring expertise and ingenuity, there's also a mystery. Why was the new cocking cam so different?

I heard that a certain run of P380s made around 2010 had light strike and other problems. Serial numbers RB and early RC. I thought the issue was the frame but wonder if the new cam design is part of a change Kahr made in response?

[Bill K]

Wow! Very impressive. Where did you get all the knowledge and confidence to do all that work on your Kahr?

[RRP]

I wonder how many KahrTalk members have the mechanical aptitude, the troubleshooting skills, and the perseverance displayed by Greg in this thread?

So, the next time a newbie posts about their frustration with a new gun they expected would function correctly, out-of-the-box, I hope the Kahr disciples remember Greg's experience. Their frustration may be justified.

Well done, Greg!

[ReManG]

What kind of glue did you use in the frame when gluing the zip tie in place?

[muggsy]

Just out of curiosity I disassembled my P380 to see which cocking cam is in mine. The gun had the frame replaced by Kahr about six months ago. It has the new style of cocking cam. I guess we now know what to tell someone who is experiencing light strikes. Send your gun to Greg. :)

[TucsonMTB]

http://i57.tinypic.com/149u6p.jpg


http://i61.tinypic.com/mm935s.jpg

Nicely done, sir!

[gb6491]

Folks,
Thanks for all the comments, I very much appreciate you taking the time to do that:)

To answer a few questions

In addition to awe inspiring expertise and ingenuity, there's also a mystery. Why was the new cocking cam so different?

I heard that a certain run of P380s made around 2010 had light strike and other problems. Serial numbers RB and early RC. I thought the issue was the frame but wonder if the new cam design is part of a change Kahr made in response?

Just out of curiosity I disassembled my P380 to see which cocking cam is in mine. The gun had the frame replaced by Kahr about six months ago. It has the new style of cocking cam. I guess we now know what to tell someone who is experiencing light strikes. Send your gun to Greg. :)
This is an "RB" serial number range P380, thanks for bringing that up SlowBurn.
As muggsy has checked his P380 with a new frame (thanks for that!) and found the new style cocking cam, I suspect Kahr has tweaked the frames to add more polymer in that area.


Wow! Very impressive. Where did you get all the knowledge and confidence to do all that work on your Kahr?
I've a lot to learn, but I've always been a tinkerer, the rest I blame on the Marine Corps (noting your 542 Tigers patch, I imagine you can relate to that, Semper Fi Brother).


What kind of glue did you use in the frame when gluing the zip tie in place?
Super glue. It seems to hold it pretty well as I installed and removed the side plate quite a few times to test it (outside a parts failureI don't foresee taking it off again). There are probably some mechanical considerations as well: the shape of the plug helps keep it from turning, pressing the plate down while installing the screw prevents it from lifting, and there's pressure on it from the screw once it's installed.

Regards,
Greg

[marshal kane]

Ditto what everyone has said about your analysis and mechanical abilities. You make a helluva gunsmith! Thanks for all the neat pictures!

[Bawanna]

Greg is one incredibly smart cookie. Very mechanically talented. Definitely my #1 go to guy when I'm trying to figure something out.

If I took my gun down that far it would probably never look like a gun again and certainly never work properly.

My hats off to him as usual. Very well done.

[BEARDOG]

Excellent work Greg! Nice pics as well. I think you know this, but like Col B said above you are also my #1 go to source for intelligent and detailed info. When I start digging into an issue I always check to see if you have already dealt with it or something similar, and most times you have, and that saves me a lot of time in doing my own mods.

[josp]

It just so happens I have an extra set of PM9 sights lying around I could send to you or install on your slide if you want.

[SmokyT]

Great post, Greg! Thank you so much for sharing your experience and fix with us.
My P380 also had persistent FTFire (light strikes) problems, which I also figured (finally) was attributable to the cocking mechanism. But I did not want to disassemble the trigger and cocking mechanisms. So I used an old inner recoil spring from Kel-Tec P3AT to make a custom striker spring that is strong enough to strike primers of high quality defensive ammo but not strong enough to move the slide back as I pull the trigger.


I just tested this custom striker spring by shooting 81 rounds of Speer GDs that I normally carry without a single light primer strike. (Cost me over $100 to test the reliability of this little gun with my carry ammo!) I'll see if this new striker spring also works on cheeper range ammo by CCI and UMC...

[gb6491]

TucsonMTB, Nice to see you posting and thanks! Hope all is well with you and yours.

marshal kane, thanks:)

Bawanna and BEARDOG, I must say that I'm an admirer of the work you both do, so your comments are especially heart felt.

josp, that's an excellent offer. I haven't really considered swapping the sights out, but will PM you.

SmokyT, thank you for posting the info on your custom striker spring. That kind of input is very much appreciated!

Regards,
Greg

[berettabone]

:yo:

[Bobshouse]

Tagged so I can find this again!