Kahr CW40 failure to feed

aparootsa · October 25, 2024, 07:15 PM

I have a CW40 that has been very reliable for me since 2013, over roughly 1500 rounds.

Within the last 50 rounds or so, it has started failing to strip the round out of the magazine. This most often happens on the first round of the mag, but has happened on others as well. Up until now, it has fed flawlessly (slingshot loading or slide stop), so I'm at a loss.

I initially thought the mag wasn't seating fully, so I gave it a firm slap, and often that works to get it to chamber the round. If I give a nudge on the back of the slide, it chambers and fires just fine.

My initial thought was that the recoil spring needs replacing (and I have a new one on the way), but as I sat down to figure out how many rounds I've fed it, this seems like barely enough to break it in. Can that really be it? I supposed I'll have my answer when I put the new spring in, but thought I might get an answer sooner from y'all.

Dfariswheel · October 25, 2024, 07:21 PM

Almost certainly the recoil spring is due to be replaced.
These mini-guns are very hard on recoil springs.

Kahr has different replacement recommendations for the various models, but 1,000 rounds for the "full size" models seems to be right.
Surprisingly they also recommend recoil spring replacement every two years.

They also recommend a deep cleaning and inspection, and possibly replacing the other springs.
You can contact Kahr and ask and they'll tell what should be done and when.

Paul105 · October 25, 2024, 08:30 PM

Thoroughly clean and re lube using following directions:
.

.
Replace recoil spring and magazine
.
If that doesn't work, return to factory

Paul

FITASC · October 25, 2024, 08:52 PM

The Kahr forum ha great tips as well; when I had my CM9, I picked up a lot of good tips there

Mosin44az · October 26, 2024, 03:13 AM

Paul105’s post proves why the Kahr brand never really caught on.

No defensive pistol should require that level of maintenance. Ridiculous.

**JohnKSa** · October 26, 2024, 03:28 AM

Quote:

Almost certainly the recoil spring is due to be replaced.
These mini-guns are very hard on recoil springs.

Yup.

Small, light gun in a relatively heavy chambering. Expect very low recoil spring life.

5whiskey · October 26, 2024, 08:20 PM

Quote:

Paul105’s post proves why the Kahr brand never really caught on.

No defensive pistol should require that level of maintenance. Ridiculous.

Personally, I have a CW9 that I probably have 4k-5k rounds through. I've never replaced any spring, and I've never even seen that lube chart shown here (though admittedly, those are points that I lube on most or all pistols). What is it that you feel is inappropriate to lube? Some of these coincide with Glocks recommended lube plan (rails, outside of the barrel, sear engagement). The only "extra" steps (compared to a Glock) are the guide rod, slide stop, the firing pin block (admittedly I've never placed any lube on any firing pin block, including my Khar, and have never had a failire), and the slide stop channel in barrel assembly. Compared to many other pistols with a separate guide rod and through pin slide stop, the only extra lube recommendation i see for the Khar is the firing pin block.

OP does it do this with both magazines by chance? In addition to the recoil spring, the magazine springs could be getting weak and the slide outruns the mag spring. Just am thought.

Admittedly, these small pistols struggled more with reliability when chambered in .40 and .45 than with 9mm.

**JohnKSa** · October 26, 2024, 10:41 PM

Quote:

Admittedly, these small pistols struggled more with reliability when chambered in .40 and .45 than with 9mm.

Yup. I've had good luck with the CW9 and P9, but I wouldn't have that size/weight gun in a heavier chambering.

Mosin44az · October 27, 2024, 01:30 AM

The original K9 geometry in 9mm seems to be the most reliable. My smaller 9mm Kahrs (PM9, CM 9) were finicky at best, and my P380 simply abysmal.

it is a High Maintenance gun at best, and the chart brought back these memories.The main pistols today don’t require this.

Super Sneaky Steve · October 27, 2024, 01:36 PM

1500 rounds is a very good run. My PM45 needs a new recoil spring every 500 rounds.

tangolima · October 27, 2024, 04:45 PM

Is the spring regular round wire or flat? Flat will do better.

For the op's feeding issue, exactly what happened when it misfed? Did the round missed the chamber? Was the ammo exactly the same as before? It could still be causes other than the spring.

-TL

Sent from my SM-N960U using Tapatalk

**JohnKSa** · October 27, 2024, 05:13 PM

Failed to strip the round from the mag--most often the top round.

HighValleyRanch · October 27, 2024, 06:07 PM

Does this happen with different magazines? Have you tried loading with one less round in the mag? Could be a magazine problem as well.

tangolima · October 27, 2024, 08:00 PM

Quote:

Originally Posted by JohnKSa

Failed to strip the round from the mag--most often the top round.

Yeah but did the bullet make its way into the chamber? It could be 3 point bind that caused by long COAL.

-TL

Sent from my SM-N960U using Tapatalk

HighValleyRanch · October 27, 2024, 08:33 PM

I found that my Kahr P45 had a really tight chamber causing feeding problems. So I had the freebore throated and this really helped any feeding problems I had due to long COAL.
But I still have to keep the overall length short because of the tight tolerances in the slide and ejection port. A type 3 malfunction can be hard to clear if the COAL is too long.
I have to do the plunk test to make sure that the particular ammo will work.
If I do all that, it feeds very reliably.
The feed ramp is pretty steep as well.

But my PM9 is stock and runs flawlessly.

TheFlash · October 29, 2024, 10:00 AM

As was mentioned in one post above, I would check the magazines and the magazine springs. If those are also original and had many 'load/unload' cycles, then pick up a couple extra OEM magazines and try those. (Or if there are Kahr mag spring & follower replacement kits?)

FITASC · October 30, 2024, 05:51 PM

Kahr had issues previously with the mag springs being installed backwards, resulting in misfeeds; that's an easy check to see if it solves any misfeed issues

**4V50 Gary** · October 30, 2024, 11:06 PM

Clean and lubricate is the first step.

Using factory magazines, try different types of ammunition. Find out what works best.

Dfariswheel · October 31, 2024, 08:22 PM

I got some interesting info from Kahr recently....
They say that the guys in the shop pre-break in new recoil springs by slipping the spring on a screwdriver shaft and pressing the spring against the edge of a bench to fully compress it 4 or 5 times.

Also, as above always be certain the spring is on the guide correctly. The larger open end faces forward.

aparootsa · November 4, 2024, 10:45 PM

Well, the new recoil spring arrived and I got it swapped out. No change. Haven't followed the lube instructions; I'll do that probably when I get back from hunting in a couple of weeks. In the meantime, here's a picture of the old and new springs (looks like a good call to replace, just based on fatigue). Might get a new magazine spring too, but the lube first. I'm also attaching a photo of the failure; this is after racking the slide. The cartridge is brought just a tiny bit forward until the nose engages the feed ramp, and then the slide stops.

October 25, 2024, 07:15 PM	#1
aparootsa Member Join Date: March 29, 2009 Posts: 74	Kahr CW40 failure to feed I have a CW40 that has been very reliable for me since 2013, over roughly 1500 rounds. Within the last 50 rounds or so, it has started failing to strip the round out of the magazine. This most often happens on the first round of the mag, but has happened on others as well. Up until now, it has fed flawlessly (slingshot loading or slide stop), so I'm at a loss. I initially thought the mag wasn't seating fully, so I gave it a firm slap, and often that works to get it to chamber the round. If I give a nudge on the back of the slide, it chambers and fires just fine. My initial thought was that the recoil spring needs replacing (and I have a new one on the way), but as I sat down to figure out how many rounds I've fed it, this seems like barely enough to break it in. Can that really be it? I supposed I'll have my answer when I put the new spring in, but thought I might get an answer sooner from y'all.

October 25, 2024, 08:52 PM	#4
FITASC Senior Member Join Date: December 6, 2014 Posts: 6,645	The Kahr forum ha great tips as well; when I had my CM9, I picked up a lot of good tips there __________________ "I believe that people have a right to decide their own destinies; people own themselves. I also believe that, in a democracy, government exists because (and only so long as) individual citizens give it a 'temporary license to exist'—in exchange for a promise that it will behave itself. In a democracy, you own the government—it doesn't own you."- Frank Zappa

October 27, 2024, 05:13 PM	#12
JohnKSa Staff Join Date: February 12, 2001 Location: DFW Area Posts: 25,564	Failed to strip the round from the mag--most often the top round. __________________ Do you know about the TEXAS State Rifle Association?

October 27, 2024, 06:07 PM	#13
HighValleyRanch Senior Member Join Date: July 15, 2005 Posts: 4,133	Does this happen with different magazines? Have you tried loading with one less round in the mag? Could be a magazine problem as well. __________________ From the sweet grass to the slaughter house; From birth until death; We travel between these two eternities........from 'Broken Trail"

October 27, 2024, 08:33 PM	#15
HighValleyRanch Senior Member Join Date: July 15, 2005 Posts: 4,133	I found that my Kahr P45 had a really tight chamber causing feeding problems. So I had the freebore throated and this really helped any feeding problems I had due to long COAL. But I still have to keep the overall length short because of the tight tolerances in the slide and ejection port. A type 3 malfunction can be hard to clear if the COAL is too long. I have to do the plunk test to make sure that the particular ammo will work. If I do all that, it feeds very reliably. The feed ramp is pretty steep as well. But my PM9 is stock and runs flawlessly. __________________ From the sweet grass to the slaughter house; From birth until death; We travel between these two eternities........from 'Broken Trail"

October 25, 2024, 07:21 PM	#2
Dfariswheel Senior Member Join Date: May 4, 2001 Posts: 7,559	Almost certainly the recoil spring is due to be replaced. These mini-guns are very hard on recoil springs. Kahr has different replacement recommendations for the various models, but 1,000 rounds for the "full size" models seems to be right. Surprisingly they also recommend recoil spring replacement every two years. They also recommend a deep cleaning and inspection, and possibly replacing the other springs. You can contact Kahr and ask and they'll tell what should be done and when.

October 25, 2024, 08:30 PM	#3
Paul105 Senior Member Join Date: March 26, 2007 Location: Montana Posts: 347	Thoroughly clean and re lube using following directions: . . Replace recoil spring and magazine . If that doesn't work, return to factory Paul

October 26, 2024, 03:13 AM	#5
Mosin44az Senior Member Join Date: January 15, 2006 Posts: 2,626	Paul105’s post proves why the Kahr brand never really caught on. No defensive pistol should require that level of maintenance. Ridiculous.

October 27, 2024, 01:30 AM	#9
Mosin44az Senior Member Join Date: January 15, 2006 Posts: 2,626	The original K9 geometry in 9mm seems to be the most reliable. My smaller 9mm Kahrs (PM9, CM 9) were finicky at best, and my P380 simply abysmal. it is a High Maintenance gun at best, and the chart brought back these memories.The main pistols today don’t require this.

October 27, 2024, 01:36 PM	#10
Super Sneaky Steve Senior Member Join Date: August 9, 2011 Posts: 1,326	1500 rounds is a very good run. My PM45 needs a new recoil spring every 500 rounds.

October 27, 2024, 04:45 PM	#11
tangolima Senior Member Join Date: September 28, 2013 Posts: 5,167	Is the spring regular round wire or flat? Flat will do better. For the op's feeding issue, exactly what happened when it misfed? Did the round missed the chamber? Was the ammo exactly the same as before? It could still be causes other than the spring. -TL Sent from my SM-N960U using Tapatalk

October 29, 2024, 10:00 AM	#16
TheFlash Senior Member Join Date: October 9, 2012 Location: San Jose, CA Posts: 108	As was mentioned in one post above, I would check the magazines and the magazine springs. If those are also original and had many 'load/unload' cycles, then pick up a couple extra OEM magazines and try those. (Or if there are Kahr mag spring & follower replacement kits?)

October 30, 2024, 05:51 PM	#17
FITASC Senior Member Join Date: December 6, 2014 Posts: 6,645	Kahr had issues previously with the mag springs being installed backwards, resulting in misfeeds; that's an easy check to see if it solves any misfeed issues __________________ "I believe that people have a right to decide their own destinies; people own themselves. I also believe that, in a democracy, government exists because (and only so long as) individual citizens give it a 'temporary license to exist'—in exchange for a promise that it will behave itself. In a democracy, you own the government—it doesn't own you."- Frank Zappa

October 30, 2024, 11:06 PM	#18
4V50 Gary Staff Join Date: November 2, 1998 Location: Colorado Posts: 22,298	Clean and lubricate is the first step. Using factory magazines, try different types of ammunition. Find out what works best. __________________ Vigilantibus et non dormientibus jura subveniunt. *Molon Labe!*

October 31, 2024, 08:22 PM	#19
Dfariswheel Senior Member Join Date: May 4, 2001 Posts: 7,559	I got some interesting info from Kahr recently.... They say that the guys in the shop pre-break in new recoil springs by slipping the spring on a screwdriver shaft and pressing the spring against the edge of a bench to fully compress it 4 or 5 times. Also, as above always be certain the spring is on the guide correctly. The larger open end faces forward.

November 4, 2024, 10:45 PM	#20
aparootsa Member Join Date: March 29, 2009 Posts: 74	Update and some pics Well, the new recoil spring arrived and I got it swapped out. No change. Haven't followed the lube instructions; I'll do that probably when I get back from hunting in a couple of weeks. In the meantime, here's a picture of the old and new springs (looks like a good call to replace, just based on fatigue). Might get a new magazine spring too, but the lube first. I'm also attaching a photo of the failure; this is after racking the slide. The cartridge is brought just a tiny bit forward until the nose engages the feed ramp, and then the slide stops.