What causes the cracks in the mags?

[Orphanedcowboy]

I have had 2 6rd "K420" mags crack at the rear upper portion. It doesn't seem to be an overwhelming problem from looking at the various forums.

On a side note, I called Kahr and they are sending replacements asap so that makes me happy.

[JFootin]

My opinion, and probably not worth 2 cents, is that the mag is riding a few mm too high and getting slammed by the bullet stripper on the bottom of the slide. That seems to me to be the only thing that could put that much of a hit on the mag. Maybe this is caused by an out of spec mag catch window on the mag. I think this could be eliminated if Kahr would redesign their mags to flush fit into shaped recesses on the bottom of the grip frame like Glocks and many other guns. The way they are now with the gap at the bottom, it is all up to the mag catch to determine the position of the mag in the gun. And the gap allows for the possibility of a mag being pushed up too far where damage can happen. JMHO. YMMV. :cool:

[Thunder71]

Squeezing them in a vice.

[OldLincoln]

Metal cracks because it is flexing. If the new mags also crack I would ask Kahr about the poly frame. Or as Thunder said.... if you do squeeze them, do it in the middle not close to the edges.

[jocko]

I go withg JFopotin analysis. alot have broken in less than one magazine load, not 9ndicative of weak steel. I don't buy the squeezing thing either as most all have broken without anything ever being done to them. I think tha tis also why kahr sometimes wants the entire gun back. It seems more prominent in the 45's for some reason. It takes alot of violent force to crack some of the magazines the way we hav eseen them. We will never know, for I don't see kahr saying aything about what is going on other than they will fix the issues..

[Tilos]

The mags become "work hardened" from the bending/forming process and crack in the corner, where the metal is stretched/coined the most.
They could be annealed and re-hardened for uniformity but this would add cost to the process.

I've never seen a cracked mag but ask those who have, was there any score marks on the inside of the corners that cracked.

Any tool marks inside could create a stress point for a crack to start.
I can tell from the finish that the mags are tumbled/shot peened on the outside to smooth the surface but have not looked inside of one too closely.

just guessin'
Tilos

[jocko]

imo IT IS NOT A MAG ISSUE. U sure don;t read about this mag thing in other gun makes, and certainly if it happens is is so so rare for other gun makers that it isn't even discussed as an issue. companies that make magazines for a living certanly know how to make magazines, so I aint buyin the mag thing.. Just sayin

[Orphanedcowboy]

I looked at the mags, and none, including the cracked ones are showing any evidence of the slide catching the mag. I looked at the 3 7 rdrs I just sold and the 4 6 rdrs I have. The ones that are cracked are packed up and on their way to Kahr now. I wished I would have broke them down and had a good close look at them. I did take a quick look at the interior prior to shipping and they looked to be finished just as well as the others.

[CJB]

Gonna mildly disagree with Jocko... its been a problem in the past for Colt, Randall, Metalform, IMI (Israel), Browning, MecGar, probably others. I've got Colt and Randall magazines with cracks that I still use for range use... since they still work "ok".

Just my 2 cents - magazine steel is fairly brittle stuff, and they've put some nasty folds in it. That being given... now consider forming dies and the metal itself. Its always a juggle fest when dealing with manufacturing an item where the incoming raw material (the steel) may not be exactly the same from run to run. Then you got slightly dissimilar steels and the heat treatment (and or pre-stress or post-stress relief).

Remember the OLD Colt magazines where only the tops were heat treated? You could see the flame treatment they got... maybe they had something there.

Bottom line - occasionally, all variables in mags, and pistols alike, you get a mag that cracks, maybe a whole run of 'em that is prone to cracking. Wish it wasn't so, but its not totally new territory to cover as far as problems go.

[jocko]

I did not know that, one seems to not read about those issues nearly like kahr has with them. I still feel it is a gun related thing more than the magazine, but I can't prove otherwise. We tend to look at the end result of an issue, (like cracked magazines) and always blame the magazines. Lately kahr has ask for some of the guns to be returned with the split magazines. That to me was some sore of indicator that it could be gun related. I think it was wyn who had alot of split magazines and correct me if I am wrong but I think it took an entire new gun to get him right.

We have seen some magazines split in the first usage. I can say that my new P380 when I bought it, the one magazine split in the first half dozen loads. It has never given an issue since with the magazines...

[Tilos]

CJB:
To your point and as I mentioned before, a minor scratch on the tooling that's used to bend/form the shape could transfer to many, many mags in a high speed manufacturing process.

Once a large amount of mags are accepted from a vendor, and later found to have some defects in use, the only choice would be to have a recall or deal with it on an individual bases by replacement.

It seems Kahr has decided to replace any that prove defective in use.

I'll ask anyone who have delt with this issue, has Kahr asked for the GUN to be returned or just the mag??

Again, a stress point could be so small as being undetected with the naked eye.

Orphanedcowboy: Thanks for posting.

Tilos

[muggsy]

The mags become "work hardened" from the bending/forming process and crack in the corner, where the metal is stretched/coined the most.
They could be annealed and re-hardened for uniformity but this would add cost to the process.

I've never seen a cracked mag but ask those who have, was there any score marks on the inside of the corners that cracked.

Any tool marks inside could create a stress point for a crack to start.
I can tell from the finish that the mags are tumbled/shot peened on the outside to smooth the surface but have not looked inside of one too closely.

just guessin'
Tilos

Tilos, as a machinist I agree with your analysis completely.

[michpatriot]

We really need pics.

[Orphanedcowboy]

It seems Kahr has decided to replace any that prove defective in use.

I'll ask anyone who have dealt with this issue, has Kahr asked for the GUN to be returned or just the mag??

Tilos

They only asked for the magazines back, even shipped two prior to receiving them as well.


We really need pics.

That was an afterthought once they were already in the mail, sorry.

[CJB]

I did not know that......
..... kahr has ask for some of the guns to be returned with the split magazines. That to me was some sore of indicator that it could be gun related. I think it was wyn who had alot of split magazines and correct me if I am wrong but I think it took an entire new gun to get him right.

I'm not sayin' that it can't be the gun, I'm just sayin' that cracked magazines are nothing new under the sun. Could also be that Kahr wanted to rule out the gun, or... they knew something they're not saying, or both.:cool:

Its ok Jocko... I think we're really on the same page... I'm just giving some horizontal leeway to the whole discussion :)

[CJB]

more thoughts....after more reading here....

Tooling, work hardening, variable metallurgy, or pistol variables.

E. All of the above.

I've done my share of manufacturing oversight. Its a wild ride to keep things right. No matter how simple you make it, somebody is gonna find a way to screw it up.

[Orphanedcowboy]

Well the replacement mag arrived today. It is slightly different than the originals.

[jocko]

in what way??> a photo would be very nice..

[jocko]

CJB:
To your point and as I mentioned before, a minor scratch on the tooling that's used to bend/form the shape could transfer to many, many mags in a high speed manufacturing process.

Once a large amount of mags are accepted from a vendor, and later found to have some defects in use, the only choice would be to have a recall or deal with it on an individual bases by replacement.

It seems Kahr has decided to replace any that prove defective in use.

I'll ask anyone who have delt with this issue, has Kahr asked for the GUN to be returned or just the mag??

Again, a stress point could be so small as being undetected with the naked eye.

Orphanedcowboy: Thanks for posting.

Tilos

magazaines, they are not gonna recall them, evenif they know some are bad, as "wheredo they start". They will replace bad magazines as long as they are sent back, I have no doubt about that. They itis not abuse but a defect of some some sort. I don't know who makes kahrs mags but they are stainless, they don't seem cheap in qality but yet something is causing this splitting and it is neve rin the welds. Companies that makes magazines normaly know how to make good magazines, that is their job, we have seen badmagazinesfor at least over 2 years, so I just ain't buying "poor" steel or bad batch. Just assiming here maybe more than I should to, but I still tend to think it is more gun related and I can't prove that at all..

[Orphanedcowboy]

Pictures:

https://lh6.googleusercontent.com/-ACIKayVhaS4/T1YgDRgWzNI/AAAAAAAADIo/Ifljrcuh5GI/s512/DSCI0028.JPG

https://lh3.googleusercontent.com/-_qD6FDzuDKw/T1YgFAzgVoI/AAAAAAAADI4/mrpmFvaDHIg/s512/DSCI0029.JPG

https://lh5.googleusercontent.com/-nHaPXCVx7ys/T1YgBy9r5iI/AAAAAAAADIg/IGU1hqX-PWg/s720/DSCI0031.JPG

https://lh5.googleusercontent.com/-4mULmLPhShM/T1YgDk8kGdI/AAAAAAAADIw/u1eDKgKBd1Q/s720/DSCI0032.JPG

Changes I noticed:

They moved the engraving up the side

The cut at the rear is larger

The radius on the back corners is bigger(not as tight where it is formed and also cracks)

The round count windows are actually lined up now

The edges of the lips are smoother, more polished feeling

The magazine it self feels grainy, like it could use a little longer in the tumbler

I also noticed the first round, last round loaded, the rim sets in the groove under the rim of the second round on both mags and no matter how hard I tried I cannot get it to seat flush with the back of the mag. This pistol has been flawless with every round fired though so it doesn't seem to bother the pistol as much a it bothers me.......

[Tilos]

Thanks for posting the pics

What I noticed right away, is the different number of round count holes (5-6).
I real visual que to ID "old and new", for us and Kahr.

In the rear view, the new mag seems smoother where the rear cut out transitions into the lips, where as the old looks pinched on the left, in the same area.

Me thinks Kahr as depleted their "last batch" of mags and now have/ship something better.
Tilos

[Orphanedcowboy]

Bought a couple more "K420" mags from Midway and they are the new style as well:

https://lh6.googleusercontent.com/-4n2c3euHNMk/T1fTS4_bhII/AAAAAAAADKM/P262Rhxb7Sc/s512/DSCI0049.JPG

[JimC]

It seems Kahr has decided to replace any that prove defective in use.

I'll ask anyone who have delt with this issue, has Kahr asked for the GUN to be returned or just the mag??

Again, a stress point could be so small as being undetected with the naked eye.

Orphanedcowboy: Thanks for posting.

Tilos

I'm a little late to respond but after reading this thread a couple of times, I decided that I would.

Yes, I had two mags split in the usual fold area on day one using my PM9.

Yes, Kahr paid the return shipping of my PM9 and the split mags. They insisted on having the PM9 returned and would not just replace the mags even if I returned the damaged mags first.

They found nothing wrong with the gun itself.

Out of 5 mags used that day, the two split after 425 rds. using all 5 mags.

The first mag split after firing approx. 256 rds. The second after 385 rds.

Both mags had far less than those numbers but they were in that initial round count.

Thankfully, I have not experienced any further mag failures with my PM9 since but, rest be assured, it's always on my mind.

When I examinded the mags after the splitting, there was no visible indication near the top of the split that there had been any abnormal contact between the slide and the mag. :confused:

These are the mags in question.

http://img.photobucket.com/albums/v226/KobraCarry/Kahr%20PM9/IMG_2447_680x510.jpg
http://img.photobucket.com/albums/v226/KobraCarry/Kahr%20PM9/IMG_2446_680x510.jpg

This is the report from the Kahr Technical Service Work Sheet

Problem Reported:
SPLITTING MAGAZINES, 2 MAGS

Action Taken:
POLISHED BARREL. REPLACED MAGS. LUBED TEST FIRED GOOD.

I believe that IF they had found anything wrong with the pistol that caused the problem, they would have indicated further repair.

IMO, what they did was absolutely nothing but replace the mags. It could be very possible that the people at Kahr just can't figure it out or they don't want to admit that they have a mag problem.

What does all of this say?

IMO, nothing at all except, a guy (me) buys a NIB pistol from his LGS, takes it to the range for the initial firing and has the problems indicated above, the mfg. of the pistol takes marginal steps to correct the problem and they hope they don't hear from the customer again.

[Thunder71]

...Or that the mags were at fault so they replaced them for you.

Sent using Tapatalk on Android

[skiflydive]

...Or that they wanted to have an opportunity to test/diagnose your pistol/mag SYSTEM to make sure there was nothing pistol related causing the problem. Thanks for sending the pistol in with the mags so they could see if there's something wrong with our guns that needs to be addressed.

[JimC]

...Or that the mags were at fault so they replaced them for you.

Sent using Tapatalk on Android

That is of course another way of looking at the problem. But, the obvious is...there is a problem.

I'm thankful that my mags were replaced and Kahr found nothing out of spec with my PM9 and there have been no further issue(s). ;)

[air8]

I hope my stock CW9 mag is ok. Today I'm taking 300-400 rounds for it, and 300-400 for my XDM9.I have the stock 7 round mag plus two 8 round mags I got from cheaper than dirt .com.

The two 8 round mags look just like the pics orphanedcowboy posted. Raised markings, different feel on the outside, different geometry at the described places.

I will be finding out here in a little bit. Headed to the range today. Yipeee!!!

[Tilos]

JimC:
Thanks for posting the pics

[air8]

Good news. No problems with cracking here. I put the CW9 through it's paces today. Shot 400+ rounds through it today. Only issues were the hollow points hanging up when riding the slide closed. Not that that is an issue. I always overhand power stroke or use the slide release, so I don't consider it an issue.

[2firfun50]

Pictures:

https://lh6.googleusercontent.com/-ACIKayVhaS4/T1YgDRgWzNI/AAAAAAAADIo/Ifljrcuh5GI/s512/DSCI0028.JPG

https://lh3.googleusercontent.com/-_qD6FDzuDKw/T1YgFAzgVoI/AAAAAAAADI4/mrpmFvaDHIg/s512/DSCI0029.JPG

https://lh5.googleusercontent.com/-nHaPXCVx7ys/T1YgBy9r5iI/AAAAAAAADIg/IGU1hqX-PWg/s720/DSCI0031.JPG

https://lh5.googleusercontent.com/-4mULmLPhShM/T1YgDk8kGdI/AAAAAAAADIw/u1eDKgKBd1Q/s720/DSCI0032.JPG

Changes I noticed:

They moved the engraving up the side

The cut at the rear is larger

The radius on the back corners is bigger(not as tight where it is formed and also cracks)

The round count windows are actually lined up now

The edges of the lips are smoother, more polished feeling

The magazine it self feels grainy, like it could use a little longer in the tumbler

I also noticed the first round, last round loaded, the rim sets in the groove under the rim of the second round on both mags and no matter how hard I tried I cannot get it to seat flush with the back of the mag. This pistol has been flawless with every round fired though so it doesn't seem to bother the pistol as much a it bothers me.......

New to the forum and to Kahr. My new CW45 cracked the mag in less than 50 and it is the style of the mag on the right. Looks just like it, 5 holes and all.

[jocko]

might just be me but IMO there asre bad mags still out there but I have noticed in the past couple of months that this mag thing has died down alot and when we have read it is not a new gun out of box mag issues. So lets hope this is getting behind us. We still have P380 giving some issues but again in the past few months the reports have been vbery posiitive compared to what it used to bej. Just sayin