Kahr Magazine Design - Why?


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holdencm9
May 16, 2012, 06:26 PM
So many of you are probably familiar with the Kahr Magazines and the infamous nosedive issue. (If not, a quick google search will reveal to you many threads of complaints, fixes, mods, etc. Basically as you push in more rounds, they start to fan out more and more, so the second-to-last round is essentially pointed downward at like a 30-degree angle. This can cause jams during shooting or chambering the first round. )

The follower has some wiggle room in the magazine, as well as a different angle at the front lip that creates a ridge and allows this. My question is why? Why don't they just make the follower fit snugger, with a flat monoslope surface (which is what most people create when they sand down their followers). Is there something I am missing?

Luckily I haven't had any issues with it during shooting my CW9, but I did notice that if I try cycle manually and ride the slide forward to chamber a round, it gets hung up, so I am tempted to do the sanding of the follower. Yeah yeah, if it ain't broke don't fix it, but I like the idea of being able to cycle a round manually as fast or as slow as I want.

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9mmepiphany
May 16, 2012, 06:48 PM
You're looking/seeing a couple of only coincidentally related issues and drawing a conclusion as if they are the same.

The angle that the cartridges lay at in the magazine is a product of the taper of the case...the top round straightens as it reaches the lips which guide its feed angle into the chamber. The .40S&W and .45ACP have much straighter cases and lay more parallel to each other. Examples of how other designers have handled this are the banana magazines of the AK and the sloped magazine of the Enfield #4.

Manually cycling from the magazine has to do with the travel and velocity need to overcome the tension in the straight magazine. The manual specifically advises against this as most people compromise the speed/force needed by not providing a stable platform for the slide mass to work against...sort of the reverse of limp wristing against recoil. Due to its small proportions, the Kahr functions in a small operational window. It is optimized to operate when the slide is cycled by the recoil of the previous cartridge

You shouldn't be riding the slide down to chamber a round in anyway. That is the universal first step to a jam on most platforms and marks you as a novice to semiautomatic pistols

19-3Ben
May 16, 2012, 08:09 PM
so I am tempted to do the sanding of the follower.

Seriously think about what you are doing and really consider the ups and downs of that course of action before removing metal and altering the characteristics of any gun that will be used for self defense.

matrem
May 16, 2012, 08:10 PM
My limited experience has been very good with the 6 round mags in a CM9.
The one 7 round I've tried seems to have some serious "nose dive" issues.
From what I've gathered, that's quite common with Kahr.

kokapelli
May 16, 2012, 08:12 PM
I have two Kahr pistols and have never had a problem with the magazines.

The Lone Haranguer
May 16, 2012, 08:52 PM
Basically as you push in more rounds, they start to fan out more and more, so the second-to-last round is essentially pointed downward at like a 30-degree angle. Yes, they do that, but I assume that is what the offset, deep feed ramp is for. What I did have a beef with was not holding the top round very securely, allowing it to "walk" forward and interfere with fast reloading. A snugly fitting magazine pouch, preferably sized to fit it as opposed to a "generic" or "universal" sizing, would mitigate against it somewhat.
This can cause jams during shooting or chambering the first round.
That, I did not have any trouble with.

rhinoh
May 16, 2012, 09:13 PM
I agree riding the slide home is not conducive to correct operation. I also agree the top round in my CM9 mags isn't held real well. They pop out all the time on the spare mag in my other front pocket opposite the weapon.
All that said my 2 CM9's have been flawless! Never a feed issue at all.

matrem
May 16, 2012, 09:25 PM
All that said my 2 CM9's have been flawless!
You Sir, are either a very lucky guy, I'm an unlucky one, or you don't shoot much.

9mmepiphany
May 16, 2012, 10:30 PM
Yes, they do that, but I assume that is what the offset, deep feed ramp is for. What I did have a beef with was not holding the top round very securely, allowing it to "walk" forward and interfere with fast reloading.
The off-set feedramp (it was granted a patent) is to allow the barrel to sit lower in relation to the magazine...making both the boreline lower and the gun shorter overall as the slide is now shorter.

The second next round up walking is pretty common among single stack magazines. My Sig 220, 225, 1911 and S&W 39 all do this

holdencm9
May 16, 2012, 11:01 PM
I think he was saying that the top round in a spare mag, if left in a pocket or something, will eventually walk its way out of the magazine completely.

I did not say I would ride the slide forward in a failure drill or anything, but I mean, in a Kahr you have to sort of slingshot" the slide forward. For some people, using the slide release doesn't even do the trick. The slide needs that extra 1/4" of momentum to chamber the round. Not that I have had problems under normal use, but what if I want to chamber a round quietly? :)

Seriously think about what you are doing and really consider the ups and downs of that course of action before removing metal and altering the characteristics of any gun that will be used for self defense.

I am, hence the thread. Of course any mods would be thoroughly tested before I carried it. (PS the follower is the only thing that would be modded and it is plastic)

holdencm9
May 16, 2012, 11:15 PM
The angle that the cartridges lay at in the magazine is a product of the taper of the case...the top round straightens as it reaches the lips which guide its feed angle into the chamber. The .40S&W and .45ACP have much straighter cases and lay more parallel to each other. Examples of how other designers have handled this are the banana magazines of the AK and the sloped magazine of the Enfield #4.

Maybe, but it is exaggerated in the Kahr. Furthermore, the first 4 rounds all go in parallel to one another. It is only the last couple that the fanning is perceived.

Manually cycling from the magazine has to do with the travel and velocity need to overcome the tension in the straight magazine. The manual specifically advises against this as most people compromise the speed/force needed by not providing a stable platform for the slide mass to work against...sort of the reverse of limp wristing against recoil. Due to its small proportions, the Kahr functions in a small operational window. It is optimized to operate when the slide is cycled by the recoil of the previous cartridge

I understand that, but I guess that is what I was wondering about....if people are sanding their followers and getting great results, the gun still operates fine AND they can slowly cycle rounds in and out, why not?

You shouldn't be riding the slide down to chamber a round in anyway. That is the universal first step to a jam on most platforms and marks you as a novice to semiautomatic pistols

I disagree. I can do it in lots of semi autos. And I don't think you were trying to be condescending but that sentence sort of reads that way. I am no expert but not a newbie either.

9mmepiphany
May 16, 2012, 11:57 PM
Not that I have had problems under normal use, but what if I want to chamber a round quietly? :)
I do have a condescending response for this, but rather than post that, I'll ask the obvious question...

When would you want to chamber a round quietly?

If there was a perception of possible danger...to the point you felt that you needed to draw a gun...why would you not already have a round already chambered?

And I don't think you were trying to be condescending but that sentence sort of reads that way. I am no expert but not a newbie either.
You are correct, I did not mean it to be condescending. I meant it as an advisory to folks reading it who might think is was a part of a correct manual of arms for a semiautomatic pistol...it is completely different than a chamber check, which is slowly retracting and then closing the slide after the round has already been chambered

Riding a slide down to chamber a round is equivalent to swinging a cylinder closed on a revolver with a flick of the wrist..they are products of a movie or television director's desire to heighten drama

holdencm9
May 17, 2012, 01:16 AM
Maybe the wife is taking a nap? Joking anyways.

The whole point was why it is designed with the ridge on the follower, that allows the rounds to fan out the way they do. It can't just be the taper of the case. If you took 7 rounds and pushed them snug up to each other they would want to all point inward. In the Kahr mags, they fan OUT. I just don't get why they'd put that ridge there on top of the follower. It seems the production would be cheaper to just leave it flat, and people who mod it that way seem to have good success.

BamAlmighty
May 17, 2012, 01:58 AM
Hundreds of rounds through my CW9 and CM9, no problems here.

And there are quite a few of us with nothing but raves for the CM/PM9... http://www.thehighroad.org/showthread.php?t=658899

JDGray
May 17, 2012, 06:21 AM
Riding the slide is not tacticool, hence, dont do it!! :rolleyes:I for one, shoot my carry gun alot, and cant affort a steady supply of Golddot carry ammo... If you rechamber your carry ammo over and over, you could cause a very dangerous setback condition, so to lessen the chance of that happening, I will ride the slide recambering my carry ammo after a range session. Nothing Hollywood about that. Be sure to do a press check however, to be sure the case head is behind the extractor claw.

The only Kahr mag issues I have, is no slide lock on empty about 50% of the time.

Shipwreck
May 17, 2012, 08:47 AM
I had a PM9 for a couple of years, and just sold it two weeks ago after buying the Shield.

That being said, in 9mm, it was the only semi auto I ever owned where I periodically had to throw away a round due to rechambering. This is a known issue in other calipers, but not so much in 9mm.

I reoil the rails 1x a week, as the oil evaporates in very hot weather. And admittedly, this was a pain with the kahr.

(had to edit it - I HATE auto complete on the ipad - sorry for the typos)

kim breed
May 17, 2012, 09:36 AM
Carry my CW9 almost every day and have put thousands of rounds thru it. gun runs great every time.

Dean1818
May 17, 2012, 09:58 AM
I sanded down the follower to keep less of an angle on bullet 1 and 2 in the mag. This allows me to rack the slide like my other pistols.

(i dont like using the slide stop to chamber a round)

I also did the slight vise "squeeze" on the top of my mag, and it now drops free like my other pistols.

I agree with the OP...... The mags could stand to be redesigned.

With the mods my pistol is 100 reliable....... I wish kahr would just ship them that way.

The CM9 is an accurate, very reliable, truly pocketable pistol that has a smooth, but very long
trigger and to me is the best size to weight ratio pistol in 9mm that is available.

When i need to pocket carry, the CM9 is the one I choose

Even if it isnt perfect


Also........ Gun grease on the rails is always the best solution..... On any pistol

holdencm9
May 17, 2012, 10:26 AM
JDGray, good point. I can't afford constantly burning through my Gold Dots either, so usually before going to the range it is drop mag and eject cartridge, only to rechamber that same cartridge after the range visit. I just don't like how un-smooth it is, and if it can damage a cartridge that is especially bad. You could rotate the rounds to be chambered but that is not really a solution.

Dean1818, glad to hear another person had success with the mod. I think maybe since I have 4 mags I'll just experiment with one and test it out. I agree Kahr magazine are the weakest aspect. Great guns, poor magazines.

Again, not knocking the gun. I love my CW9. Just trying to look at the magazine from a designer's perspective and ask why? And see if there is any reason not to do the sanding-down mod, and so far I haven't found any.

340PD
May 17, 2012, 11:27 AM
I also spent 30 seconds on the plastic follower with 400 grit sandpaper wrapped around a dowel to change the angle just slightly. This permits me to chamber a round operating the slide slowly rather than using the slide stop. Working as a part time RSO at cleanup I find all sorts of live rounds over the firing line. ALL of these, if factory rounds, go into my Kahr. They ALL have fed with no issues. If they did not fire it was a factory defect. The gun also fires all my handloads. I just barely changed the shape of my follower. Much less than the pictures show and it works perfectly. No gun is perfect, but my personal PM9 is my carry gun of choice.


http://kahrtalk.com/showthread.php?t=6943&page=2

hardluk1
May 17, 2012, 11:52 AM
I have a cm9 and cw9 and both I will hand cycle the slide slowly just fine and have yet to have a noise dive under any condition. I have around 2200 rounds fired. Not much compared to some owners. But both run fine. I do see the difference in the scond round in the mag when loaded but just have not had to deal with any problems. I use a 8 round mag for back up and keep it upside down in the knife pocket on my jeans for 2 years now and never lost a bullet yet from it . Also at the range I will use the cw9 mag to run out the hp ammo and then cycle all three during range time. Maybe lucky , don't know . Just not had to work thru and problems at all from round 1.

LongTimeGone
May 17, 2012, 03:31 PM
That being said, in 9mm, it was the only semi auto I ever owned where I periodically had to throw away a round due to rechambering. This is a known issue in other calipers, but not so much in 9mm.

My PM9 is what I carry every day.
I never experience the re-chambering issue. I shoot mine pretty often also and I will use the 7 golden sabres that are loaded every third time or so and then use wwb for practice.
I only use the slide lock as Kahr recommends for chambering. Had some ftfs and such for he 1st 100 rds , but no additional failures in 1500 rds or so.

verdun59
May 17, 2012, 04:00 PM
K9, PM9, P380 all feed without a hitch. Maybe because I use the slide stop as advised. All to often I don't read or follow instructions, but in this case I did and hey it works. Nice guns with little recoil for their size.

The_Armed_Therapist
May 17, 2012, 05:06 PM
Mine did that for the first 200 rounds or so, but has been gradually getting better. I couldn't slingshot the slide at first without banging on the bottom of the magazine afterwards. Now, I can do it. It isn't perfect, but like I said, getting better. I'm at about 400-500 rounds right now.

The_Armed_Therapist
May 17, 2012, 05:08 PM
Also, I was frustrated just like you. Every Kahr person kept telling me to "use the slide stop like the manual says!" Um... OK, I get that, but why do I want such a picky gun to defend my family?!?!?! LOL... A few told me that with time it loosens up so that you can do it manually, too, and it's been true so far.

skt239
May 17, 2012, 05:36 PM
I had nose dive issues with my polymer Kahr's but never with the steel ones. My steel Kahr's were early models with the flush base plate, I don't know if that made a difference. I never could sling shot my polymer Kahr's but again, the steel ones were no problem.

Edit to add:

I agree with freedom freak, the slide stop requirement is sort of a deal breaker, especially as a south paw.

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