CM9 Mag Question

[Pappy]

Does anyone know if the K 820 7 round mag fits flush in the CM9...
Or does it stick out of the mag well with a big gap...

This is the info I found but no photo to show it installed....

7 Round 9mm Magazine "K820"

7 rounds, 9 mm, stainless steel. Fits all Kahr 9 mm models except TP9 & T9.

Thanks for your help...

[jocko]

cm9 and PM9 flushg fit mags are 6 round, anything more than that will stick out, so yes it will stick out.

[Pappy]

jocko....Thanks for the reply....

I have seen some folks modify their 6 rounders with polymer retainers and base plates....but require some fitting work....

I just want to close up the gap on my 6 rounders....

I wish there was a mag with a more flush fit 6 or 7 rounder and no gap...

[LorenzoB]

Pappy, I am working on CNC machining one. I have it mostly done and hope to post some photos soon (later this month maybe). I really wanted a magazine bottom plate that fit the gun better, so I decided to make one myself. Tooling and material cost was higher than I hoped, so maybe I will sell some when it is done. I'm sure everyone here is tired of hearing me bring up my project, but it is really cool to me, so I can't help but bring it up when someone mentions they aren't pleased with how the magazine fits the grip.

[mr surveyor]

Lorenzo... that would be a really nice accessory, if you can make it so that it does not allow grip pressure on the front to cause the mag lips to cant forward from torque and lock up the whole works.

[Deano]

That particular magazine will stick out with almost a full cm. between the butt of the frame and the plastic base plate.

[jocko]

what cvleans it up more

jocko....Thanks for the reply....

I have seen some folks modify their 6 rounders with polymer retainers and base plates....but require some fitting work....

I just want to close up the gap on my 6 rounders....

I wish there was a mag with a more flush fit 6 or 7 rounder and no gap...

with no mods needed is to just get the magazine and floor plate finished in black. I sent mine off a few years ago to a finisher that someone here posted and they did a super job and they show zero wear. thegap now to me anyhow is acceptable. I tried spray painting the mags and floor palte but it just never held up like therefinisher did for me. Some have also put an "O" ring at the bottom of the mag to fill that gap but again, different strokes for differentr folks. to me my PM9 is a tool. I sometimes think this gap is by design to assure that all mags will lock in place. And also I feelthegaps on some kahrs are more spacey than othersw, so how is one gonna design a floor plate to sell that he can beassured will fit perfect??? IMO accept what u got and carry it and shoot it like u stole it..

[LorenzoB]

The extended mags Kahr sells have no gap at all (on my CW9) and require a very hard tap... I don't really like that, so I feel a small gap IS important, but I believe it doesn't have to be THAT big. My design has about a 10 to 15 thousands gap (on my gun). The gap might end up slightly bigger or smaller on other guns, but it shouldn't be an issue on most guns, as long as Kahr uses industry standard tolerances. My gap feels much better than the normal gap and almost feels like no gap at all, but without having to slam the mag in.

I do whole heartedly agree with Jokco when he said "it is a tool", Kahr designed it very well and we shouldn't worry about this stuff too much. I am not obsessing with this, I just want it to be a little better (and I know there is always room for improvement)... AND this is the kind of thing I do for a living except I don't normally get to cross over into fun gun stuff.

[jocko]

question: andwhat would "industry
standard tolerances be???

[LorenzoB]

Better than woodworking tolerances... My gap was over 1/32". If Kahr Quality Control is holding a tape measure up to these parts to make our guns, then we are all in trouble.

In CNC machining, Plastic injection molding, and CNC punch press, it is common for +/-.005 (or better).

I do have to consider tolerance stacking when dealing with multiple parts, but even in an imperfect world, statistics would say you would RARELY assemble all pieces that stack the tolerances in the same direction (it is like winning a "bad" lottery). I don't have my drawing with me, but I think I had about a .040 gap between the bottom of the plastic grip on all my magazines. They all varied by 2 to 3 thousandths. That tells me that they are holding at least some of the tolerances fairly tight, but I won't know for sure until they are tried on other guns.

Now, I believe it may be that Kahr is trying to use the same mag and base plates on so many different guns, that the gap needs to be that big on my CW9 because maybe it is smaller on other models. I understand that, and I am not asking Kahr to change that because it is probably a design requirement for that reason. I believe my design would not have any issues on most, if not all CW9's. We will just need to try it on others models and make adjustments for those. Maybe there will be many different bottom plates to accommodate all the models.

I'm not looking to sell tons of these. I just wanted to make one for me originally. Kind of like how someone might spend hours modifying their follower or pay to have a coating done. I would like to sell some to recover some costs of doing it, but more important than the money, is I think some out there might actually like it and want one too. If they buy one and it didn't fit quite right, I would have them send it back for a full refund or make one that fit better for them. I wouldn't "stick it" to anyone. We all don't need more enemies in this world. There are already enough BG's to carry ammo for!

[LorenzoB]

Sorry for the long explanation above. After I posted I noticed I rambled on a bit.

[LD48750]

When you're ready to start selling them, let me know.