NOSEDIVES - my take on it

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Originally Posted by JERRY

yes, the are both rimless, but you really should measure a 9mm casing at the mouth and at the end just before the rim, youll find it is tapered.

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I stand corrected, thanks. :yo:

Just checked the .45 ACP, it is also tapered..473 at mouth. .476 at base, .480 at rim.

Under eyeball examanation it doesn't show on either.

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Originally Posted by Steve in Sunny Fla

Of course I've read all the theories on why the kahrs are subject to nosediving rounds, especially on the 9mm 7 rd mags. After having worked on it for awhile, I believe I found the exact problem, and is exactly opposite of what everyone thinks.
The problem is excessive mag spring pressure.
When the mag is full, the rims want to lock from the angle and excessive pressure. Basically when the stripper rail comes forward to pick up the round, the rim holds fast to the indent(don't know the technical name) on the rim below it, and the round rotates downward before the rims unlock. There's the nosedive.
Hold a full mag in your hand, push the top round out by the top rear of the round (where the stripper impacts the round), you'll see what I mean.
I solved mine by shortening my mag springs by 1 complete coil. The rounds strip much more smoothly, and I've had ZERO issues over hundred of rounds.
Of course this is all my own experiences, but I believe it is correct. Thoughts? Steve

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Steve,
I believe your idea has merit and is worthy of consideration. I've long thought that Kahr magazines may be over sprung, but as the follower mod works for me, I didn't pursue it any further (until recently when looking at getting 8 rounds into the 7 round tube). I think one of the reasons the follower mod works is that it does reduce the follower height some which would have nearly the same effect as shortening the spring does. I still believe the follower angle affects how the rounds feed (I built a quick jig that showed me the way the round on the follower sits affects how the rounds stack), but that may be a moot point if shortened springs feed without issue.

Speaking of shortened springs, I just tested a spring that barely holds the follower to the top of the magazine tube. It does not lock the slide back consistently, but it does feed 8 rounds from a seven round tube reliably. I'm not satisfied with the results though. I could live with it not locking the slide back, but I suffered a broken follower and I need to sort that out.

Regards,
Greg

Greg - that's pretty cool, I hadn't considered 8 in a 7. I'll like seeing how that works out. I can tell you're a cheap bastich though, seeing that aguila you're loading. I have an ammo can of it now, already ran through a case from SGAMMO. Im a cheap bastich too! --Steve

Steve - Thanks for your advice. It seems sound and easy enough for me not to **** it up.

I only have TWO magazines and this is my ONLY carry gun/pistol period.

Would you recommend I do this mod?

I have had these mags loaded full for a complete year now with VERY little "alone time" away from the bullets.

Greg - keep up the cutting edge work! I would LOVE to add a round to my 7 round mag. And eventually the 6 round mag too?
Have you tried cutting down one of the extra stiff replacement magazine springs?

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Originally Posted by Steve in Sunny Fla

Greg - that's pretty cool, I hadn't considered 8 in a 7. I'll like seeing how that works out. I can tell you're a cheap bastich though, seeing that aguila you're loading. I have an ammo can of it now, already ran through a case from SGAMMO. Im a cheap bastich too! --Steve

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LOL, guilty as charged. In my defense, I have to say I actually like the 124gr. Aguila. I've never had an issue with any of it and I'm nearing the end of my second 1000 rounds case of it:)

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Originally Posted by MO_Soldier

Steve - Thanks for your advice. It seems sound and easy enough for me not to **** it up.

I only have TWO magazines and this is my ONLY carry gun/pistol period.

Would you recommend I do this mod?

I have had these mags loaded full for a complete year now with VERY little "alone time" away from the bullets.

Greg - keep up the cutting edge work! I would LOVE to add a round to my 7 round mag. And eventually the 6 round mag too?
Have you tried cutting down one of the extra stiff replacement magazine springs?

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Testing is still in the infancy, but I will be giving cut down springs a go (thanks for reinforcing that:)). As to the 6 round mag, I don't have a CM/PM Kahr so I won't be venturing into that water.
Regards,
Greg

i havent had a malfunction with my 6 or 7 round pm9 magazines.....i think if i do i wont muck around with trying to make crap into a rose....i will just buy new magazines.

that said, if your current magazines have worked all along and all of a sudden give you propblems id say just change out the spring.

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Originally Posted by gb6491

Testing is still in the infancy, but I will be giving cut down springs a go (thanks for reinforcing that:)). As to the 6 round mag, I don't have a CM/PM Kahr so I won't be venturing into that water.
Regards,
Greg

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My cw9 is cut down to a covert; I run a 6 round mag and 7 rounders with spacers. I can mess around with the 6 rounder if it'll help. Steve

That really would help Steve!
Thank you from all of us pm/cm shooters :)

The second round in my 8-round mag just hasn't risen up to the same position the first round was and allowing the slide to pick it up consequently the slide will lock back (open) a couple of times recently. Kind of like that second round was a micro fraction longer than the rest and wedged cross-wise in the mag and wouldn't rise up into position. Changed out that round and everything was smooth after that. Is this what's considered a nose-dive?

Quote:

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Originally Posted by Steve in Sunny Fla

Of course I've read all the theories on why the kahrs are subject to nosediving rounds, especially on the 9mm 7 rd mags. After having worked on it for awhile, I believe I found the exact problem, and is exactly opposite of what everyone thinks.
The problem is excessive mag spring pressure.
When the mag is full, the rims want to lock from the angle and excessive pressure. Basically when the stripper rail comes forward to pick up the round, the rim holds fast to the indent(don't know the technical name) on the rim below it, and the round rotates downward before the rims unlock. There's the nosedive.
Hold a full mag in your hand, push the top round out by the top rear of the round (where the stripper impacts the round), you'll see what I mean.
I solved mine by shortening my mag springs by 1 complete coil. The rounds strip much more smoothly, and I've had ZERO issues over hundred of rounds.
Of course this is all my own experiences, but I believe it is correct. Thoughts? Steve

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Steve,

Would you post a photo of your "cut-down" mag spring? I'd like to try it but I don't want to cut in the wrong place.

Dave
PM9