NOSEDIVES - my take on it

[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

[Ikeo74]

I think the same problem could be resolved by simply loading the magazine 1 bullet short.
Then after the springs take a set the mag would hold that last 1 bullet.

Your theory is correct but the springs will need to be replaced sooner after cutting off 1 coil. (my theory only)

[Ikeo74]

I believe this method could solve the whole Kahr springs problem including the stiff recoil springs. If it works Kahr would no longer have a spring problem. Solution follows:

Kahr, Develope a spring viabrating compressor machine. Take all new springs and run them through this machine to "pre-set" 100% of all Kahr Pistol springs. Compress each new spring 500 times to effect the set. Then install them in the new guns as a "pre-set" spring. This would also eliminate the 200 round break-in procedure because the springs are already set, and also eliminate the magazine tight spring problem.

Try it, and you can compensate me later for this information with a new MK9. Ikeo74 :D

[Charlie98]

Loading one cartridge short in a CCW magazine is not an option (my theory.) So far, my 7rd CW9's mags run 100% without issues.

If you look how the top cartridge is presented in a full magazine, it is at a different angle than the cartridges below it... when the bolt face hits the rear of the top cartridge, unless it releases immediately, it would tend to rotate down to meet the angle of the cartridge below it. The idea is it will move forward and up enough to hit the feed ramp and feed instead of nosedive into the front edge of the magazine or hit the feed ramp at such an angle as to obstruct feeding.

I do notice the subsequent rounds feed much easier as you go through the rest of the mag, so your idea of cutting a coil off the mag spring seems like a good idea, but the problem may lie with the last rounds and holding the slide back when the mag is empty, especially on a old or fatigued magazine spring... a misfeed or slide forward on am empty chamber on a CCW weapon is not acceptable (again, my theory.)

[Steve in Sunny Fla]

When the spring is shortened, it actually stiffens the spring, but reduces the preload on it. Because of the reduced preload, the cut spring will take less set, and actually maintains it's tension longer. I'm also running 22# springs and have had no issues with feeding or slide lockback. I've tried the follower mods, etc; cutting the spring has been the best resolution I've seen yet. Steve

[JERRY]

the 9mm is a tapered round, any idea why this still happens with the non tapered non rimmed .45acp?

[Steve in Sunny Fla]

the 9mm is a tapered round, any idea why this still happens with the non tapered non rimmed .45acp?

Haven't worked on a 45, but cutting also helped my cw40 feed better. Steve

[Ikeo74]

the 9mm is a tapered round, any idea why this still happens with the non tapered non rimmed .45acp?

Niether the 9mm or the 45 ACP are tapered and both are rimless. The only difference is in the diameter.

[wyntrout]

I think that magazine/mag well fit, or slop, and pressure on the lower part of the magazine... the way it's gripped can move the top of the magazine to the right enough, too, that the nose of the round hits the extreme right of the feed ramp and "sticks".

I put a new follower in a 7-round K9 magazine and was trying it in my P9, and I kept having nose-jams on the right side as I mentioned. I took pliers and tried to "tweak" first the right forward lip of the mag and then the left forward to the left a bit... really infinitesimally, as the pliers slipped off, but enough "tweak" that the nose-jams stopped and rounds chambered without any more problems. I used #400 grit sandpaper to touch up any possible scratches on the feed lips from the pliers.

The magazine material is very tough and you don't need to make a noticeable BEND to the left. I initially thought that I hadn't moved the lips at all, but it was enough to get the bullet noses into the "groove" of the feed ramp, rather than the side.

Wynn:)

[JERRY]

Niether the 9mm or the 45 ACP are tapered and both are rimless. The only difference is in the diameter.

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.

[Ikeo74]

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.
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.

[gb6491]

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
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.
L_2kg9R9bHA
Regards,
Greg

[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

[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?

[gb6491]

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
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:)


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?
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

[JERRY]

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.

[Steve in Sunny Fla]

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

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

[MO_Soldier]

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

[Allen]

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?

[SixPak]

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

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

[Ikeo74]

SixPack, read this post about mags and mag springs for information.

http://www.kahrtalk.com/showthread.php?t=17326

This is about 8 round mags but the spring problem is the same.

[TheTman]

My CW45 would not feed from the 7 round extended magazine. The first 3 or 4 bullets usually nosedived or once in awhile would stick straight up. Once I got down to the last 3 or 4 cartridges the mag fed fine.
Just thought I'd thow that out there in case it helped anyone figure things out.