Chambering the first round, a slingshot modification

[gb6491]

How much would you say you took off the top? I am having a tough time reading your calipers. If I decide to only sand the top how much would you suggest i take off.

By the way, good stuff. Must have taken some b*lls to do it on a pig in a poke.

Just under .06" on the calipers. I suggest repeated testing as material is removed to preclude manufacturing tolerances causing any issues.
Regards,
Greg

[Thunder71]

After further testing the gun still fires 100% of the rounds but the mag can still lock up like they usually do, even tried the 2nd step - might have to sand a little more.

[OldLincoln]

Greg, do you still have the nose gap between the top and second round in the mag? Sorry, I'm still trying to get my arms around this thing. Also, have you or others replaced mag springs after the mod? If so how did that work out?

[gb6491]

Greg, do you still have the nose gap between the top and second round in the mag? Sorry, I'm still trying to get my arms around this thing. Also, have you or others replaced mag springs after the mod? If so how did that work out?

Hi Old Lincoln,
There is still a gap there. Visually, I would say it looks the same. Physically, the top round in a magazine with the modified seems less springy/less range of motion if you press down on the nose of it.

Let me expound on my thought process for this modification.
1. I knew a ProMag magazine would feed the rounds after watching a video posted on YouTube.
2. I could verify this after getting a ProMag magazine for myself.
3, I was able to duplicate those results with a ProMag follower and spring in a Kahr magazine tube.
4. The ProMag spring and Kahr spring seemed about equal in the amount of pressure the apply to a follower in a Kahr magazine tube. BTW, I don't have an extra Kahr spring to see how a replacement might work, but one of my Kahr magazines is relatively new.
5. As the springs are a wash, this led me to believe that the follower is the key component.
6. Side by side, it's pretty obvious that the ProMag provides front edge support differently than the Kahr follower does. In the following photo, I've highlighted that difference.

7. I decided to try and mimic that difference when modifying the Kahr follower. I've highlighted the next photo to illustrate what I was able to accomplish in comparison to an unmodified Kahr follower (highlighted in red):

I should have highlighted the center of the followers as well becuase I did move the point where it starts it's downward slope forward (while reducing it's amplitude) on the modified mag.

I know this is a "fly-by-the-seat-of-your-pants" approach, but I'm more than pleased with the result (pretty much as I imagine the blind pig is with his acorn).
Regards,
Greg

[Bawanna]

Looks like some very well thought out logic to me. I seriously think your onto something here. Your reducing the chance of a nosedive which is what seems to be what we hear most often.
If this isn't the cure I think your on the right track to getting there.

[gb6491]

Thanks Bawanna.
I'm convinced that this is a viable modification. Previously, if I wanted to charge my CW9 without using the slide stop, I needed to go with a very brisk, overhand, slingshot. If it was hollow points, make that a very, very, brisk operation. Post modification, I can pretty much ride the slide to a stand still and feed ball. Most hollow points are not far behind that, with my most aggressively cupped ones requiring only a nonchalant release of the slide. I've done both of my magazines now and will do so with anymore I acquire. Here's another video I just shot to try and show how easily both types ammo feed: http://www.youtube.com/watch?v=KFFwz0-jrYo

FWIW, My CW45 has always been easy to charge (once the magazine is seated)
http://www.youtube.com/watch?v=45CfcRIlDto

Regards,
Greg

[Serafino]

Interesting that the lowered position of the round on the follower is not a problem, since it appears the modification does not lead to the follower rising enough higher in the tube to make up for it?

I guess the slide stop would stop the upward travel in any case, which makes the success of this mod even more interesting and makes me wonder whether a redesigned follower with the new geometry but the old height level might work even better? Or are the original followers so 'off' in their geometry that even the changed relationship of round to slide stop tab is an improvement?

[gb6491]

Interesting that the lowered position of the round on the follower is not a problem, since it appears the modification does not lead to the follower rising enough higher in the tube to make up for it?

I guess the slide stop would stop the upward travel in any case, which makes the success of this mod even more interesting and makes me wonder whether a redesigned follower with the new geometry but the old height level might work even better? Or are the original followers so 'off' in their geometry that even the changed relationship of round to slide stop tab is an improvement?

My apologies for this, but I forgot to take any photos of how the magazines look with rounds in them and the modified /unmodified followers in place.
The feed lips of the magazine ultimately control the height of the round as it is presented for chambering. So this is constant with the modified and stock follower. The angle of the stock follower is also maintained by the mod. What the mod does is increase the length that the follower supports a cartridge. In the following photo I've high lighted where cartridge support ends for the stock and modified followers.

This increased support for the bottom round in a stack is apparently enough to affect how the whole stack acts.
It's also worth noting that becuase the stock follower is tapered at the top, the modified follower actually stops at about the same height. This makes for little change to the point where the slide stop and follower engage.
Regards,
Greg

[Serafino]

Ah drat I wasn't taking everything into account in my thinking. Sorry about the red herring.

[BEARDOG]

Greg,
I tried your mod. on one of my followers as you have shown. I only have 1 each- 6rd,7rd,8rd - 9mm mags for my CW9 and CM9. I just did the one from the 8 rd. mag.
I can usually slingshot both my Kahrs without too much trouble, but this would be a welcome upgrade to the Kahr mags as we all know, they can use all the help they can get....

I have tried it in all the mags, and I have noticed some improvement hand cycling the rds. I agree that the improvement stems from the increased nose support, by moving the "pivot" point forward it helps stabilize the cartridge. I can't say it is a 100% can't make it jam when riding the slide mod.
But it shows an improvement, and when normally racking the slide, I think it will make it more trouble free. I have not fired the guns yet with the mod so I can only assume it will work as yours does.
I can also tell a big difference in ease of function in the 2 types of hollow point ammo I have tried it with. It seems the 147gr Rangers are much easier to load then the 124gr Gold dots. The Rangers have a different profile that let them hit the ramp slightly higher I think is the reason why? Anyway, the Rangers go in like butter and the G.D. still can hang if done slowly.

I sanded the belly maybe slightly father forward then yours, sanded down the top, and I also beveled the sides to fit the angle of the feed lips, and also to make sure the slide lock pin come up far enough to positively engage the slide stop and it does that well. I will have to play with it at the range some to see how it preforms.

One thing I do wonder about after being used for sometime, Is if this mod will cause any wear on the follower? It would seem Kahr made it the way they did for a reason???, and I wonder why?
Time will tell.

Pic of mine, modified follower on top vs. a stock on bottom.