CM9 slide not locking back

[DavidR]

May want to consider trying a factory new stock magazine ,when we alter mags, guns in any form it's a gamble.

Good suggestion. Thanks. You’ve reminded me that neither of the stock mags for me CT380 which has 800 rounds through it lock back the slide anymore. Need to look at that spring too.

PS - I’ve shot them one handed and the problem persisted so it’s not my grip.

[DavidR]

With a T5 to loosen the screw, I adjusted the spring to what I think looks like Greg's picture (see below). Now, when hand cycling, none of the 8 mags lock back the slide (whereas before 2 of the mags did lock it back). I then replaced one of the stock followers in a 6 round mag that has a Lakeline plus 1 billet with a Lakeline metal follower and that mag now locks the slide back. The Lakeline site says that the metal follower isn't compatible with the plus 1 billet in 6 round mags so I put the stock follower back in.

What's odd is that I have four 7 round mags for my P9 (2 with Magguts and 2 with Lakeline plus 1 billet). When hand cycling, all of those mags lock the P9 slide back but none of them lock the CM9 slide back. Maybe the slide stop spring in the CM9 has weakened? I ordered a couple of new ones from Kahr so when they come in I can test that.

I really appreciate all the help and am open to more suggestions.

[gb6491]

With a T5 to loosen the screw, I adjusted the spring to what I think looks like Greg's picture (see below). Now, when hand cycling, none of the 8 mags lock back the slide (whereas before 2 of the mags did lock it back). I then replaced one of the stock followers in a 6 round mag that has a Lakeline plus 1 billet with a Lakeline metal follower and that mag now locks the slide back. The Lakeline site says that the metal follower isn't compatible with the plus 1 billet in 6 round mags so I put the stock follower back in.

What's odd is that I have four 7 round mags for my P9 (2 with Magguts and 2 with Lakeline plus 1 billet). When hand cycling, all of those mags lock the P9 slide back but none of them lock the CM9 slide back. Maybe the slide stop spring in the CM9 has weakened? I ordered a couple of new ones from Kahr so when they come in I can test that.

I really appreciate all the help and am open to more suggestions.

The slide stop spring's function is to bias the lever down to prevent it from engaging the slide unintentionally. The magazine follower and magazine spring push the stop up to lock the slide back.

Without the slide on and with the stop in the frame, insert an empty magazines and see if they lift the stop. Check this against you P9.
If they have similar lift. Then put the slides on and do a comparison.

How easily and securely does the CM9 lock back when manipulating the stop by hand?

Regards,
Greg

[DavidR]

Thanks Greg. Understanding the function really helps.

With the slide off, slide stop pin in and a mag in the P9 slide stop lever is raised much higher than the CM9. P9 on top.


I also noticed that the cutout in the slide is a little more rounded on the CM9 than on the P9. P9 on top.


The CM9 is more difficult to manually lock back the slide. Even when locking it back by hand with an empty mag inserted, it will sometimes go into battery by itself. Could it be the mag catch is worn?

[oldtimer]

Just some random thoughts with the desire to help, I had a promag that would not lock back in my cm9 I replaced the follower with a new kahr stock follower and
it solved the problem, I use that mag only at the range. I do not have much long term faith in Kahr mag followers to be honest.

[DavidR]

Just some random thoughts with the desire to help, I had a promag that would not lock back in my cm9 I replaced the follower with a new kahr stock follower and
it solved the problem, I use that mag only at the range. I do not have much long term faith in Kahr mag followers to be honest.

I thought about that too but my Kahr 7 round mags don’t have that many rounds through them. At most 200 per mag. They lock the P9 back fine but not the CM9.

[gb6491]

Same results with the stops swapped?

Does it seem that the window in the CM frame is preventing the stop from rising higher?

It looks to me that the window is not quite vertical at the top. My CW9 for comparison:



Regards,
Greg

[Bawanna]

I think I'd try rotating the spring upwards just a bit and see if that makes a difference. Perhaps the spring has too much tension and is keep the slide lock down harder than it should.

[DavidR]

Thanks Greg for sticking with me on this. I will check if the frame is impeding the stop. Probably won’t get to it until tomorrow (sometimes work gets in the way).

Bawanna - I did try bending it up a little and lock back improved a lot when hand cycling with an empty mag. Now that Greg explained to me how this works, I’m thinking too much “up” will cause lock back with rounds still in the mag so I’d have to test that too.

[DavidR]

I took a look this morning.

1. The frame is not impeding the stop.

2. Stock followers don't lock back but Lakeline follower does.

3. I rotated the spring upwards a bit and now the stock followers lock back; hand cycled a mag and it worked as it should.

Still not sure what to make of this. I'll test it at the range to make sure there's no premature slide lock. May just replace the spring when the new one arrives.