CT 380 Last Round Hold Open

[chengpu42]

I am having issues with last round hold open on my Ct380 with 2 handed grip. Strong hand no problem, weak hand no problem, with a 2 hand grip if any part of my offhand or thumb makes any contact with the slide stop it will not lock back. I have tested the slide stop and even a slight brush is enough to prevent it from holding open. Does anybody have any ideas on potential trouble shooting?

I have monkeyed with the slide stop spring some. Is there a ideal position the end of the spring that makes contact with the slide stop it should be in? Higher, lower, middle? According to the Kahr leaflet the back half of spring should be immobile (screw tight enough to prevent flex). When i originally got the firearm the back half of the spring had some play in it and screw/washer was not making good contact with the spring. I added a small piece of rubber band under the screw washer in order to hold it tight to the spring.

I have 2 mags and neither is more effective. I have pulled the springs out to increase tension and manipulated the springs in other ways, no good. I have added some small plastic shims under the base plate to increase tension, no good. I have noticed that the back of the follower is much harder to push down than the front. In fact the front of the follower that contains the mag catch is very easy to press down. I added the Magguts components and that did not help. When i added a few plastic shims under the base plate with the Magguts i did start to have some success with last round hold open. I would say 50% of the time it now works.

It seems that there is not enough tension (mostly in the front of the follower) in the mag spring to overcome any pressure applied to the slide stop.

[DavidR]

I don’t have any suggestions but I’ve had some issues with failure to lock back in my CT380. It seems to be mag specific for me so likely not the same problem as you’re having.

[5.56x24]

Here's a few things you might try:

Take the gun apart, loosen the slide stop spring retaining screw using a #6 Torx driver, then insert the slide stop into it's left side hole but stop short of going in until the spring indexes into the recess around the base of the slide stop pin. Now tighten the slide stop spring retaining screw - and remove any and all additional material you have located there - just the thickness of the tiny retaining ring. You want to tighten the screw "snug" but not tight since it's anchored into polymer. If the screw is "out" far enough it will prevent the slide stop from seating fully.

Take the slide stop and run it up and down the left side of the slide along the bottom in the same manner as happens during normal functioning. Apply pressure outward - pressing the slide stop against the inside of the slide to smooth and polish the inside face. Also, run the slide stop into and out of the slide stop notch on the slide to smooth up that transition.

If you test the slide stop with no slide stop spring in place the first thing you will notice is how GREAT it works! With the gun fully assembled except for the slide stop spring, the slide stop is easily pushed upward by the magazines - including the reluctant ones. So this tells you the issue is all about the spring. The spring acts in two ways - it has a short leg that applies downward pressure on the slide stop arm, and it has a "bow" on the front aspect that indexes into a tiny groove running around the base of the slide stop pin, and also applies pressure, which is why you have have to use something hard to press the slide stop to get it out. This is by far the greatest pressure preventing the slide stop from working - not the tiny leg projecting out. This is the rationale behind tightening the slide stop spring with the full-diameter of the slide stop in pressing against it and this does loosening things up a bit.

After these steps even your weakest mag should be able to get the slide stop to lock up.

As a final resort, the slide stop spring can be removed and, using tiny, needle-nose pliers, grab it at the "top" of the bow and just past the bow on the forward curve, then bend it slightly - a good "flex" then reinstall and see how it lessens the pressure being applied to the slide stop in. Once slide stop pin pressure is attenuated, the slide stop will function as intended.