[Big Bird]

I've seen a lot of posts over time about specific malfunctions with Kahr pistols regarding premature slide lock back (ie: slide locks back with rounds still in the magazine) or with guns that will not lock back on an empty magazine, or even guns that lock back after every shot. Another related symptom of these problems is also that its very hard to remove the slide stop from the gun during disassembly. While all these problems may have many causes the single biggest culprit in my experience is with the slide stop spring.

The first thing you need to do is understand that the little slide stop spring serves two very critical functions and that if its damaged or not installed properly you WILL have slide lockback problems of one type or another. The other important thing you need to know is its VERY EASY to damage the slide stop spring during routine disassembly and not even know it because it is small, is an awkward location, and its design and function is not very intuitive.. I have seen many Kahrs with badly bent slide stop springs from owners who didn't know what they messed up or how and why it mattered. They just knew their gun was a POS...So if you own a Kahr here are the things to know and look for:

What the slide stop spring does--Its primary function is it applies downward spring pressure on the slide stop with sufficient force to keep the momentum of the gun during a firing sequence from bouncing the slide stop up and prematurely locking back the slide. The second function of the slide stop spring is it provides tension in the little groove on the shaft of the slide stop that keeps the slide stop from working out of the gun sideways as the gun is fired. Both of those are important roles for such a tiny hunk of wire about the size of a dad-gummed office staple!

Where is the slide stop spring and what should it look like
The slide stop spring is a tiny curly-Q shaped bent metal spring stock that can be found attached to the left outside of the frame between the slide stop cut out and the hole that you insert the slide stop shaft through to assemble the gun. The slide stop spring is held in place and ROTATES AROUND (key point you need to understand--more later) a tiny torx screw and washer. The slide stop spring also has a 90' degree bend that inserts into a small hole drilled in the frame at about the 2 0-clock position as you look at it and this acts as the fulcrum for the spring as it is manipulated AROUND THE TORX SCREW in operation. THIS IS IMPORTANT--the end of the slide stop spring must extend into the slide stop cutout and MUST enagage a small tab on the top of the slide stop when it is installed. You cannot see this with the gun fully assembled but if you take the frame by itself and insert the slide stop you will see the tiny bit of slide stop spring sitting ON TOP of the little shelf of the slide stop lever. Again, this is very critical! It provides the downward spring force required to keep the slide stop from jumping up under recoil and prematurely locking back the slide on an empty magazine. If you look down into the partially assembled frame you should also be able to see how the slide stop spring engages the groove in the slide stop shaft that keeps it from walking out.

COMMON PROBLEMS WITH THE SLIDE STOP SPRING Kahr has a VERY good video on Youtube about how to PROPERLY assemble/disassmble a Kahr pistol and one of the things they are VERY explicit about is to make sure the slide stop spring is in the correct postion as you put the gun together. Unfortunately many people don't read/watch instructions and they also make some inadvertant mistakes that can cause issues with this critical component. So the first thing I'm gonna tell all of you is to watch the stupid video because even you "know-it-all's" will learn something. Second thing I frequently see is that people often fail to properly line up the "link" on the bottom of the barrel with the slide stop as they assemble the gun and they get some resistance trying to push the slide stop home. At this point they wack it a few times (cause that's how its done right?) and in the process of wacking the slide stop which is now not properly aligned with the slide stop spring--they proceed to bend the spring back into the frame and it will no longer engage the slide stop even after you realize that the slide stop shaft didn't engage the barrel and you re-assemble correctly. The damage is done. Its a small unobtrusive spring and you don't even notice it. But the daggone Kahr POS is no longer working and to make matters worse the slide stop is now harder than hell to remove! (which is because the spring no longer can move as designed because you bent the hell out of it and remember--the spring also enages the slide stop shaft and helps retain it during operation right? See how its all related?

The second problem I see is people get in and tinker with the pistol and they find the torx head screw and washer that hold the slide stop spring in place and they think like any other "know-it-all" gun nut that screws gotta be tight! So they crank that sucker down....And what they have just done is to limit the operational range of the slide stop spring and make it impossible for the magazine follower to push UP on the slide stop on the last round. Then your stupid POS Kahr will no longer lock back on an empty mag. The PROPER way to install this screw is to leave enough play under the washer to allow the spring to move freely through its full range of motion as designed. Again, take the disassembled frame, put the slide stop in, insert an unloaded magazine. The pressure from the unloaded mag follower engaging the slide stop should visibly move the slide stop UP a good 1/8" If it doesn't move you have too much screw tension on your slide stop spring assuming the spring isn't bent and mangled because you assembled the gun wrong and dorked it up.

Lastly, a slide stop spring that is bent and inoperable can usually be bent back to serviceability with a couple of pair of needlenose pliers. However, I recommend you do this with the spring removed from the frame. Just remember when you put it back together to be sure to NOT torque that torx srew/washer back down or you'll have another problem.

Look, its a little bit of a quirky problem unigue to Kahr's and it takes some understanding of the gun and its design and some attention to detail when it comes to assembly/diassembly of the slide stop lever to help avoid the problem. It doesn't help that there are no other guns with a slide stop spring design issue like this so its not something your average "know it all" gun crank can usually diagnose and deal with. So it helps a lot if you understand how things should work/look and also allows you to continue to identify or eliminate this funky design issue and troubleshoot malfunctions. There are certainly other things that can cause slide lock back related issues with most any gun including Kahrs like worn/out of spec magazine followers, weak magazine springs, or even worn magazine release levers. So you need to be aware of those as well. But in my experience with Kahrs and helping people solve their issues this slide stop spring thingy is a very common one that can be mitigated with a little training and experience. FWIW, new slide stop springs are $6 from Kahr! You might want to order one and stash it in case you get a little ham handed the next time you are putting your Kahr back together.

Cheers!

[eracer]

Thanks for this. I am 150 rounds into the break-in period of my PM45. It's always good to hear first-hand tips that will help keep things running properly.

[PhantomF4E]

Good write up. I'd say that is suitable for a sticky

[halfmoonclip]

Up to a point, I'll agree, and thanks for the post BB. Let me share my experiences.
A buddy had a Kahr 9mm that responded exactly as BB suggests, and a new spring solved the problem.
OTOH, I'm now on my third P380. When I first got it, I was having slide stop engagements with rounds left in the gun. I ordered a spring and slide stop from Kahr, but while they were in transit, I ground off the slide stop finger completely, and the problem went away. Somehow the rounds in the mag were brushing the slide stop finger and making it engage. When the new spring and stop arrived, I stoned it before installing it, and had no problems.
When Kahr sent me a new frame because of extraction problems, it also had unwanted slide stop engagements. I took off some of the end of the slide stop finger, and the problem went away.
When I finally swapped the troublesome gun for an entirely new one (one that is now at over 200 rounds without an extraction/ejection problem), I also had to stone the finger to avoid slide stop engagements. Wish I had measured HOW MUCH I've been taking off, but mostly I round and smooth it. Since the finger mods, this gun has behaved in every regard. I really like an LCP for reliability , but the ergonomics and sights are so much better on the Kahr.
I also shoot a lot of LTC practice ammo, which may aggravate the problem.
Moon

[Big Bird]

halfmoon,
As I said in my post the slide stop spring is not the only thing that can cause slide lockback problems. I have had the exact same problem you described in a SIG .380 and also in a CZ-75B believe it or not....

[halfmoonclip]

Originally Posted by Big Bird

halfmoon,
As I said in my post the slide stop spring is not the only thing that can cause slide lockback problems. I have had the exact same problem you described in a SIG .380 and also in a CZ-75B believe it or not....

With the abrupt action of small autopistols, I can absolutely believe it.
BB, do me a favor and throw a vernier on any unmodded P380 slide stop you may have; (I'm assuming you have one...perhaps an unwarranted assumption). I'd like to see just how much was removed; truly it wasn't a lot, because all I used was a stone.
It is my impression that Kahr makes the slide stop finger a wee bit longer than it actually needs to be, or else it is somewhat sharper on the end than necessary. A contributing factor in my problem may have been a mold line present on some of the Lead Truncated Cone bullets that was catching the slide stop finger. I didn't shoot a huge amount of my carry ammo (at the price of Gold Dots...) to encounter the issue, but it has behaved perfectly with those as well.
I'll open a separate thread about my extraction issues; love to know if anyone else encountered them.
Thanks and good work on the sticky,
Moon

[Big Bird]

Don't have a P380. Only .380 gun I now own is a Ruger LCP.

[halfmoonclip]

Originally Posted by Big Bird

Don't have a P380. Only .380 gun I now own is a Ruger LCP.

...and I no longer have a P380. After an initially positive experience with the replacement gun, it too began to misbehave. I had misfires and then another one of the 'failures to eject' ; ended up with a Gold Dot casing 180* in the ejection port. Don't know what the issue is, and I no longer give a fat rat's derriere .
I am done with Kahrs, period. Had an earlier Kahr 9mm and it gave grief as well, but the great ergonomics lured me back. Should have known better.

Anyway, traded the little bugger away today, mostly to keep me from clamping it in a machinist's vise and playing the drum solo from 'Gadda da Vida' on it with a big ball peen hammer.
I'll enumerate some more details in the other thread I started. Take care and good talking to you.
Moon