Slide Locking Back

[cooger]

I have a 2yo PM40 that has 300-400 rounds through it. Since I bought it the slide has locked back from time to time when the mag still has rounds in it. I'm issued hollow points and I just assumed that the rounds were not hitting the feed ramp just right and jamming. I recently read where there is quite a problem with these guns doing that. It did it to me the other day when shooting and I realized that the slide stop was catching the slide and it was not the round hanging up. Last night I read on another forum where a guy found that the round itself was activating the slide stop as it was forced up in the magazine. I messed with my gun and found that as a round is pushed up in the mag and if its pushed towards the front of the mag then it will catch the slide stop and push it up just a bit. Other folks have said that the slide locking back is caused by the thumb hitting it during recoil. I really don't think this is the case due to the way I hold the gun. I called Kahr today and the guy said right away it was a bent slide stop spring. Mine seems fine though. Any thoughts? Sorry if this has already been asked but I searched and couldn't find it on here. I'm frustrated at spending this kind of money for a gun that isn't functioning right. Other that that problem I love my little gun. Thanks for you help.

[Bawanna]

I have a 2yo PM40 that has 300-400 rounds through it. Since I bought it the slide has locked back from time to time when the mag still has rounds in it. I'm issued hollow points and I just assumed that the rounds were not hitting the feed ramp just right and jamming. I recently read where there is quite a problem with these guns doing that. It did it to me the other day when shooting and I realized that the slide stop was catching the slide and it was not the round hanging up. Last night I read on another forum where a guy found that the round itself was activating the slide stop as it was forced up in the magazine. I messed with my gun and found that as a round is pushed up in the mag and if its pushed towards the front of the mag then it will catch the slide stop and push it up just a bit. Other folks have said that the slide locking back is caused by the thumb hitting it during recoil. I really don't think this is the case due to the way I hold the gun. I called Kahr today and the guy said right away it was a bent slide stop spring. Mine seems fine though. Any thoughts? Sorry if this has already been asked but I searched and couldn't find it on here. I'm frustrated at spending this kind of money for a gun that isn't functioning right. Other that that problem I love my little gun. Thanks for you help.

You've pretty much answered your own questions. If your certain it's not your thumb (and it sometimes happens and you dont even know it, I do it once in awhile) and if you see the rounds in the magazine pushing that slide lock up even a little bit that slide stop spring is probably bent. It's a simple matter to bend it back just a tad or replace. It does seem to be pretty common but it also seems once an owner notices it and fixes it, it usually doesn't recur so perhaps a bit more care when reassembling after cleaning helps. I really don't see how it gets bent myself but they do frequently around here.

[jocko]

rounds should never hit the inside of the slide stop lever. take the slide off and reinsert the slide stop lever, and then insert a loaded magazine and watch for yourself to see if that round in the magazine is hitting the slide stop lever. If it is, I would ask kahr to send you a new slide stop lever, or change brands of ammo to fnd a brand that does not hit that lever on the iinside. Not sure tweeking that slide stop lever spring will solve your issues. The spring would IMO have to be realy out of whack to be allowing this to happen. If it was doing it alot and not ever hitting the inside of the slide stop lever, it could be a defective slide stop spring but it could also be a bad out of spec slide stop lever. A replacement lever seems to solve most of what your talking about.

Rounds can brush by the slide stop lever but if rounds start to raise the slide stop lever, then that is not right. try a different magazine also to see if possable it could be a magazine issue. again one needs to eliminate the possables before panicking.


Be especially sure your thumb is not the culprit. If it isn't you have eliminated one of the possables and then just move forward to some of the above things I have mentioned. Try shooting it left handed to see if u can duplicate the issue...

Some times for reasons I cannot explain a certain brand of ammo can be a cause. In kahrs this is very uncommon, but again eliminate a posssable. such as , if it does it with 124 grain hp and not with 115 grain ammo, then u might be on to something.. You stated "jamming" there is a difference in "jamming" and slide locking back. Hitting the feed ramp will not cause a slide to premature lock open, but it will cause possably jamming. A slide locking open issue is when the slide lock lever locks open the slide ...

[SC Tiger]

I had that issue with my PM9. I spoke with Glen at Kahr and he thought it could be the thumb. I changed my grip so now when I shoot this gun my off-hand thumb hangs way out to the side - looks wierd but it works. They also sent me a new slide stop, but honestly I got the two mixed up and don't know which is in the gun now (one is two-piece, the other is one-piece). I haven't had it in a while. Either way it hasn't happened in a while.

A common mistake is to put the slide stop in and wind up with the stop on top of the spring, so that the spring pushes the stop up. The best way around that is to have the stop at 4 o-clock when you put it in, then rotate it to 3 o'clock when locking it in place. That said I don't think that's your problem or it would happen every time.

I've also seen this with Georga Arms ammo in my 1911. This was because the round had such a fat profile that it hit the stop.

[yamabushi]

I have what may seem like an odd question. How do I make it so my PM40 does not stay open on the last round? I have about 300 rounds through the gun and the Federal 165 HST ammo (that I'd really like to carry) seems to be causing the slide to stop open with 3-4 rounds in the magazine pretty regularly. BTW, the hornady critical defense ammo worked perfectly. I really don't care if the slide stays open on empty. I can count to six, and I will not be carrying a spare mag because I don't expect to ever reload in the real world (no, I'd rather not argue about the benefits of realworld reloading. I know, but I just have to pocket space for an extra mag). I may also remove and file down the mag release button. I started doing this on my P380 when I kept accidentally pressing the release and dumping loaded mags. I haven't had that problem yet with the PM 40, but it may come to that. So, back to the original question, if I want the gun to function normally expect that it doesn't stay open on the last round how do I do that?

Thanks,

Jim

[jocko]

yamabushi. instead of me trying to explai it. go to the kahr tech section ahd hit on propper prepping of your new kahr, it will tell you what you wanted to know. if indeed that doesn't solve the issue, please PM me.

It is supposed to stay opon on the last round though. The gun is designed to do that. I guess you could grind off that little metal end on the end of the follower in the magazine so that it makes no contact with the slide lock lever and the worst you would do is ruin a follower and you get buy just those form kahr and not the entire magazine.

First time I have ever read of anyone not wanting the slide to lock open but it makes some sense if you feel u want it that way. You could still manually lock open the slide if need be. One thing is though you would have to manually rack the slide to load that first roundinstead of using the slide lock lever to load the first round as kahr suggests also..