PM40 Not Returning to Battery All the Time

[Nomad]

I did a quick search and didn't find a solid answer so thought I'd post.
I have a PM40 which has served me well for a number of years. Haven't shot it much (maybe 500 rds) but the last two times I have taken it out it failed to return to battery by maybe a 1/4" after the first shot. A quick bump of my palm returns it but then did it on the next magazine. It has done it with different loads. I will admit my brass is not real shiney and lubing it makes the problem go away but three weeks later without lube I have the same issue. I'm not talking super dry just not freshly lubed. Am I in need of a new recoil spring? Everything is stock as far as springs, barrel & slide. Appreciate any imput. Thanks.

[Bawanna]

A new recoil spring certainly wouldn't hurt. I see the line my brass is not real shiny. Hand loads?
I'd chamber check those loads in your chamber out of the gun or just locked open and see if they easily drop in. Push them in a bit with your finger and then hold it chamber down to see if they fall out on their own.

You might not be sizing enough. Some Kahrs have slightly tight chambers.

I'd try a few quality store bought rounds and see if they drop in and fall out and cycle well.

It's also possible that you have a barrel slide peening issue. I had that with my K40 long ago. Basically it does the same thing but fairly consistently and you should see a little extra wear on the barrel hood. This is a pretty rare thing I'm told so I'd try the other stuff first.

[Ikeo74]

Have you changed the bullets that you are loading? Could be low charged ammo of a bullet shape that doesn't chamber well in your gun. Are you using lead that is not plated?

[Nomad]

Actually the ammo used invloves two handloads and a factory load. The handloads have been through a Dillon Chamber Gauge. Bullets are truncated and ball. To me if the slide goes into battery with just a tap or if the slide is freshly lubed I'm leaning to a weak recoil spring. I can't figure out why it has only occurred on the first shot but it could be coincidence albeit having happened three time is strange.

[muggsy]

It could be occurring on the second shot because the magazine is full and is receiving full mag spring tension on the top round in the mag. Stripping that first round may cause just enough friction to slow the slide down a bit. Of course that nothing but a scientific wild ass guess, but since no one else has offered a suggestion, I'd go with it. Even a blind hog finds an acorn once in awhile. You might try smoothing up those mag lips a bit.

[RRP]

It could be occurring on the second shot because the magazine is full and is receiving full mag spring tension on the top round in the mag. Stripping that first round may cause just enough friction to slow the slide down a bit.

Bingo. Exactly what I thought, but didn't make the effort to type a reply.

A new recoil spring should fix this.

[Bawanna]

If it's only the first shot? So second round feeding or first round chambering?

If it's the first, use the slide release and don't sling shot. If that solves it, then you need to work on your sling shot. Your riding the slide just a tad and not allowing the spring to work to full capacity.

[RRP]

If it's only the first shot? So second round feeding or first round chambering?

Your answer, below.

... it failed to return to battery by maybe a 1/4" after the first shot.

[jocko]

are u

I did a quick search and didn't find a solid answer so thought I'd post.
I have a PM40 which has served me well for a number of years. Haven't shot it much (maybe 500 rds) but the last two times I have taken it out it failed to return to battery by maybe a 1/4" after the first shot. A quick bump of my palm returns it but then did it on the next magazine. It has done it with different loads. I will admit my brass is not real shiney and lubing it makes the problem go away but three weeks later without lube I have the same issue. I'm not talking super dry just not freshly lubed. Am I in need of a new recoil spring? Everything is stock as far as springs, barrel & slide. Appreciate any imput. Thanks.

shooting reloads??? go to the wolfs gunspring site and order their 20.5 outter recoil spring for your PM40 and see how that works out. Irealy think the PM40 should have a stouter recoil spring than the PM9. Ur PM40 comes with a 18# recol spring, just replace the outter spring..open end towards the front of the slide..

[Nomad]

shooting reloads??? go to the wolfs gunspring site and order their 20.5 outter recoil spring for your PM40 and see how that works out. Irealy think the PM40 should have a stouter recoil spring than the PM9. Ur PM40 comes with a 18# recol spring, just replace the outter spring..open end towards the front of the slide..

That's the direction I'm leaning. I find it strange with the small number of rounds I've shot through it that I'm having to replace the spring already. I mean, I have several Kahrs going back to the MK40 and have not had this problem with any of the others.

[muggsy]

Bingo. Exactly what I thought, but didn't make the effort to type a reply.

A new recoil spring should fix this.

Great minds think alike, RRP.

[sas PM9]

N:

In reading through your post again I was a bit surprised with you writing that you lubed your brass. I thought that this was a no-no. Sort of like lubricating the chamber, I thought we were to keep it dry.

I was under the impression that the brass had to "grip" the chamber while under full psi then when psi reduces the brass shrinks and the extraction process begins.

It would seem that a lubricated chamber or brass would throw a monkey wrench in this process.

Thoughts, comments?

-steve

[jocko]

glad

N:

In reading through your post again I was a bit surprised with you writing that you lubed your brass. I thought that this was a no-no. Sort of like lubricating the chamber, I thought we were to keep it dry.

I was under the impression that the brass had to "grip" the chamber while under full psi then when psi reduces the brass shrinks and the extraction process begins.

It would seem that a lubricated chamber or brass would throw a monkey wrench in this process.

Thoughts, comments?

-steve

u asked that question as I have wondered about this to. Not sur eI would want any lube on my loaded rounds. It may not go anywhwere but again it may and IMO if it ain''t on there then it ain't gonna go nowhere, for going someone where on a loaded round is not the somewhere we would want to have. Somewhere in this little essay is a MORAL to this. somewhere

[Nomad]

I had to go back and read my OP. Sorry for the confusion I was not very clear. No I am not lubing the brass just the gun...slide, barrel etc.

[Nomad]

Just in case anyone wants to use this as reference...I installed the 20.5 Wolff recoil spring today and shot about 30 rounds. Seems to have fixed the problem. Wont carry it as my EDC until I put a couple hundred more rounds though it but the good news is it gives me a chance to carry another Kahr as my EDC until then.