Luger misfire, ideas?

[JeffK]

I was shooting my '37 Luger the other day, that has had a hundred rounds or so through it since I bought it in March. After 6 shots, number 7 was, pull the trigger and nothing at all - no fire, no click, nothing. I dropped the magazine, pulled the toggle back, and out came the round that had been waiting in the chamber, so I put in a second full magazine.

First round was fine, but second round was the same thing. So I pulled the trigger several more times, and it fired, which surprised me. Next shot, nothing. I dropped the mag again, cleared the chamber, put the mag back in, chambered a round, and it fired fine.

Any ideas on what's going on here, and what might fix it? Clearly the firing pin spring is compressed, but the trigger action isn't releasing the firing pin after the first shot - except sometimes when it does, like after pulling the trigger several times.

[Tidewater_Kid]

Did you clean and oil after you got it? A full tear down and look at everything. It might be a bad spring.

TK

[tangolima]

Looks like the striker follows down (without cocking on the sear). After cleaning, if the problem still persists, I'd suggest check the following.

1. The disconnect. With trigger pulled, pull back the toggle, the trigger should disconnect from the sear, allowing it to return to the cocked position to catch the returning striker.

2. The engagement between the sear and the striker. The engagement should be positive and adequate.

That should do it. PM me if you need help. I did my share of monkeying in that department.

-TL

[JeffK]

Yes, cleaned thoroughly and oiled several times now. Something in the sear mechanism maybe? I don't understand all the things that are supposed to happen internally after a round fires, leading to the next round being ready to fire, so I don't have much of a clue as to what might be causing the misfires.

[JeffK]

PM sent!

[44 AMP]

What it sounds like one problem might be one of a couple.

It's random?

Either the firing pin isn't being held back (cocked) or it is, and isn't being released.

Clearly the firing pin spring is compressed, but the trigger action isn't releasing the firing pin after the first shot - except sometimes when it does, like after pulling the trigger several times.

Ok, this sounds like an engagement problem, some part of the system is engaging just enough to work, most of the time, and not, some of the time.

Since its clean, we'll assume it not a piece of crud randomly interfering, right?

Its been a while since I looked at the insides of a Luger, I'll have to do some research. There are several pieces involved, and each should be checked...

[James K]

Have you checked the firing pin and FP hole for dirt or excess oil?

Jim

[JeffK]

It could be some random piece of crud in some special place that I haven't cleaned, or haven't cleaned well enough. I've had it mostly apart several times, excepting the pistol housing and trigger mechanism, and everything I can see and get to seems ok. The firing pin and spring and guide have been out, all very clean and oiled. And it dry-fires fine, and fired fine the first couple times I took it out. The whole mechanism is complicated enough that I don't really know where to start looking for a cause.

[James K]

OK, here are some things to check. Assemble the gun without the side plate. Make sure the sear is engaging. Work the toggle, then press the trigger bar plunger in with the fingernail. Repeat. If that always works, then the sear engagement seems OK. If it doesn't, then come back.

Now remove the trigger spring and reassemble the gun with the sideplate. Hold the trigger forward and work the action. Pull the trigger. If the firing pin falls every time, the trigger spring may be a replacement that is a tad too long. Grind or cut off a half coil, reinstall it, and try again. If the trigger spring is not the problem, it might be the trigger lever (the "L" shaped part that connects the trigger with the trigger bar plunger). Remove the sideplate, and put a few layers of sticky paper on the top of the bottom (horizontal) part of the "L" and reinstall the sideplate. Test again. If the problem is solved, the trigger lever needs to be tuned a bit. Try the above, then come back and let us know what you find. Don't do anything with a hammer or file or Dremel Tool until you check with us.

Jim

[JeffK]

OK, here's what I did.

1) Assemble with side plate, but without the breechblock assembly.
- Finger off trigger, push barrel forwards, then squeeze trigger. Sear bar spring is being worked as expected.
- Pull barrel back, squeeze trigger all the way, then push barrel forwards. Releasing trigger slightly and re-squeezeing does not work the sear bar spring, as expected. If I release the trigger all the way, I hear a faint click, and the next trigger pull works the sear bar spring.
- Pull barrel back, squeeze trigger all the way, then push barrel forwards. Release trigger gradually until I hear a faint click - this does not happen until the trigger is almost all the way released, the click is just about when I'm taking my finger off the trigger.

2) Assemble as normal but without the side plate. Pulling toggle back and releasing, I can release the firing pin every time by pushing the sear bar inwards on the plunger side.

3) Assemble normally (with trigger spring, I did not take this out), hold trigger fowards, work toggle action. Nothing unusual happens, the firing pin does not release, and if I remove my finger and then squeeze the trigger, it behaves normally.

4) Assemble normally, squeeze trigger slightly, keep squeezing and work the toggle action. AHA!!! If I now squeeze the trigger more, the only resistance is from the trigger spring, AND if I then take my finger off and then squeeze again, it does not engage the sear bar spring, just mush. If I release again, either I hear a faint click and the next pull is normal, OR it returns to the previous state, in which case I have to cycle the trigger at least one more time before I hear the faint click and the next trigger pull is normal and releases the firing pin. This is exactly what was happening at the range, with ammo, so I can reproduce it in the garage by working the action while keeping slighty pressure on the trigger.

5) Remove side plate, put a piece of tape on the underside (down) of the lower arm of the trigger lever, then reassemble normally and repeat (4). No problems, if I keep the trigger squeezed while cyclign the toggle then it might be mushy to squeeze it more, but if I take my finger off it clicks and then fires normally every time.

6) Take the piece of tape off and repeat (4). Exactly the same thing.

So the tape fixes it. Obviously a temporary kluge, but it does point to where the problem and solution are. The trigger lever rocks a bit in the side plate, forwards/backwards. I'm wondering if holding the trigger rocks the lever enough to cause it to hang on the plunger, keeping it from springing out even after my finger comes off?

Either way, the issue seems to be in the trigger lever/plunger area, and huge kudos to tangolima for guiding me this far via PM! I'll attach the pics you were looking for below - I could not get a pic with the plunger depressed, I don't have enough hands, but when fully depressed it seems basically totally inside the hole in the sear bar.

searplunger.jpg
plate1.jpg
plate2.jpg

[JeffK]

One more pic.
plate3.jpg

(By the way, these pics are the best I can do without photo gear I don't have, at least not in digital format)

[James K]

I think I see the (or at least a) problem. The trigger bar plunger (your first picture) appears to be rounded off at the end. It should be a straight cylinder, not rounded or tapered. I suggest you replace that plunger (you probably don't have to replace the whole trigger bar, just drive out the little pin and replace the plunger).

Jim

[JeffK]

Thanks Jim, does look like the grinding on the plunger and the trigger lever are not quite right, and that's where the problem lies. For right now, I'll leave the tape on there as a temporary fix, and meanwhile look around for some new parts to put in. Have to find a local luger expert (SF bay area) who can tune it up. I have several other guns to keep me happy, and I don't intend to fire this often anyways (was trying to compare it to my recently acquired P210 legend target), so not a huge rush.

[James K]

Gun Parts Corp. shows them as sold out, but there are other sources.

If all else fails, they are nothing more than a short piece of round, hardened steel with a notch for the pin. Any gunsmith should be able to make one in a few minutes.

Jim