Tuning for Reliability

[Michael Zeleny]

Originally Posted by SIGP2101

In a mechanically sound device slow to medium speed burning powder will solve all of your problems. Modern powders are too fast and snappy for P08. Off shelf ammo being loaded with very fast BR powders are not ideal food for P08s. Reason for that is to ensure proper functioning of majority carry weapons on today's USA market. Most of them have pipes less than 10 cm long. Nitrocellulose based powders from the beginning of the 20ieth century were not fast BR powders.

I understand that. The challenge is to make the gun work with modern factory ammo.

[Sieger]

Originally Posted by SIGP2101

In a mechanically sound device slow to medium speed burning powder will solve all of your problems. Modern powders are too fast and snappy for P08. Off shelf ammo being loaded with very fast BR powders are not ideal food for P08s. Reason for that is to ensure proper functioning of majority carry weapons on today's USA market. Most of them have pipes less than 10 cm long. Nitrocellulose based powders from the beginning of the 20ieth century were not fast BR powders.

Hi,

What you say here is one of the secrets of getting a Luger to function properly.

Unfortunately, few people know about this, or, if they do, are willing to believe it.


Sieger

[SIGP2101]

Originally Posted by Sieger

Hi,



Unfortunately, few people either know about this,...
Sieger

That is the problem, then they start playing with springs, modifying them, exchanging them, replacing them. Then they sell it to the next person and fiddling continues.

Only way to modify P08 to digest modern ammo would be to some how magically increase overall mass of the breach or move forward the point where rear toggle link links with 'S' link . Moving this point forward by even a fraction of a mm would tremendously decrease cycling rate of toggle train.
Increasing or decreasing spring preload will lead only to premature wear and tear of various parts.

[John Sabato]

Originally Posted by Michael Zeleny

No flaws anywhere to be seen; lock open is sporadic.

With the upper removed, and the sear bar removed does the toggle move smoothly for the full length of its travel? or is there any hesitation or roughness?

Failure to lock open with only one round in the chamber and an empty magazine inserted indicates either a holdopen that has restricted movement (rubbing on the right grip), or that the mainspring force is too heavy. This is the first problem you need to solve before delving into magazine/feeding issues.

1. Check that the magazine button has no rubbing issues at the top of its travel in an empty magazine.

2. Check that the right grip is not preventing the magazine button from moving to the full up position because it is improperly inletted on the inside, or may be slightly oversize on the inside as a bakelite mold error, causing friction and preventing the holdopen from restraining the slide when firing that single round. You can test this by removing the upper and inserting an empty magazine and watching the holdopen. If it hesitates, even a little, it is rubbing the grip. There should be full motion of the holdopen doing this exercise with the right grip removed. The action should be identical with the right grip installed.

3. Install the mainspring from your LP.08 and see how that affects operation. The same results? or not?

4. Obtain an aftermarket mainspring from Wolff that is 16 LBs or less, and start removing approximately a half turn of spring one snip at a time until you are functioning with 115 Winchester White Box. Do this until you achieve lock open 100% of the time.

Anxious to hear how this exercise plays out...

[kurusu]

Originally Posted by John Sabato

Failure to lock open with only one round in the chamber and an empty magazine inserted indicates either a holdopen that has restricted movement (rubbing on the right grip), or that the mainspring force is too heavy.

Sporadic failure to lock open with Winchester ammo is not uncommon. I only had 99% lock open when I used Portuguese military grade ammo.

[Augsburger]

Thanks for this John. It helped me solve a cycling prob with my 1920 .30 cal commercial.

[kurusu]

Originally Posted by SIGP2101

That is the problem, then they start playing with springs, modifying them, exchanging them, replacing them. Then they sell it to the next person and fiddling continues.

Only way to modify P08 to digest modern ammo would be to some how magically increase overall mass of the breach or move forward the point where rear toggle link links with 'S' link . Moving this point forward by even a fraction of a mm would tremendously decrease cycling rate of toggle train.
Increasing or decreasing spring preload will lead only to premature wear and tear of various parts.

I beg to differ. Both my P08s ( BYF 41 and a 1915 DWM) work without problems with current ammo ( Winchester White box; Magtech and Geco) and with my reloads with slower powders (VV N340 and Vectan BA9).
I believe they both still have their original springs.

[SIGP2101]

Originally Posted by kurusu

I beg to differ. Both my P08s ( BYF 41 and a 1915 DWM) work without problems with current ammo ( Winchester White box; Magtech and Geco) and with my reloads with slower powders (VV N340 and Vectan BA9).
I believe they both still have their original springs.

I believe you. I had same experience with few P08 myself. Lots of them work flawlessly but topics is about stubborn ones and how to make them work.
Another important aspect is OAL. My experience with WWB is that is not consistent from box to box.

[Sieger]

Originally Posted by kurusu

I beg to differ. Both my P08s ( BYF 41 and a 1915 DWM) work without problems with current ammo ( Winchester White box; Magtech and Geco) and with my reloads with slower powders (VV N340 and Vectan BA9).
I believe they both still have their original springs.

Hi,

For a perfect fast powder target load, that works every time, try the following:

WW Commercial Cases
Remington 1 1/2 Primers
Hornady 124 gr FMJRN
Bullseye 3.7 grains
Cartridge Overall Length 1.173 inches

This is a fantastic target load, but it is a light one, less than 1,000 fps. On normal occasions, with hand held over a sandbag, up to seven have touched on a 25 yard target.

If you HAVE TO shoot fast powder, this load is an excellent one to use. Higher powder charges with this powder will cause both wider groups and cause jams.

The Winchester White Box, for me anyway, is not accurate in a Luger, as it throws bullets all over the paper at 25 yards, whereas, my carefully crafted handloads will put all eight in the 10 ring at 25 yards. Please search this section for a full listing of my most accurate handloads, if you like.

Just some of my experience with fast powders in a Luger.


Sieger

[Michael Zeleny]

Originally Posted by SIGP2101

That is the problem, then they start playing with springs, modifying them, exchanging them, replacing them. Then they sell it to the next person and fiddling continues.

Only way to modify P08 to digest modern ammo would be to some how magically increase overall mass of the breach or move forward the point where rear toggle link links with 'S' link . Moving this point forward by even a fraction of a mm would tremendously decrease cycling rate of toggle train.
Increasing or decreasing spring preload will lead only to premature wear and tear of various parts.

You don't need to increase the mass of the toggle train, provided that a heavy and/or long barrel is in place. An increase in the mass of the canon assembly generally suffices to delay the unlocking of the breech to the point of ensuring reliability.

[SIGP2101]

Originally Posted by Michael Zeleny

You don't need to increase the mass of the toggle train, provided that a heavy and/or long barrel is in place.

Right, but this is not your case judging by pic provided. My idea, was just to illustrate non feasibility of such undertake. We are talking about serious reengineering of ready made product. Keep searching for right ammo combination or get down to proper load and go from there. This will be the starting point with good indications if any other parts will have to be brought up to the right specs.
If you decide to go with heavier barrel you will be opening whole new can of worms.

[lugercollector]

I think the problem is with the feed ramp......when you cycle the Luger manually.....does it feed and eject properly?

[LugerVern]

Originally Posted by lugercollector

I think the problem is with the feed ramp......when you cycle the Luger manually.....does it feed and eject properly?

I played with this idea in the past, and it has some bases but may not be what your expecting.

A long time a go I had a perfectly functioning luger and as any gunsmith will tell you leaving your gun alone is next to impossible

I polished the feed ramp to a mirror smooth surface and then the problems with jams started, it wasn't until several hundred rounds later that it settled down and started functioning properly again.

As a new bullet goes up the ramp, a mirror smooth ramp allows the bullet to float and cause a jam. With some resistance the nose of the bullet is forced down and enters the chamber properly.

Seems strange but very true, lugers are very interesting guns

Vern

[SIGP2101]

Another way would be to install adjustable spring. There was a discussion about it while ago. Even patent drawing was provided. Then play with various tensions till desirable outcome is achieved.

[lugercollector]

I make and install barrels on Lugers here in Canada...The feed ramp angle is critical to proper function!!

[4 Scale]

Mike I'm sorry to read through this and see your persistent cycling issue.

I have two suggestions one of which you've likely considered:
1. Find a competent Luger gunsmith and have him look at it.
2. This may be nuts but - given your location in LA, contact a film school and see if they would be interested in filming the action of the pistol in extreme slow motion. Film school=cheap alternative. I'm taking classes at a film school in another state or I'd offer to help you myself on this. I would bet film students might be interested if you described the historical nature of these pistols and their "obsolete"/unique cycling action. Film school students love, love firearms in their short films due to the instant tension generated when an actor starts waving one around. Maybe you could trade use of the pistol as a prop in a student film for the slo-mo footage. Or try to locate some other resource to film the action in slow motion to see exactly what is happening.

Good luck, I admire your persistence. With enough effort you'll figure it out.