If that's true, then what also must be true?

[G.T.]

I must admit, my approach to repairing Lugers and Luger accessiories has a bit of Monty Python philosophy mixed in, and I believe it helps keep me sane because I cannot explain how I got to the results I desired, and what I did to be successful along the way....
Making the fire control parts on a Luger work as designed is one of these enigmas that I find more a matter of luck than skill?
Anyway, I have set in my own mind some things that have to happen, and some that absolutely must NOT happen to make a Luger safe and dependable for target and range shooting!
First, the issue, one of two things... A luger that has been tuned for a target, (light pull) trigger, and second, a Luger, probably miss-match, that doesn't disconnect properly and you can't, won't get a second or follow up shot?
For either issue, you need to check out, first, the major assemblies, basically the top half, and the bottom half. There are some components of the one, that influence the other, but by and large, certain things have to be correct in each assembly before you can't mate the two with some certainty of success?
Let's start with the frame side plate assembly. Here's what has to happen, the side plate must be installed properly and matched to the frame, matching numbers or not, it has to be tight, square and along with the trigger lever, needs to do the following. When letting up on the trigger all the way, the top end of the trigger lever goes back into the side plate. It must retract back far enough to allow for the disconnector to snap past when the receiver comes back into battery and you then release the trigger.... On the other end of the spectrum, the trigger lever end that impinges on the disconnector pin after reset, should come to be square the the edge of the side plate when the trigger is almost stopped at the frame. If you are following my thoughts closely, you are probably saying to yourself, that's a lot of trigger travel for what I need/want it to do? It is DESIGNED that way!
Keep in mind, the closer the trigger travel that occurs between the sear break and disconnect reset, the closer you have to shooting a Luger machine pistol... All you 4 pound trigger guys pay attention!
Ok, we've caused enough trouble with the frame assembly, lets move to the top half. Here is the major tells on correct function of the firing pin / sear bar combination. First, check the sear engagement surfaces on the sear bar and firing pin, neither should be rounded or at any wear angle other that 90 degrees, the more engagement the better. The forward top leading edge of the sear bar should not protrude beyond the edge of the protective shelf above it, and, (be careful here!) can be adjusted by slightly bending the back end ot the sear bar where the sear bar spring sits! Remember!!!! This will affect your sear surface engagement as well... This is what tuning is all about, very little adjustment, makes a lot of difference at the other end... The sear bar adjustment, also has the effect of bringing the disconnector pin closer to the receiver and allowing it to better clear the trigger lever when the trigger is released? Thus enabling the frame fire control parts to better function in the range that is desirable? Now, we've pretty much worked on our Luger for several hours and accomplished very little? Why you might ask, and the reason is, probably, we have not taken into account that the receiver and frame are a "sloppy" fit, and the excessive tolerances created by this are skewing all our efforts up to this point... OK, if you get to this point, all you can do going forward, is throw parts at it? Sooner or later the correct part, (most of the time side plate, more of the time trigger lever), and you'll get it working...
I thought I would share this with the forum before I forget what I know ..... BTW, all of the above is just me, some have better luck, some worse, this is just what it took fo me to get by! Best to all, til.....lat'r.....GT....