Trigger job?
 

Folks, I'm new here, I recently bought a 1913 DMW Luger, the numbers are not matching and it was in a relatively bad shape, so I decided to practice my restoration skills on it and use it as a shooter. I detail stripped it, removed the old paint (yes, somebody sprayed black paint all over it), cleaned it up and rebelled, now it looks pretty good now but the trigger pull is awful. It is very gritty and long. So I'm wondering what is the best way to improve it? Doesn't have to be light, but I'd like it to be smoother. What is the proper way to address this?

I know the trigger system in a luger is complicated. There should be some insight here in this website. Take a look around.

J Duke, For a shorter trigger pull, you will have to reduce the overlap of the striker and sear. Also flattening out the flat sear spring will lighten the force required. Unfortunately, taking either of these steps too far may lead to the pistol wanting to go full auto. TH

Your Luger may well have the wrong trigger return spring installed(too strong). Lugers do not have great, target trigger pulls, as many were war products. They can be improved, but go carefully for they can go full auto.

I'd clean it well and lube; then leave it alone.

There is not much upside to improving the trigger, and lots of "down" side. JMHO.

improving luger trigger
 

here is an article that I saw in a shooting magazine years ago
Ray in Oregon

*** Mod Addition *** High Resolution PDF is in post 18 Below ***

*** See Below for PDF copy in High Resolution *** And accept the caveat that the author didn't have the correct reverse angle information Don discusses below.

- - - - - -

In spite of the good information in the article, Luger trigger adjustment is as much an art as anything else, and that art is likely based on some experience.

As Don says, we hear much more often about problems caused than improvement achieved.

Most everything in the complete linkage affects other parts, some of which are covered during operation.

Great write up, BUT- the reverse angles that give the luger a heavy trigger pull are necessary for the sear and striker to firmly and safely engage- messing with the angles and amount of engagement is asking for :
a- failure to ****Kyock
b- doubling
c- full auto fire
d- unexpected discharge without touching the trigger!

Amen to what's been said. I've had two Lugers fire upon toggle closure (finger not on trigger)- not a fun experience! I didn't do anything to these triggers, but I suspect the previous owner(s) did.

I agree completely with Don, leave it as it is.

This was my immediate observation as well. Interestingly, the author states that he has observed this "flaw" in every Luger he has examined, and he still doesn't understand that it's made like that on purpose. BTW: The same "flaw" can be found in mil spec AR-15 triggers, and people are still trying to "correct it" with the same results as you mention.

What leads to the need for the negative sear engagement?

How much is it (angle?)

Is this because of the potential for "bounce" of the slide when it comes back into battery after firing a shot? Or is it needed to draw the sear and firing pin together when it comes into battery?

Why is the single stage AR-15 designed with this engagement?

I think a description of the thinking behind the negative sear engagement would make a good FAQ entry... Marc

Ray, if you can get higher resolution scans of the article to me, I'll make it into a PDF file.

Marc

My first 1911 had a trigger pull that felt like dragging a knife blade over rough concrete. The 1911 sear is case hardened maybe 1/1000 inch thick is hard. But examination under magnification showed manufacturing burrs, removing them (fine Arkansas stone) made a nice trigger.

I would limit any trigger work to similar smoothing. Changing angles is extremely risky, and best done with easily replaceable parts (Oops, start again), not Luger fitted and numbered parts.

Marc,
I have that trigger tune article in .jpg format that is pretty legible and I can save the pages in .png format if that would be better. Either format can be expanded.
Ron

Of my four, only my refinished LP-08 has a clearly noticeable trigger "wall" before the break. The others are a bit mushy with takeup and are difficult to get a grasp on where the sear will "break". I do not worry about it too much since they do not malfunction, and it isn't like I am using them for anything other than as range toys or safe queens.

See comments above.

Out of curiosity I examined the firing pins of my 2 last night.
Under an 8x Loupe both had crud on the surface engaged by the sear.
Crud being microscopic bits of either metal or powder stuck to the surface with oil.
Actually looked more like fine metal filings (not me) than powder

A toothbrush and cleaning patch.
Unfortunately I am in a lockdown State and cannot field test the result at this time

Ron was good enough to provide high resolution scans of the article. I've attached it here.

Marc

What I like about that article is that several times the author admonishes the reader to fully understand the firing mechanism before attempting any improvements. If that advice is followed and the pistol's operation observed carefully it should be possible to determine what might be causing the poor trigger performance.

I would suggest complete disassembly (including removal of the sear bar and transfer lever), inspect (preferably with magnification), clean lubricate then reassemble and test before attempting any physical adjustments. The only time I fiddle with trigger components is to correct malfunction. To me, getting good accuracy without resorting to physical modification is part of the fun and challenge of firing older firearms.

I when I find myself missing nice triggers I shoot modern pistols.

Luger triggers are no worse than an out of the box Glock, or one of the other DAO pistols, IMO.
Many are somewhat better!

I agree with Don. And the proof of the pudding is "did you hit what you were pointing at". The Luger is pretty good at that; the grip and balance making up for the trigger issues.

I've never adjusted a Luger trigger, but this discussion got me curious about what's been documented. So... I've been searching around about sear engagement, and found many and varied discussions about it.

for the AR-15, this one seems reasonable:

https://www.ar-15lowerreceivers.com/...oubleshooting/

I also pulled the blueprints for the Luger, and the firing pin shows about a 2 degree angle from 90 degrees off the plane of the firing pin's side. The angle is 2 degrees offset from 90 toward the rear of the firing pin, and at a right angle with the angled portion of the rear of the firing pin it intersects.

It's on page 14 of the blueprints published and sold by John Sabato, so I don't want to reproduce them without his permission.

The sear bar itself seems to have a zero degree offset. It's on page 13 of the blueprints. Since it is rotated around it's fulcrum point when the gun is in battery, I suspect that it's at about a 2 degree angle from the plane of the side of the receiver. If so, it would meet the firing pin's surface straight on at a zero degree angle (no positive or negative engagement).

Sturgess discusses changes to the sear engagement and sear lever design during prototype work, but it's not specific except to say that the sear lever was lengthened "to give an easier and smoother pull off".

On page 382, he discussed a very rare Swiss manual published in 1948 on adjustment of the Luger trigger. It describes a means of bending of the sear bar for adjustment (???) because grinding material to adjust engagement with the firing pin is forbidden. Bending apparently worked with sear bars marked "Chrome Nickle" but that great care should be taken with others because of brittleness.

Less than 175 copies of this trigger adjustment manual were known to be made, and the illustrations in Sturgess are very small, and only a small number of pages.