What is a 'good' trigger pull?

[TennBill2]

I pose the question with my 'Borchardt' project in mind. I'm of the opinion the Luger and Borchardt fire essentially the same. I had been working on getting the right firing pin tension. I discovered I had an abominable trigger pull.......as in pull as hard as I could! Looking at the blueprint drawings(Luger) of the sear bar, I increased the angle a tiny bit. Voila', I now had a 'hair trigger'. "That's not good", said I. Back to the grinding wheel! With a 'safe' file, I took a thou, or so, deepening the depth of the striker's retaining notch, but not changing the angle. Wow! as luck would have it, I wound up with what I consider a perfect trigger, firm but not heavy. How does one measure trigger pull? I suspect there must be 'tried and true' methods for tuning a standard Luger pull, what ever that might be. My two 'off the shelf' Lugers handle fine. But I guess replacing a striker, or sear bar may upset the balance of things. Bill

[Michael Zeleny]

On the Lyman electronic trigger gauge, the trigger of a heavy frame SIG P210, serial number P79608, yields a weight of 1.2kg, averaged over 10 pulls. That's about as good as you can get in a tuned service grade self-loading pistol. More typical are the measurements of Borchardt C93, serial number 1774, releasing the striker at 2.59kg, and Krieghoff P08, serial number 3249, weighing in at 3.48kg. I will get back shortly with the numbers of two W+F tuned 06/29 National Match Swiss Lugers.

[TennBill2]

Thanks, Michael. Interesting that there is data of any sort on the Borchardt. I'm not familiar with the Lyman guage and I don't readily know how to convert to oz./pounds but will look up in a minute on a conversion chart. I found, too, I had to get the tip of the trigger 'tripper' tip exactly right also. It had to have a slight angle, fore and aft, and a kind of 'ski slope' angle for the 'roller' to rest on. Such that the action works together smoothly. I would have to guess each original must have had a considerable amount of hand work done to work well. I read, for example, in Walter's 'Luger Book', each gun had to be matched at the factory (the mainspring) to the particular batch of ammo. I noticed by the 30's, ammo was being labled for the 'Mauser and Borchardt', probably wasn't the best thing for the Borchardt.....explaining, perhaps, why I've read they had a terrible recoil.

[sheepherder]

Originally Posted by TennBill2

Thanks, Michael. Interesting that there is data of any sort on the Borchardt...

Michael owns a Borchardt (maybe more than one). He's measuring his.

I usually aim for 4 3/4# pull on my handguns. I use an old electricians electric motor armature brush gauge. Entirely mechanical. None of this new-age electronic rubbish.

[Michael Zeleny]

I made all of the foregoing measurements myself. The averaging capacity of the Lyman gauge comes in very handy. Potentially more helpful would be the computerized trigger and spring analysis afforded by the TriggerScan system, as used by Veit Morgenroth with results recounted in his book Willi Korth -- Seine Waffen.

[TennBill2]

Couldn't find my fish scale.......so, I turned on my electronic postal scale and tried to 'guesstimate' with my 'trigger' finger. I figure I'm at about 2.5-3lbs. Feels quite nice to me! And, Postino, I'm assuming your including Lugers in the 4 3/4lb figure. So, what's your method for fine tuning the Luger arrangement?

[sheepherder]

Originally Posted by TennBill2

Couldn't find my fish scale...

Hmmm...Never thought of that!

...Postino, I'm assuming your including Lugers in the 4 3/4lb figure. So, what's your method for fine tuning the Luger arrangement?

No; no Lugers...never even measured mine...wait one...My commercial 7.65 and my 1937 S/42 both break at 6#...I've never tried to tune them...

BTW: My gauge is a Martindale...Left over from my millwright days...

[Michael Zeleny]

Swiss Lugers had their triggers tuned with an armorer's tool made and sold by W+F.




The photo shows four lots from the Kessler auction of 6 November 2010:

• 29427 WES Pistole, CH-Ord. Parabellum 29, Kal. 7,65 Para. Nationalmannschaftsmodell mit dickerem, 170mm langem Lauf. S/N 59951 Vergl.: Rutsch, "Faustfeuerwaffen der Eidgenossen", Seite 266ff, mit einer Abbildung genau dieser Pistole.
  Sfr. 2500/5000.- siehe Abb. Zustand: neuwertig | Sfr. 12000
• 29428 WES Pistole, CH-Ord. Parabellum 29, Kal. 7,65 Para. Nationalmannschaftsmodell mit leichtem, 200mm langem Lauf. S/N 65721 Vergl.: Rutsch, "Faustfeuerwaffen der Eidgenossen", Seite 268ff, mit einer Abbildung genau dieser Pistole.
  Sfr. 2500/5000.- siehe Abb. Zustand: neuwertig | SFr 13000
• 29429 Abzugsstangen-Richtgerät, CH-Ord. zu Parabellum Pistolen, damit können ungehärtete Abzugswinkelhebel zur Regulierung des Druckpunkts gebogen werden.
  Sfr. 400/800.- siehe Abb. Zustand: 1 | SFr 950
• 29430 Kornschieber zu Schweizer Parabellum-Pistolen.
  Sfr. 100/200.- siehe Abb. Zustand: neuwertig | SFr 220

The armorer's tool of Lot 29429 allows precise regulation of the double pull trigger sustem. The trigger lever is annealed, bent to ensure an optimal clearance in its engagement with the sear, and hardened anew.

I will provide additional information about these items next week.

[TennBill2]

If I did this correctly, the Luger would have a pull of 7lbs,10.75 oz. The Borchardt: 5lbs, 11 oz.!

[TennBill2]

Really great academic info, Michael! Never saw these tools before. Ever think of writing the 'Complete Book of the Borchardt-Luger'?

[Michael Zeleny]

I am composing technical studies of the SIG P210 and the Manurhin MR73. Countless others are far better qualified to analyze the workings of the Borchardt-Luger.

[G.T.]

Hi to all, there's a lot more to a good repeatable trigger pull then just weight, also important are take up, slack, creep, break(as in crisp & uniform), over travel along with sear break weight... it's not just the pounds of pull on a luger trigger, it's all the rest as well... Of course, one is certainly limited by very expensive replacement parts, and hard to modify parts as well... Plus on top of all that, the design doesn't really lend itself to modification very well, as there is plenty of "In & out" as well as "back & forth" to contend with... As a result, I think in general, we've ended up with a lot more machine pistols then improved triggers..at least for the first few go arounds!... Best to all, til...lat'r....GT

[Michael Zeleny]

Originally Posted by G.T.

Hi to all, there's a lot more to a good repeatable trigger pull then just weight, also important are take up, slack, creep, break(as in crisp & uniform), over travel along with sear break weight... it's not just the pounds of pull on a luger trigger, it's all the rest as well...

All the rest is measured by the TriggerScan system. I suggest looking at the previously referenced study of Korth firearms by Veit Morgenroth for examples of its output.

Of course, one is certainly limited by very expensive replacement parts, and hard to modify parts as well... Plus on top of all that, the design doesn't really lend itself to modification very well, as there is plenty of "In & out" as well as "back & forth" to contend with...

I don't buy these cavils in view of W+F having managed to reduce "In & out" and "back & forth" well enough to win the 1949 ISSF World Championship. I further submit that a properly tuned two-stage Luger trigger will have a much crisper sear engagement than a similarly prepared single-stage M1911.

[G.T.]

Well Michael, I love lugers as much or more then the next guy... But I learned very early on that they were never designed, or intended to have match grade sights, and target triggers... And yes, a few have been successfully converted, and a few have even won in tough competition..... I'm even trying to build one myself, like I said, I love'em!!.. But, that puts Lugers solidly in about the .0009 percentile (If even that??) of winning guns in the tens, maybe hundreds of thousands of pistol matches shot over the last seventy five years... .....Also, I have experienced that when a competitor is backed by a factory... his chances are markedly improved... I think the reason you see a lot of 1911 types shooting in competition, is because they work well for it, and people win with them... Simple as that, If the Luger held the magic at the contest, they'd all be shooting them...
And sometimes, right guy, right gun, it's just your day.. I've seen excellent pistol shots, and it really didn't matter what they shot, as long as there were some sights and the trigger wasn't welded solid... (I think they could still beat me with those handicaps...)... So, I guess I respectfully disagree with the notion that the Luger in any form, will compete with a match grade 1911, probably on any level, with the exception of perhaps the WW battlefields, I don't think the German Army, in the whole of (both) war(s), had as many stoppages and failures to feed as we peacetime shooters do! ... .. Best to all, til...lat'r...GT

[Olle]

Originally Posted by G.T.

Hi to all, there's a lot more to a good repeatable trigger pull then just weight, also important are take up, slack, creep, break(as in crisp & uniform), over travel along with sear break weight... it's not just the pounds of pull on a luger trigger, it's all the rest as well... Of course, one is certainly limited by very expensive replacement parts, and hard to modify parts as well... Plus on top of all that, the design doesn't really lend itself to modification very well, as there is plenty of "In & out" as well as "back & forth" to contend with... As a result, I think in general, we've ended up with a lot more machine pistols then improved triggers..at least for the first few go arounds!... Best to all, til...lat'r....GT

I have done a few trigger jobs myself, and I agree. There's good trigger pull and there's safe trigger pull, but what you want is a good, safe trigger pull. I usually work with more modern guns with way simpler trigger mechanisms, but have still managed to create some full-auto pistols and rifles by being careless with the honing stone. It's no fun having to buy new parts and start over just because you didn't do your homework.

You would think that the sear is most important, but that's not always the case and it's usually the last thing I look at. A slick trigger pull feels much lighter than what the gauge may tell you, and you can get a very nice (and safe) pull by just polishing all the bearing surfaces, pins etc. In some pistols I have found that the greatest improvement was after polishing the sides of the hammer and the sear. In short: Polishing anything that can rub or bind is a safe way to improve the trigger. Changing spring weights can also make a great difference. Lugers and Borchards are of course totally different animals, but the same principles should apply.

[G.T.]

Hi ollie, I agree, polish and springs could make the most dramatic improvement, with out sacrificing safety... Any time you start grinding.. well, let's just say, A lot of other things have to be right first... ... Best to all, til...lat'r...GT

[SIGP2101]

Just by polishing areas indicated in red to a mirror shine (without changing geometry) Luger trigger action can be improved significantly. (DO NOT USE DREMEL FOR THIS)

Second part would be to install travel adjustment screws. This can be done on trigger itself or sear bar. There are multiple locations for this.

Third step in improving Luger trigger feel is to eliminate wobble completely from the plunger. Maybe required to built entire new and longer plunger. Longer means it will have to be seated deeper in new drilled hole.

Anyone can accomplish first step and immediately benefit greatly improved trigger.

[luscioman]

I have found that changing the springs have proved to work out very well for me. The cost is not very high and you can easily change them back or mis-match them to what you like. I had a BYF-42 with pull that was too light that came out very nice with Wolff springs. I only have one shooter that is causing me an issue at this point.

[Michael Zeleny]

As measured with the Lyman electronic trigger gauge, averaged over 10 pulls:
Swiss 06/1929 SN 71644: 3.80kg
Swiss 06/1929 SN 77493: 2.57kg
Swiss 06/1929 National Match SN 59951: 2.64kg
Swiss 06/1929 National Match SN 65721: 2.15kg

[TennBill2]

Thanks, Michael for posting the data. Couple weeks ago, Olle came to my place and 'shot' my Borchardt replica....with only a primered shell. He described it as a 'light pull'. We didn't get around to using his gauge to actually measure the pull. perhaps another day we'll meaure my Lugers, etc. and I'll post the results. I like the feel of a light pull, why, too, I like set triggers! I think I'm less likely to pull the weapon off target then when firing with a heavy trigger. Bill