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Tips for Fitting the Flat Trigger


Skydiver

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I love this new trigger. It lets me position my finger more naturally. The pre-travel and over travel settings can be very finely configured. Removing the trigger and putting it back in is now a snap. Dry firing with it has been a wonderful experience. I’m looking forward to shooting it at my local match today.

I installed the trigger into my Elite Match .40 manufactured in 2009. The initial installation was dead easy. All the pieces in the kit fit in without needing to be modified. I’m not exactly mechanically inclined, but I figured out how to do this. After the installation, I had to fiddle around a little bit with fitting because my gun would reset properly only about 90% of the time. As you can imagine, I want a reliable reset for the sport we are into. On closer inspection, it seemed like there was a lot of pressure between the trigger bar and the plunger. I eventually solved the reset problem without having to resort to finding a stronger trigger reset spring.

Here are some tips for installing and fitting the trigger:

Watch the videos

Watching his installation video is well worth the download time. Looking at the parts and reading Henning web page alone had given me a really good idea of where the parts went and how to adjust things. Watching the videos, though, was even better because Henning would drop little tips like using a greasy oil to hold the reset spring in the pocket. Additionally, watching a master at work, there are subtle things that I picked up like the technique he uses to slide the trigger bar and trigger back into the gun. To use a phrase I read elsewhere in the forums to describe what Henning does: “Nordic magic”.

Another way to temporarily retain the trigger reset spring: use a 3-48 set screw

As I was going through the fitting process, I had to take the trigger system in and out multiple times. If you are like me with clumsy fingers, using the greasy oil was making me even clumsier as I got more and more oil on hands and fingers and parts. For a little while, I changed over to Slide Glide, but that was still getting a little messy. My solution was to temporarily replace the over travel screw with the set screw from my H-550 base pads. The threads on the set screw do a good job of keeping the spring from falling/flying. Remember to swap out the set screw and put in the real over travel screw when it’s time to figure out the over travel setting.

Inspect the plunger surface

The surface of the plunger that pushes up on the trigger bar should have four triangular facets like a smooth flattened pyramid. Strangely, the surface on my plunger seemed to have only two rectangular facets. This was from the factory and I’d only polished it and not changed its shape. When I swapped in a factory plunger with the four facets borrowed from my Match .45 the reset suddenly got a lot more reliable. I eventually ended up re-shaping the “bad” plunger surface with a stone and file to mimic the working plunger. After reshaping, I polished everything back up again. I imagine that the number of facets decreases the surface contact area and therefore reducing friction.

After talking to Henning, it sounds like he’s following up with Huening about a roller design for the plunger.

Check trigger bar contact with the hammer

You may have to file down the part of the trigger bar if it comes into contact with the hammer. After my sear problems (see old post), I replaced my factory sear with the EGW sear and hammer. I noticed that the trigger pulled and as I was cocking the hammer manually, the trigger bar was being pushed down. When I removed the sear cage, it became pretty obvious where part of the hammer was rubbing on trigger bar. This is because the EGW hammer has more material in front of the hooks as compared to the factory hammer.

I had a choice between filing down that contact area on the trigger bar or on the hammer. Since the new trigger system was built for easy installation and removal, versus having to knock out roll pins on a Witness Match to get a hammer out, the choice was very easy. Did I mention that the trigger design rocks?

Check trigger bar contact with the sear reset leg

I’ll admit that this tip is probably overboard and my solution may not be the best one. I was already getting reliable resets with the plunger fix and filing down a little bit of the rear end of the trigger bar.

On my gun, the sear reset leg on the EGW sear was thick enough to also push the trigger bar down when it sits on a ledge on the trigger bar. This is by design since the trigger bar needs to slide forward and popup in front of the leg when the trigger is reset.

I felt that I could help the trigger reset by changing the flat ledge into a very shallow polished ramp so that at best it’ll encourage the trigger bar to move forward, and at worse the trigger bar would be pushed down by a fraction of a millimeter less than before. Let me re-emphasize the very shallow part. I wanted the original design where the trigger bar needs to popup before the sear can be activated again. I didn’t want to create an ultra short reset due to the reset leg catching on the ramp.

A (better) alternative may have been to make the reset leg thinner to let the trigger bar come up a little bit more, but still keep the popup design.

Check plunger function

Make sure that the plunger compresses and decompresses smoothly. I ended up polishing the center post of the plunger just because I could, but I doubt that this is really needed given the very short compression distances the plunger goes through for normal trigger operation.

(As an aside: If somebody knows how to seed a BitTorrent for the huge video downloads, that would probably help with the huge downloads. This is assuming that Henning, as copyright holder, gives permission to redistribute by BitTorrent.)

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I love this new trigger. It lets me position my finger more naturally. The pre-travel and over travel settings can be very finely configured. Removing the trigger and putting it back in is now a snap. Dry firing with it has been a wonderful experience. I’m looking forward to shooting it at my local match today.

The trigger worked very well today. I wish I could say the same about the shooter pulling the trigger. :-)

The trigger pull was super smooth with a nice consistent crisp break.

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I installed my new flat trigger last night but it did not go as smooth as yours did. I put it on my 10mm Witness Match which I bought about a year ago. The new trigger was very tight, so much that to get it in there I had to remove some material. I know the main purpose here is to have a tight fit so I would file very lightly and check the fit each time. Once I got it in the gun I then had the problem of the pin being to large to go through the frame. I opened up the hole with a 3/32nd bit which allowed it to go through but still with a tight fit. Once the pin was through the frame and trigger I then had the problem of it binding up which resulted in great force to operate the trigger. Later on I did call Henning and he indicated that the pin should have been polished and not rough like it was. After polishing and a little more fitting I finally had a new working trigger but with one problem. Like you had stated what happened to you I had the problem of the trigger not resetting. After close inspection I also saw that the trigger bar was dragging on the plunger. I pulled it back apart and found that the notch where the plunger rides up in on the bar was very, very rough. Got out the dremel and polished that area up the best I could and re-installed.

After many dry fires I will still get the occasional failure to reset but nothing like before. I think I will probably polish the top of the plunger also just to be safe. I also believe that probably after a few rounds it will probably go away anyway. This trigger is what I had been waiting for as I often had to re-postion my hand after clicking the safety off to reach around and pull the trigger. Going to try it tomorrow night in our weekly IDPA match

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I'll add another tip to this thread. The sear arm that is pushed by the trigger bar can be trimmed and thinned to help shorten reset and move the trigger reset back farther. With my stock trigger, the previous owner was very agressive trimming the sear arm. The result was a nice trigger with a short reset. However, with the new Henning trigger, the bar was not long enough to fully trip the sear. The trigger actually bottomed out on the frame before the hammer would fall.

I had two possible solutions. One was to buy and fit a new sear with the untrimmed arm. The other was to increase the reach of the trigger bar.

Luckily, I had a friend with a TIG welder. He is very good and added a bead of metal onto the trigger bar right in the spot where it pushes the sear. I spent a few minutes with a file and stone, and the result is an additional 80/1000" of material, and a new trigger that now trips the sear.

My trigger now is a little forward of veticle, but seems to fit my hand well. If I want to move the trigger back, all I have to do is remove a little more material from the bar.

Maybe if Henning designs a new trigger bar, he could add an adjustable pull length!

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I pulled it back apart and found that the notch where the plunger rides up in on the bar was very, very rough. Got out the dremel and polished that area up the best I could and re-installed.

You probably figured this out on your own. My first Witness, a Match .45 had the same rough area. What I did to smooth that out was to sand down the area. I cut a strip of 400 and 600 sandpaper as wide as the notch. Then using the plunger as a backing support for the sandpaper, I first ran the 400 grit paper to get the high spots, then the 600 to smooth everything out, and finally the Dremel polishing wheel to get everything nice and shiny.

Good luck at your IDPA match!

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I've had mine in and out probably 4 times so far and I haven't sworn or thrown anything across the room like I did with the stock set up... That's worth the money right there. Really, I think you will be more than happy with the ease of install and adjustability.

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for those of you that have the new trigger (I have one on the way)...whats the general consensus? Worth the money?

YES! Even with the troubles I had with my sear and trigger bar (most people won't have this problem) I would buy again.

My favorite things about this trigger:

1. Tighter fit. My old trigger used to wobble around side-to-side a lot. The new trigger is much tighter with less wobble.

2. Ease of installation. No silly spring to drop or loose.

3. No more stupid roll pin! I really like the new threaded pin.

4. feels better to shoot, with closer pre-travel and over-travel.

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Keep in mind that if you have already done a trigger job on your gun that has the stock trigger far back in the trigger guard, you will probably have to get a new sear when installing the Henning flat trigger kit.

I have cut the EGW sear leg back on my gun to have the stock trigger very far back in the trigger guard and when I installed the Henning Flat trigger the trigger bar wouldn’t even touch the sear leg when the trigger was fully pushed back. I have to use a new EGW sear to use the Henning Flat Trigger on my gun. This isn’t a bad thing against Henning’s Flat Trigger design, it does place the trigger bar in its “Stock” location for engaging the sear leg. But if you have cut back the sear leg to move the stock trigger back within the trigger guard you may have issues when dropping in the Henning Trigger kit. That’s just part of how it goes when modifying pistols.

I wanted to make this known to the guys installing the new Henning Flat trigger as it might save them some time to order another EGW sear along with their Flat Trigger kit because it may be needed depending on the prior trigger job that was done. It sucks to have your new flat trigger kit half installed only to find that you don’t have all of the parts you need to complete the change from the stock to flat trigger. If you have the extra $$$ hedge your bets and order another EGW sear along with the Flat Trigger kit.

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When the long trigger comes out I will be getting a new sear/hammer combo at the same time.

I have had a few cases of hammer-follow over the past few months so I suspect that the sear has finally given out. It's the stock parts and they've been there for 2.5 years.

I already have the new hammer pins installed and a trigger/hammer/sear update should last me for years to come.

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What Charlie says is one of those design issues I had to grapple with when we came to a final stage of the trigger. Because of the way the spring is held in place it can only move so far back before it bottoms out (spring cap part of trigger meets the frame).

My sear leg has been shortened as well, but probably not as aggressive as Charlie's. I had one sear that almost had no sear leg and I wasn't able to use it with my trigger. I would recommend using the "EGW prepped sear" as it comes without modifying it. That will put the trigger in the best position.

Of course... now we just have to design and make a new trigger bar that has length adjustment in it. That way you could fully tune the trigger to be at perfect 90 degrees. I've got a few other projects on the burner, but it's just gotta be made..

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I installed the new flat trigger last night. All parts dropped in without a fuss. This is on a brand new unfired Limited 40 with the stock hammer/sear. No fitment issue at all...very nice piece!

After taking the trigger in/out of the frame about 5 times to adjust the pretravel I finally had it perfect. Very little trigger pretravel movement, clean break, tight fit. Over travel was very simple to adjust while trigger was in frame. Now when manually cocking the hammer (slide off) the trigger would reset 100% of the time. I also had zero hammer/sear interference when cocking the hammer with the trigger pulled back. When I decided all was set I put the slide back on the frame to give it a try. When manually racking the slide back the trigger would not reset at all. I would have to manually push the trigger toward the muzzle to reset it every time. When cocking the hammer manually with my thumb it WOULD reset 100%. Why would this be? What would cause the difference between manually coking the hammer and letting the slide cock the hammer? I thought maybe I had pretravel too tight so I even went back in and removed the pretravel screw all together but got the same result. It almost seems like the trigger return spring is too weak to push the trigger back into the reset position. I am quite the novice with these things so any help would be appreciated.

FYI - I polished and smoothed the trigger bar/plunger interface and there doesnt seem to be too much pressure there.

Edited by jmleenz
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Jeremy

The return spring is fairly light and a heavier spring may fix it. However it would just mask an underlying roughness somewhere. Try to take all the parts out and play with it some more. I've got a few left of the 0.018" music wire and I threw one in your package I'm sending you today along with your new grip.

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FYI - I polished and smoothed the trigger bar/plunger interface and there doesnt seem to be too much pressure there.

I think there is supposed to be pressure from the plunger on the trigger bar. It's what keeps the trigger bar in the right place. I think if any metal is removed from the plunger then the bar could sit lower than it should and then the reset may not work. Just a thought.

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OK well my best advice here is if it doesnt work the first time try, try, and try again. After taking it in an out a few more times adjusting, inpecting, etc it somehow now resets! Dont know what changed but it resets now everytime. Tinkering was the solution I guess lol. I adjusted the pretravel to almost nothing. The overtravel is where I wish I could tighten up a bit more. Im on the very edge of overtravel adjustment, anymore and the sear starts rubbing against the hammer. Im guessing the EGW sear/hammer would reduce this further but any way you slice it its a heck of a lot better than stock! The gun hasnt even been shot yet so Ill get back in there after a thousand rounds and see if anything loosens up. Pics coming!

BritinUSA - there was definetely pressure between the plunger/trigger bar there but not enough to be causing so much friction there it was preventing reset.

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In my opinion and probably many here feel the same... the factory trigger plunger and bar is "rough" at best. A precision made plunger and bar would be a big advantage. Huening has hinted he will start making the roller head again. It would be a great improvement for trigger weight and smoothing out the trigger action. I hope he makes it. If he doesn't I'll give it a go. I have a lighter trigger plunger spring that I've had made (sample springs) which I felt helped in reducing trigger weight and unnecessary pressure.

Both plunger and bar vary in size, fit and function. When usng factory parts everything is "sloppy" so it works as planned, but when you are really trying to produce a precise trigger every factor plays in. Just "playing" with the trigger as you put it will help and my install videos shows some of that as well.

When I did the R&D on the trigger I had 3 different return springs made; a 0.014" a 0.016" and a 0.018" music wire made. All same OD and length The 14 was too weak and acted as you described. The 18 was too strong for my taste. The 16 was to date never failed me and gives a light, yet reliable return. It however is likely that rough spots and the fact that the trigger performs precise puts a challenge on other components such as the trigger plunger and bar.

I pondered having a 17 and/or 18 produced as an option in case of difficulties like you mention. But my feeling is that it would be a compromise over trying to get all the other parts fitted nicely.

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With the way the trigger bar sits on the plunger in my gun, I wish I could bore or counter-sink the hole on top of the plunger to the right size and depth, and drop in a ball bearing. Think of the tip of a ballpoint pen, or a roll-on dispenser, but the ball is free to pop out. The trigger bar itself would keep the ball bearing from popping out and in theory the only point of contact between the trigger bar and the ball will be a single point. If done right the ball will rotate freely inside the slot. Even if the ball didn't rotate freely in the plunger, a single point should be a lot less friction as compared to two almost similarly shaped curved surfaces rubbing against each other.

I wonder if a Telflon ball bearing would even be better than a steel ball bearing since Teflon has a lower coefficient of friction. Teflon against Teflon has even yet a lower coefficient of friction.

Hmmm... McMaster-Carr has Teflon balls, as well as Teflon tape with adhesive backs... Hmmm... Put tape in the channel under the trigger bar and the ball in an appropriately prepared plunger. May have to trim some coils on the plunger spring to compensate for the added thickness of the tape and exposed ball.

Any thoughts from engineering minded people about this setup?

Edited by Skydiver
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