Installing the Huening Rolling Trigger Bar Plunger

[eastonx7]

Good morning Everyone!

Yesterday, while watching Hot Tub Time Machine, I decided to fit the Huening Rolling Trigger Bar Plunger to my wife's Eric Open. The process was a little more involved than anticipated, so I thought it would be a good idea to share my experience.

The first step I made was to drop the parts in to see and feel how everything fit. I noticed three things:

1) The Huening plunger spring was much lighter than the factory plunger spring; this was good because it confirmed the notion (mentioned in another post) that it was alright to lop off 1.5 - 2 coils from it. I opt to lop off 1.5 coils from the factory spring and use it with the Huening plunger. I wanted to keep the Huening spring as a backup.

2) The roller wasn't rolling! The Huening plunger housing was making contact with the trigger bar (that beautifully polished pocket that meets the factory trigger bar plunger - yes, yes, we all know it soooo very well); I shouldn't say making contact though, I should actually say scraping and grinding. This is where all the fitting occurred - for about 30 minutes.

I started the process by taking a small file and rounding out the edges that were making contact. Which edges, right? Well, because the underside of the trigger bar is beautifully polished to a mirror finish, I took red permanent felt marker and coloured all shiny surfaces. I dropped the parts back in and pulled the trigger a few times. The areas that didn't have red markings were friction points, and made it very easy to figure out which edges to round out.

After 10 minutes, I gave up and pulled out the big file - more affectionately known as the Dremel! Before I did this though, I punched out the roller's pin so I wouldn't damage it. It also gave me a better angle of engagement to work with. Because I was dealing with 4,500-5,000 rpm, the housing was a little too small to hand-hold - I like my fingertips the way they are; I ended up using a punch that fit nicely through the neck of the housing and held it in position with my thumb - giving me all the surface area necessary to do the work.

If you take a look a the picture below, you'll see the original (left) and the modified (right). Based on the way the housing fit to my wife's pistol and trigger bar, I needed to perform two modifications:

1) to round out the top edges - similar to the factory plunger's profile

2) taper the nose, to eliminate the contact that the housing made with the trigger bar - past the polished pocket

You'll notice that more of the roller has now been exposed and there's enough meat to the housing that will still keep the roller's pin in place.

Note: the profile I came up with may very well be different in your pistol, so do be careful with your modifications.

Once I finished shaping and polishing, there was only one modification left.

3) to polish the dowel that the spring and the roller's housing plunged upon. I simply took 600 grit sand paper and lightly polished the surface. I spun the dowel in a drill to be sure the shape did not change.

Well, by the end of the movie, I had my wife's pistol all back together and her new Huening plunger fitted nicely with a buttery smooth trigger pull set to 2 lbs and 3 oz.

If you have any questions, feel free to ask; if you have any other experiences working with this plunger, do share, I'd like to hear about how you fitted your plunger.

My next fittings are the Henning Hammer and Sear Pins!

Edited August 20, 2010 by eastonx7

[J-Ho]

I think your method is absolutely terrible!

How can you watch Hot Tub Time Machine? Other than that I did pretty much the same. Although I don't think my was quite as bad.

[Skydiver]

How did you keep the Dremel quiet enough so as not to disturb the amazingly smart dialogue of that movie?

Actually, thanks for posting all that information. It'll be useful when it'm my turn to attempt the same kind of install.

[shooterbenedetto]

That's exaclty what I did last year!

glad you have done this to the gun. You will love

it once installed. Next task is how do you maintain

the trigger SET and not move..matches after matches..

my trigger settings moved every after local matches until

I found how to set maintain it.

I'm sure you will find that if you know how to do this.

Edited August 20, 2010 by shooterbenedetto

[sinnsyk]

Edwin

I modify my Huening rollers the same way. It is necessary to round it to make sure the roller is working correctly. I've done one for George and sent it to him and I know he's working on generation two of them. I also use a lighter spring that I make. I'm hoping to have a selection of lighter springs available soon. The guy doing them for me isn't super quick, but he makes good springs. So I'll have a 0.018", 0.019" and 0.020" wire diameter trigger plunger spring for tuning purposes.

[eastonx7]

I think your method is absolutely terrible!

How can you watch Hot Tub Time Machine? Other than that I did pretty much the same. Although I don't think my was quite as bad.

LOL, it was HTTM or Karate Kid (Kung-fu Kid), I opt for HTTM because who doesn't love 80's hair?

I definitely learned a lot about the trigger bar plunger and trigger bar engagement by just fitting those two pieces. I'm glad that you didn't have as much to do with your plunger - I must have taken the system apart about 10 times to get ti just right!

[eastonx7]

How did you keep the Dremel quiet enough so as not to disturb the amazingly smart dialogue of that movie?

Actually, thanks for posting all that information. It'll be useful when it'm my turn to attempt the same kind of install.

I'm happy to hear this! If it helps just a little, I feel good about contributing to this forum. Tanfos are a little difficult to find information on and Henning's done a great job building a community to support a great platform.

[eastonx7]

That's exaclty what I did last year!

glad you have done this to the gun. You will love

it once installed. Next task is how do you maintain

the trigger SET and not move..matches after matches..

my trigger settings moved every after local matches until

I found how to set maintain it.

I'm sure you will find that if you know how to do this.

You know it! My wife loves the way the trigger feels and she really likes the reset - it's quick and short.

I'm not quite sure if I understand what you are describing; based on my wife's gun, taking it apart and putting it back together seems to be consistent. If you're describing the trigger reset and over travel screws, they seem to be consistent too; however, I did blue LocTite them in well.

But, I'd be interested in the tweaking you had to do to keep things consistent for your pistol.

[eastonx7]

Edwin

I modify my Huening rollers the same way. It is necessary to round it to make sure the roller is working correctly. I've done one for George and sent it to him and I know he's working on generation two of them. I also use a lighter spring that I make. I'm hoping to have a selection of lighter springs available soon. The guy doing them for me isn't super quick, but he makes good springs. So I'll have a 0.018", 0.019" and 0.020" wire diameter trigger plunger spring for tuning purposes.

Hi Henning!

I'm looking forward to the new plunger; let alone the new springs. I've been toying around with the factory spring and I've cut 2 coils already. Basically just enough spring tension to reset the trigger bar after disconnect. I was surprised to discover how much this spring affects the trigger pull.

[coolsf]

Good morning Everyone!

Yesterday, while watching Hot Tub Time Machine, I decided to fit the Huening Rolling Trigger Bar Plunger to my wife's Eric Open. The process was a little more involved than anticipated, so I thought it would be a good idea to share my experience.

The first step I made was to drop the parts in to see and feel how everything fit. I noticed three things:

1) The Huening plunger spring was much lighter than the factory plunger spring; this was good because it confirmed the notion (mentioned in another post) that it was alright to lop off 1.5 - 2 coils from it. I opt to lop off 1.5 coils from the factory spring and use it with the Huening plunger. I wanted to keep the Huening spring as a backup.

2) The roller wasn't rolling! The Huening plunger housing was making contact with the trigger bar (that beautifully polished pocket that meets the factory trigger bar plunger - yes, yes, we all know it soooo very well); I shouldn't say making contact though, I should actually say scraping and grinding. This is where all the fitting occurred - for about 30 minutes.

I started the process by taking a small file and rounding out the edges that were making contact. Which edges, right? Well, because the underside of the trigger bar is beautifully polished to a mirror finish, I took red permanent felt marker and coloured all shiny surfaces. I dropped the parts back in and pulled the trigger a few times. The areas that didn't have red markings were friction points, and made it very easy to figure out which edges to round out.

After 10 minutes, I gave up and pulled out the big file - more affectionately known as the Dremel! Before I did this though, I punched out the roller's pin so I wouldn't damage it. It also gave me a better angle of engagement to work with. Because I was dealing with 4,500-5,000 rpm, the housing was a little too small to hand-hold - I like my fingertips the way they are; I ended up using a punch that fit nicely through the neck of the housing and held it in position with my thumb - giving me all the surface area necessary to do the work.

If you take a look a the picture below, you'll see the original (left) and the modified (right). Based on the way the housing fit to my wife's pistol and trigger bar, I needed to perform two modifications:

1) to round out the top edges - similar to the factory plunger's profile

2) taper the nose, to eliminate the contact that the housing made with the trigger bar - past the polished pocket

You'll notice that more of the roller has now been exposed and there's enough meat to the housing that will still keep the roller's pin in place.

Note: the profile I came up with may very well be different in your pistol, so do be careful with your modifications.

Once I finished shaping and polishing, there was only one modification left.

3) to polish the dowel that the spring and the roller's housing plunged upon. I simply took 600 grit sand paper and lightly polished the surface. I spun the dowel in a drill to be sure the shape did not change.

Well, by the end of the movie, I had my wife's pistol all back together and her new Huening plunger fitted nicely with a buttery smooth trigger pull set to 2 lbs and 3 oz.

If you have any questions, feel free to ask; if you have any other experiences working with this plunger, do share, I'd like to hear about how you fitted your plunger.

My next fittings are the Henning Hammer and Sear Pins!

[coolsf]

I bought the Henning rolling plunger. I encountered problem during my installation.

Q1. This plunger can't be compress like the original one. I can't figure out what is the purpose of the spring. There is no locking mechanism on the shaft and the rolling housing. Please refer to the picture. The shaft is very tight to fit into the rolling housing.

Q2. Notwithstanding the above issue, I installed the plunger into the frame but I couldn't align the trigger so that the trigger pin could go through. Is the housing too big? Am I supposed to file the edges?

Q3. Did I put together the plunger correctly based on the picture?

Could you please shed some lights? Thanks

[shooterbenedetto]

roller should be installed facing the front of the gun.

it should also be relieved by filing the sides of it

to make sure it makes contact with the trigger bar.

[coolsf]

i installed it with the rolling facing forward. I guess it is the housing that obstructs the correct alignment of the trigger. I will try to file the edges. With the spring, a normal plunger can be compressed. However, this is not the case with this one. Is the housing supposed to move up and down freely from the pin? Thanks

[shooterbenedetto]

Yes, housing can go up and down.I think so? as long as you got the plunger installed so that the mag release is functioning.

[Mo Hepworth]

is there a retention pin that could have walked loose on the shaft? (ie: same very small pin you push to remove the spring)

[Skydiver]

A quick note for people installing the rolling trigger bar plunger: The pin that retains the mag release maybe bigger than the stock trigger bar plunger. (For me it was 0.010" bigger.) The effect this has is that the mag release doesn't go down as deep anymore so some magazines may not eject as freely as before.

There are two approaches to fixing this problem:

1) Make the channel in the mag release that takes the plunger pin a little bit wider. Trim towards the button side.

2) Trim down the ledge in the mag release that holds the magazine.

Approach 2 is much easier because it's easy to use a pen or pencil to mark the excess that is sticking out and simply trim it away. The downside of this approach is that now you have less material holding your magazine in place.

Approach 1 is much more work because of the constant fitting and re-fitting to make sure enough material is removed, but not too much otherwise installing the plunger back in will become extra challenging. :-)

(Now as I'm typing this instead of actually doing this at 3 in the morning, I now realize how I could have made approach 1 much easier. I should have used a pen to mark the excess as in approach 2. Instead of trimming that off the ledge, I could have measured the width of the mark on the ledge and used that to determine how much to remove in the channel. Duh! Hindsight is 20/20 and not sleep deprived.)

[DarthMuffin]

A quick note for people installing the rolling trigger bar plunger: The pin that retains the mag release maybe bigger than the stock trigger bar plunger. (For me it was 0.010" bigger.) The effect this has is that the mag release doesn't go down as deep anymore so some magazines may not eject as freely as before.

There are two approaches to fixing this problem:

1) Make the channel in the mag release that takes the plunger pin a little bit wider. Trim towards the button side.

2) Trim down the ledge in the mag release that holds the magazine.

Approach 2 is much easier because it's easy to use a pen or pencil to mark the excess that is sticking out and simply trim it away. The downside of this approach is that now you have less material holding your magazine in place.

Approach 1 is much more work because of the constant fitting and re-fitting to make sure enough material is removed, but not too much otherwise installing the plunger back in will become extra challenging. :-)

(Now as I'm typing this instead of actually doing this at 3 in the morning, I now realize how I could have made approach 1 much easier. I should have used a pen to mark the excess as in approach 2. Instead of trimming that off the ledge, I could have measured the width of the mark on the ledge and used that to determine how much to remove in the channel. Duh! Hindsight is 20/20 and not sleep deprived.)

I'm installing my roller plunger now, I see the problem you're referring to.

I went for option 3, which was to chuck the shaft of the new plunger in my dremel and sand down the mag release end until it was the same size as the old one.

Seems to work nicely -- haven't test fired yet.

Edited January 9, 2011 by DarthMuffin

[AJW]

A quick note for people installing the rolling trigger bar plunger: The pin that retains the mag release maybe bigger than the stock trigger bar plunger. (For me it was 0.010" bigger.) The effect this has is that the mag release doesn't go down as deep anymore so some magazines may not eject as freely as before.

There are two approaches to fixing this problem:

1) Make the channel in the mag release that takes the plunger pin a little bit wider. Trim towards the button side.

2) Trim down the ledge in the mag release that holds the magazine.

Approach 2 is much easier because it's easy to use a pen or pencil to mark the excess that is sticking out and simply trim it away. The downside of this approach is that now you have less material holding your magazine in place.

Approach 1 is much more work because of the constant fitting and re-fitting to make sure enough material is removed, but not too much otherwise installing the plunger back in will become extra challenging. :-)

(Now as I'm typing this instead of actually doing this at 3 in the morning, I now realize how I could have made approach 1 much easier. I should have used a pen to mark the excess as in approach 2. Instead of trimming that off the ledge, I could have measured the width of the mark on the ledge and used that to determine how much to remove in the channel. Duh! Hindsight is 20/20 and not sleep deprived.)

I'm installing my roller plunger now, I see the problem you're referring to.

I went for option 3, which was to chuck the shaft of the new plunger in my dremel and sand down the mag release end until it was the same size as the old one.

Seems to work nicely -- haven't test fired yet.

I installed mine today, I had to use the factory plunger shaft as the lower part that is retained by the mag release plunger was 0.5mm in diameter thicker and mag release travel tightened right up but apart from that now with that, 13 pound hammer spring, flat trigger kit and over sized firing pin I'm sitting on 2 and a bit pounds trigger pressure...will test it on the range tomorrow.

[Mo Hepworth]

How did that work out for you?

[Mo Hepworth]

I installed mine in my limited custom and now seen the effectiveness of it on the trigger..especially the pre travel...which I prefer a little of...

There is no creep at all,..or movement of the steel sliding on steel. The roller is working well.

[spideysteve]

This thread is about a year old, but good info about the plunger. I'm going to be doing my install tonight and this thread was a big help.

Thanks for the info

[Mo Hepworth]

I now have my plunger installed in the OPen gun I put together...works awesome. I replaced the trigger return spring as the old one was bent and weaker (I prefer a fast reset)

[spideysteve]

Mo .. Did you shave it down like the pics above or put it in as it came?

[CHA-LEE]

I prefer to use the stock plunger. You can polish up the stock plunder and trigger bar well enough to allow it to perform just as well as the Huening Roller version. Get both mating surfaces smoothed out and polished up and then put a dab of slide glide between them and its smooth as glass for many thousands of rounds between cleans.

[Mo Hepworth]

Mo .. Did you shave it down like the pics above or put it in as it came?

I shaved it down...be VERY carefull you do not shave it down to the point you cut thru to the wheel axle holes. ONly take off what you need to press and reset with only the wheel making contact. Reset is smoother as well.

IMHO,...I think using the plunger would make it more reliable as well. After enough rounds, that area gets dirty/grimey as well as the sides of the trigger bar..etc. THe wheel will not get clogged up, and there is less resistance for reset, and let off with the wheel is smoother. If you have ever experienced it, my trigger was having a harder time resetting. (just slower due to being dirty + weakened TRS). It happened on my LImited a few times, as well as Open gun...think of it this way; steel rolling over steel, or steel sliding over steel. The wheel is smoother.

Edited January 9, 2012 by Mo Hepworth