Marauder Project – Installing A Regulator   35 comments

Greetings All,

Yesterday I had some time to install the regulator I purchased from Vincent van Gerven at Airgun Exporter. So I decided I would document what I did to install it and my steps in tweaking.

When I received the regulator, it was set already preset to 130 bar and loctited so the adjustment would not move (I could have moved the adjustment, but I choose not to). I have not changed the setting from 130 bar as I was hoping the FPS would be in the ball park of 920fps. There was not really any documentation that came with the regulator regarding how to install it. I received a personal typed note stating previous results others have been able to do, a few things to be careful of, and what Vincent has done and his results.  I emailed Vincent requesting a larger image and some tips for installation. Vincent replied with the a link to JohnB’s post stating that  should get me started and attached a larger image. Vincent has responded each and every time I emailed him. I received the regulator quickly and promptly after paying via Paypal.

Here is the pictures Vincent sent to me. Perhaps someone else can use them as a future reference. 🙂

A question posed to me is do I  “think that the documentation that came with the regulator was adequate?” It depends on your perspective. If the question is about installation instructions, then no. I receive no specific installation instructions. In fact, if I did not know JohnB then I may not have wanted to purchase the regulator in fear I may destroy something. However, this is the reason for this blog posting. I tried to provide enough detail so another individual can install the regulator with some ease (there will always be variances in how one installs). If your perspective is overall documentation regarding the regulator, then yes. The above picture was provided and clearly explains how to change the pressure. Also, Vincent had the following statements in his email to me.

If you find it regulates well but thereʼs not that many shots, then try backing off the hammer spring and shorten the hammer travel.  (youʼre then wasting air by a valve that stays open too long during the firing cycle.) you might also use a too high of an output pressure.

Be careful when you adjust the power on the dial, Itʼs a delicate piece of kit. Turn it counterclockwise first since a thread-sealer is used.

Please do ask if you have any questions.

Happy shooting,

Vincent van Gerven

I do not require a step by step instructions on how to install the regulator. I believe we are intelligent created human beings and able to ascertain some sort of answer. In my case I have no previous experience with air rifles ( or rifles in general.. at all), so I read some posts and talked with John about how he installed his. I did need some guidance to get me started on the installation.  So the answer is really determined by your perspective. I will let you decide. 🙂

Before the regulator I was filling the gun to 2000psi and getting about 20 shots at 920 fps with a 20fps extreme spread. The ending pressure in the rifle was about 1600-1700psi.

To begin, one must first depressurized the gun. The Marauder rifles makes this process very easy.

The depressurization only took a few seconds.

Next was the task of removing the front valve(?) so one is able to insert the new regulator.

I used the barrel band to loosen valve and then used a wrench to un-thread the valve the rest of the way. When pulling out the valve,  be sure to gently pull straight out. Do not try to screw out the valve after the threads. (NOTE I would not advise using a wrench. I found the valve is actually two parts and you could unscrew them. Others have noted this also could do some damage. One suggestion made to me was to use a rubber wrench similar to the ones used on oil filters.)

Do not try to screw out the valve after the threads. The threads inside the tube will slice up the O-ring on the end of the valve (see Figure 3).

Gently set the valve aside and begin to remove the air pressure gauge. I am removing the gauge temporarily for testing. Once I find the regulator is working properly, then I will install the gauge and drill a hole in the tube for the regulator vent.

I found a small O-ring in the bottom. Be sure to put the air gauge and the small O-ring in a separate bag as well.

Now the prep work for the regulator begins. I determined early on that I would be inputting the regulator for testing first and then later install permanently.  Thus I would need to ascertain a solution to be able to remove the regulator. In a previous post on the Airgun Advice forum, John shows to use steel suture. I called John and found he had issues with the steel string. He later used a thicker gauge wire. Well, around this farm there is an abundance of electric fence wire. So this is exactly what I used (See Figure 5). It is very stiff and thick enough to be able to pull it out later.

As you can see, I simply wrapped the wire around the regulator and tried to flatten the wire back to the regulator.

Next, the air pressure gauge holder needs to be removed. I put a larger allen wrench in the opening and pushed the gauge holder to the front of the tube just a bit. This will give you clearance for the one-of-a-kind tool needed for this job.

A coat hanger is used to pull out the gauge holder (See Figure 7). Note: when it comes to the internal threads, be careful and again – just gently pull straight out. Do not try to tread out the part or you will need to purchase new O-rings.

Here is a photo showing the difference in the length of the gauge holder (left) and regulator (right).

Since there is a size difference, this will need to be compensated for. One can see from the picture above there is a difference in height and the vent hole on the regulator may not line up in the center.  Also, there needs to be some “breathing” room behind the regulator.  Since I did not need much room,  again needed to determine what might work.

Since farmers generally keep just about every scrap piece of whatever, I knew there would be something I could use in one of the barns. I found a 1/2″ piece of PVC pipe. I silvered off, with a hack saw, about 1/4″ piece to raise the regulator. However, there was not much space  for the air to move through and I knew in a 3/4″ hole…  how would I center this piece?  I found a 3/4″ piece of PVC pipe , silvered off another 1/4″ piece.  Not only is it the perfect diameter across, it gives enough room (I felt) for the air to flow through. And more importantly I can now very easily center the spacer.

Here is a photo showing the new PVC “spacer” beside the gauge holder.

I took the 3/4″ space and gently worked it past the threads. Then, I took the 1/2″ PVC pipe and push the new spacer into its new home. the PVC pipe made it very easy to push the spacer evenly all the way back to the rear of the tube. The picture below is not very clear, but you have the idea.

Now, at this point (admittedly a bit late) I am curious about removing the spacer. Well, I decided to test using the handy-dandy coat hanger and complete the same process as before. I was able to remove the spacer with a bit of patience and keeping the spacer straight (it would get a bit sideways and I would need to straighten it out).  With this portion confirmed, I know I will be able to install the regulator later in a more permanent position.

With the spacer installed, I gently installed the regulator. I had my action in a gun vice upside-down so I would be able to align the vent hole on the regulator with the gauge hole. I drew a line with marker from the vent down so I could tell if I was off and by how much. I used the 1/2″ PVC pipe again to push the regulator back slowly. I found that I could twist the PVC pipe just a bit if needed. This would in turn twist the regulator. It took a few tries but I got the regulator vent hold inside the gauge hole. However, the hole was not in the center.

To center the vent hole, I took a very small allen wrench, inserted into the vent hole, and GENTLY moved it around to the center.

Since there was an excess of wire hanging out, I cut the wire flush with the end of the tube. I then took needle-nose pliers and bent it into a half loop. This way I should be able to grab the wire and remove the regulator later.

At this point, I reinstalled the valve and again using the barrel band as a type of wrench to tighten down the valve.

With everything installed, I pressurized the gun and sat back grinning at my work.

Well, it may have a pleasing appearance but the function is what counts in my book. I had the rife tuned to have an average of 920fps over 20 shots with a 20fps extreme spread.

Well… instead of typing everything and hoping everyone just believes me. I now filled the gun to ~3000psi and the results are just wonderful. Here are the pictures from the crony.

Highest FPS

Lowest FPS

Average FPS

Extreme FPS Spread

Standard Deviation

Number of shots

(the “2” represents the second shot string)

There is no need to adjust your glasses or your monitor. Those numbers are correct.

I noticed if I drop the last four shots the numbers are as follows.

High – 883
Low – 868
Average – 875
Ex. Sp. – 15
Standard Dev. – 3

A last few items that I must mention. The first shot string started out with numbers at around 840fps.  I messed with the hammer spring and stroke to get everything working properly. Once that seemed to be working, I opened the metering screw about 1&1/2 turns (3 1/2 total).  This is how I received the above numbers. I noticed that at about 3 to 3 1/2 was enough. After that, the turns did not matter as the FPS did not increase.

Lastly, if you put your hand over the hole, it will drop the FPS. I believe this is the reason for the lower number FPS in the middle of the sting.

Well all, that is about it for now. If you have any questions, feel free to email me or post them below.

Until next time,
“Enjoy our wild America”  – Marty Stouffer

In Him,


Posted July 10, 2010 by avv604 in Airguns, Marauder

Tagged with , , ,

35 responses to “Marauder Project – Installing A Regulator

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  1. Hi Jeff, you should never use your fill nipple to remove the fitting from the end of the tube. Your chrony shows EX spread as 18, but you have 15 listed in your article.
    Last I remember you were having accuracy issues with your M-rod, what became of that?

    Can you do this?

    • Greetings Rickster,

      Thank you for your tip.
      For the chrony, if you read my last statement I believe that will answer your question. 🙂

      You are correct, I was having accuracy issues. It was due to using the wrong pellet. The .177 really likes CPHs. I thought it likes the Barracuda’s… but I guess not. 🙂

      Regarding the picture, there is not really enough information there to answer your question. I am not sure how many shots that is or how large of a hole that is. Nice grouping though.


      • Thanks
        5 shots, at each red dot.
        The red dots are almost 3/4 inch.
        The 2 groups are about 1/4″ C to C

        I haven’t tried the Barracuda’s @40 yds, but they seem to group pretty good at 20.
        I finally got some JSB Exacts Heavy and tried them @20 yds.
        They don’t shoot as tight as the CPHD do in my M-rod.
        I got similar resluts with the JSB Exact 8.4gr.

        My M-rod is actually getting a rest, while I break-in my RWS 52. Which prefers the JSB Heavy’s, and the Beeman Crow-Magnums so far @18 fpe for both.


  2. Jeff,
    Thank you for the write up and clear pictures. This should be very helpful to many people.
    I used the barrel band to just loosen the “end cap” or “fill valve/plug” then used a rubber strap wrench to unscrew it the rest of the way. I also used a piece of foam (make sure it is of a type that will noy break down fast) and laid that inside the stock inletting to offer some protection against dust entering the vent hole.
    Great numbers, great job getting it dune.


    • Greetings John!

      Putting a piece of foam in the tube is a great tip. I did not think of that. Also, thank you for the other tips and howtos regarding the regulator. Sorry I missed you at the match today.


  3. Great numbers! Were can i purchase the regulator and at what price? Do they take paypal?

    morris williams
    • Greetings Morris,

      If you search the Yellow forum for regulator you will find Vincent. Also, you can click on the link above and I believe his email address is on his web page.

      I paid $100 via paypal for the regulator. 🙂


  4. Another great post, Jeff. I must say that I really enjoy following your Mrod journey. Question(s)…. what was your beginning and ending supply pressures and what pressure was the regulator set to when you received it? Also, did you think that the documentation that came with the regulator was adequate? Again, thank you for the effort and clarity of your posts.
    Praying God’s blessing upon you and your family that His light might continue to shine through your lives.

    • Greetings John,

      What great questions. I forgot to add that information. My apologies. I will update the post with the information.


    • John,

      I updated the post answering your questions. Also, I tried to answer another question posed to me. Hopefully this helps. 🙂

      Have a blessed day!

  5. Great blog Jeff !!! i know i should have put up something similar to what you wrote here on my site, but i’m just too darn busy at the moment 🙂

    happy shooting, Vincent/Airgunexporter

    • Greetings Vincent,

      I know you are super busy. John told me about all the different items you import/export. If you like, you can use this site as a reference for a Marauder installation. If something needs to be tweaked or changed, just let me know.

      By the way, I am just tickled silly with the regulator. I shot a whole 60 shot FT match the other day and never filled up. It was just wonderful to never have to worry about filling up between lanes. Plus I believe my score improved (42/60). Hopefully later I will post about installing with the gauge installed.

      Thanks again Vincent,


  6. All,
    I found the original posting for the first drawing above.

    The gentleman has his regulator in a .22 Marauder.


  7. Hello, you can shown a photograph of the lower part of the marauder? How made you to give the gauge? Thank you

    Bom-dia, podem mostrado uma fotografia do abaixo do marauder? Como feito vocês para entregar o calibrador? Obrigado

    • Greetings Marc,

      I am not sure what you mean my lower part. Are you referring to the internal or external lower portion? Also, by lower portion I presume you mean the lower part of the action?

      Let me know, I am happy to try an help.


  8. Greetings John,

    You can poster the photographs about installing with the gauge installed?
    Thank you

    • Marc,

      I have not installed the regulator with the gauge yet. Since the warranty is not out yet, I do not want to drill into the air tube if I do not have to right now.


  9. Hi just wondering if you did the other mods or alterations to the gun, Listed in the picture diagrahm in red? THanks JIm

    • Greetings Jiminee,

      Besides the stock, no. I have added a Hawe Sidewinder 30 atop the .177 and getting ready for HFT this year.

      I did just polish the inlet of the barrel and pulled a few patches of JB paste through the barrel. That seemed to help a bit. I am going to use my Dremel to polish the inlet next time. Hoping that will help with the fliers. 🙂


  10. Hey Jeff, Great write up. Curious though, does the regulator replace the gauge block or sit in front of it. From the diagram posted above, the regulator is shown in front of the gauge block but in your discussion you didn’t reinsert it? Thanks. Steve aka Supercharged86 @

    • Greetings Steve,

      The drawings above came with the regulator. The drawing is something someone else did. I did not follow what the drawing shows.

      I installed the regulator without the pressure gauge. Why? Well, I did not want to void the warranty just yet. 🙂 Also, once you drill a hole in the tube you can not go back. However, it is not a big deal at all. After shooting with it a few times, I quickly learned when the rifle was out of air.

      Thank you for your comment. 🙂


  11. So if I got it right you are getting 64 shots at a 875 ave. with a 300 psi fill. I am thinking about doing a regulated .177 in mrod for fun in the back yard. what type of groups will it hold ? I would loke to be able to plink with out all the fill ups and want to drive tacks as well. Maybe some day get out to a shoot of some sort not sure what we have around Wisconisn but I got a big back yard and need a quite shooter ;D

    • Greetings Jiminie,

      Yes sir, you are correct! I have filled it to 3200psi and got 70 consistent shots. It would be nice if a reg could be put in a .22 in the “drop-in” manner. I may have to see one day what I can get with the .22. 🙂

  12. Ya I got a .25 mrod I would love to see a drop in reg. for. Right now I get 24 shots from 3000-2000 ending psi and can hit a large soup can at 70yrds everytime standing no bench 🙂 I guess for hunting it will work but say 40 shots would be nicer 🙂 I am thinking I am gonna do a regulated .177 I like the gun and if I can get 70 shots I will be happy! Plinking heaven I can turn up the velocity on the .25 and get 23 good shots but my ending pressure is at about 1600 then I loose the can at about 22 shots and then have to go to the next mildot for 23 and 24 then I just call it quits. I can just about shoot thru a 2×4 at 10yrds though with the metering screw out 4.5 turns :O drops bunnies on the spot!!! Well thanks for the great post!!!

  13. What were your setting for:
    Hammer Spring tension:
    Hammer Stroke:
    I see the velocity is 3.5 turns but wanted to see those other two?

    Also do you still have the settings when you were running without reg?


    • Greetings Johnny1,

      The settings with the regulator – I am not sure. I pretty much left them they way they were before. I only really adjusted the velocity (metering screw) to get the max FPS. For the previous settings – see my other blog postings on tuning the Marauder.

  14. Pingback: estos links de regulador del marauder

  15. Hello Jeff
    I havwe been reading your posts on the Marauder regulator and am really impressed with what I see. I would love to add a regulator to my mrod but I am still not quite sure as I have some concerns. My first concern is the difficulty of thw install. How hard is it to do right? What do I need other then the regulator for parts. You mentioned some pvc pieces that I was unsure of how they fit into the picture.
    Also the gage do you leave that out or can you put it back in? I have heard people say it goes in and aome say it stays out.
    Finally, I have a 22 caliber. I have seen no reviews or data on the 22. What can I expect forshot count and velosity?
    I know thats a lot of questions, but your imput would be greatly appeeciated. Thanks in advance and may God bless you and yours.

  16. Just installed the Regulator in my .22 Marauder …. Fantastic results !!

    MARAUDER … Regulator results using Bstaly tune also …

    Postby Motorhead » Mon Aug 06, 2012 10:47 am
    Installed the Regulator from “Air Gun Exporter” this morning KEEPING the factory gauge intact.
    Modifications to rifle have been on going, so in all fairness list of mods done are listed below …
    Ported valve body, size reduced valve stem behind seat, Valve sleeve removed, .165″ transfer tube, Gauge block milled out large as possible.
    Bstaly type tune using an @ .375″ wide x 1/4″ wall silicone tubing piece as hammer bumper. *Air tube drilled for Reg venting.

    First couple clips were to get preliminary hammer travel & spring preload set so velocity was very close to my #850 fps target speed gun was at prior to regulator.
    Hammer ended at 4 turns preload from full CCW. Hammer travel not counted due to Bstaly bumper being in place. Valves adjustment screw / port set wide open.

    ** Only had 2700# in the Scuba tank so fill pressure started there ** Regulator set at 130 bar or @ 1850#

    Shot with .22 cal JSB 18.1 pellets over a Shooting chrony Beta …

    * 2700# fill NOTE: Rounded to nearest fps no decimal point.
    ~~ Fell off Reg from here
    Quit the string ….

    So with a 2700# fill and a reg at @1850# in this test Gun used 850# of air for 20 GREAT shots.
    This works out to @ 42.5# per shot.
    High Velocity 860 fps
    Low velocity 850 fps
    Extreme spread 10 fps
    Standard Deviation average don’t know how to figure that ??? … but dang little !!

    Needless to state .. I’M STOKED !! this is simply awesome shot consistency.

    This tune is at a HIGH POWER setting being @ 30 Ft Lb energy level 😮
    Know shot count is not that great … Just guns first tune seeing how well a regulator could do at a MAX power setting on a heavily modified gun … Not to shabby actually.


  17. Great Information. Just curious as to the install instructions for using the regulator with the pressure gauge installed. Is There a spacer needed between the gauge holder and the regulator If so what size? Where to drill vent hole for the regulator? Does the regulator move at all inside the air tube front to back or even spin. What keeps it in place? Just looking for more detail thanks.

    • Greetings Adam,

      Above I address the need for a spacer. There has been some to install without a spacer; however, that is against the manufacture’s instructions. If you are to install the regulator while the gauge is still installed, then one will need to input the reg before the gauge (which would be toward the fill end). So one would still follow the instructions but you will need to drill a vent hole in the stock. That is about the only difference between the two instances.

      What keeps the regulator in place? Review the pictures above and note the O-rings on the regulator.

      Does that help?


  18. Very interesting and informative article you have on the regulator! Thanks a lot for posting these instructions.4
    I went on Vincents website and I could not find the regulator available. I read on one of the forums that he no longer sells them.
    Where can I buy one of these for my .22 Marauder?

  19. Link exchange is nothing else but it is only placing the other
    person’s blog link on your page at proper place and other person will also do similar in favor of you.

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