Marauder valve lift limiter. A different approach.

[PikeP]

Does it work? Yes.
Is it adjustable? Yes, externally.
Is it an easy DIY item. Yes.
Can I adapt this to other gun models? Yes, more than likely. and plenty of ways to skin the cat.

The How:



You can see I basically have 2 strikers, the recessed compressed leather striker (with over 2000 shots on it  ) that makes initial contact with the valve stem, and the adjustable 8-32 mm screw with o-ring adhered to the face, that will make contact with the valve body, limiting the lift depending on how far out or in its adjusted.



I drilled and tapped the hammer to accept a 8-32 screw, which is adjustable via the rear adjuster with a normal hex/allen key. The 8-32 had a small o-ring adhered to the face (not pictured) to allow buffer of the limiter. This buffer is very important, and I intend on one day using a .125" Buna sphere/ball in the o-rings place...but so far the o-ring I use works at intended. As you see it was a tight fit for the 8-32 screw.

The Why:



.56% es over 24 shots at 60 fpe? Yes please...and the wonderful thing is, I can take my tunes down the slope by 30-40%, and when set up with the valve limiter still see these amazing extreme spread values.

To stage/setup...I like to back the limiter out, set my tune 10-30 fps over intended value, and then use the limiter to back the fps down again to intended. Its another step in tuning, and I honestly will only use it from time to time, but right now its set for the 60 fpe tune and I am pleased as punch with the results and will leave that be.

Happy tuning and tinkering!

[PikeP]

I should add, the pellets shot weighed between 34gr, and 34.6gr, average 34.3 gr. The variation in the .56% / 5 fps spread, was essentially variation left in the weighed pellets. Being at this tune and pellet weight I see roughly 1 fps variation per .1 gr of pellet weight variance...

Not bad, not bad at all.

[UnderPressure]

Nice!

Do you have any examples of this working off the reg too?

Maybe an efficiency tune with a high reg set point?

P.S. Was thinking how interesting this would be if also using  a Lane regulator ---> https://www.gatewaytoairguns.org/GTA/index.php?topic=174561.0

[PikeP]

Nice!

Do you have any examples of this working off the reg too?

Maybe a tune with a high reg set point?

P.S. Was thinking how interesting this would be if also using  a Lane regulator (for a pseudo plenum effect when off the reg--->

I don't really tune to shoot off regulator by much on this particular arrangement. I would assume the valve lift limiter just limits the ability to create a bell curve depending on how much buffer you build in, with how much buffer I built in, I'd imagine I can go around 200-300 psi under regulation without any ill effects.

[triggertreat]

Interesting idea!  Leather faced striker and with O-ring adhered I know won't last, especially at 60 FPE.  Do you have a striker picture?  I don't see a recessed striker, so how is this suppose to allow the second striker to make contact when it looks like the striker face would be covering the second, added striker?  Just trying to understand this more.  I also would be worried about the second striker being of metal digging a hole in my particular aluminum valve body, plus the added noise.  Thanks.

[PikeP]

Interesting idea!  Leather faced striker and with O-ring adhered I know won't last, especially at 60 FPE.  Do you have a striker picture?  I don't see a recessed striker, so how is this suppose to allow the second striker to make contact when it looks like the striker face would be covering the second, added striker?  Just trying to understand this more.  I also would be worried about the second striker being of metal digging a hole in my particular aluminum valve body, plus the added noise.  Thanks.

You're so negative, sure just gloss over 24 shots at 60 fpe with 5 fps / .56% es...

The leather striker has well over 2,000 shots (probably 3,000+ by now) at this power level on it, with zero change. Its been in the gun for 2+ years like this. Its clearly recessed, and that recess amount has been measured at .03" (has been re-measured at least 5 times over its life). The primary reason for the recess in the striker is so that there is a pocket/well that retains the leather... I will never, ever be going back to anything else, in fact say it were to fail at the 3+ year mark...the leather I used was not even genuine quality leather...so that should speak volumes for the likes of kangaroo leather...so I'd simply upgrade the material, and be good for probably 5+ years...but my guess, is the current leather that is packed very, very well...will last the life of the rifle, certainly will outlast me.

The second striker (lift limiter that strikes valve body) has an o-ring attached to the face (not pictured), by the time the o-ring faced 8-32 mm screw hits the valve body, there is barely any hammer energy left sending it into the valve body...so even if there were no o-ring there, the valves body would not be taking any considerable damage.

This current setup has over 500 shots on it, has been dis-assembled, and inspected to see zero change...

Here is a picture of the oring




Let me draw on this picture, where that o-ring went...



And another close up of the leather striker, you can see where the valve stem makes contact and has further depressed (permanently deformed) the leather..





You're so concerned with how the cat was skinned, that you're forgetting that the cat was successfully skinned, and that you can go about it however you please, but all being said...I am very pleased with my execution. The leather striker long predates my lift limiter and has nothing to do with this modification, so any criticism towards it is outside the realm of what this thread is even about, and your further critique stems from misunderstandings.

[PikeP]

Another great benefit of valve lift limiters and buffers, is that you gain the ability to remove the majority or all of variation you get from reg creep and other potential regulator fluctuations, balance valve stiction, shot angle variation resulting in slight change in hammer strike, other hammer strike anomalies, and you can learn overall how much lift you need for different power levels to pique one owns interests if you please. I did exactly that to verify my calculations on my spreadsheet and made minor tweaks to bring them in even closer (I was surprisingly close).


Fx Impacts, Jsar Raptors, and I believe even the Cothran valve, all sport different methods entirely from each other, and myself to obtain identical results by limiting the poppets lift from its seat (provided the user knows how to tune them correctly) For the 30 cents that went into this mod, it is by far, hands down, the most beneficial one I have personally done, and if you know me, I've done just about them all.

Another look at the string data (my spreadsheet app that is in the works automatically copies this data to clipboard upon request. Pretty neat)

Marauder
Date:   Temp:  60
Chronograph distance: 1ft
Loss from Chrono Distance: <1 fps
Chrono Loss Added: No

Projectile Mass: 34.3 gr  -   Ratio to Air: 71.3% / 28.7%
Psi Start: 3250   -   Psi End: 1900   -   Air use: 1350 psi
Psi / Shot: 56.3/201.7 -   CC / Shot: 6.03   -   FPE / Psi: 0.3
Res Vol: 190cc   -   Reg Vol: 53cc   -   Set point: 1975psi
Shots On Reg: 22   -   Shots Off Reg: 2   -   Total Shots: 24

                          Efficiency: 1.31 FPE/CI
                                Valve Close @: 36%

                     ES: 5 fps ( 0.56%)    -    Std Dev: 2

            Total FPE: 1442       -       FPE Per in/Barrel: 3.1

 Total Shots < 1% ES: [24/24] best streak: [24] shots [#1-24]

             Fps/FPE High      Fps/FPE Avg      Fps/FPE Low
                  891 - 60             888 - 60              886 - 60

(1-10)   890 - 889 - 887 - 888 - 890 - 891 - 890 - 890 - 889 - 887
(11-20) 886 - 886 - 891 - 886 - 887 - 886 - 889 - 891 - 890 - 886
(21-24) 887 - 890 - 886 - 886
                     Most repeated: [886] Duplicates: [7]

[triggertreat]

"Interesting idea!"   I thought that would be taken differently, and you know I am very detailed like you.  I didn't mean to offend with simply asking more about your idea and giving my experiences.  I probably should have handled my reply with a little more sensitivity.  I am not a powder puff type of guy (not saying you are either to be clear) and can slip easily with the sensitivity stuff.

I have worked with a pocket of leather and O-rings in the past myself.  I even slipped some super glue into the leather to stiffen it more, which made it last a little longer by the way in my application.  The things I also took mental note of was the mushrooming second striker and how that would change the tune as well in time, especially with an O-ring applied.  I know the leather will change as well (Sorry again).  Anyways, just trying to keep it real from my experiences.  I am glad you got it figured out for your needs, and I think it's a pretty good idea with the second striker overall.  One thing you may want to try is a section of a nylon bolt in a pocket as the striker.  Now, from my experience, that truly will last a long time.  I'll leave you alone now.  Sorry again.

[PikeP]

Even though this thread isn't about leather faced strikers, I feel I its worth sharing this video...

Its a leather faced striker demo I did nearly 3 years ago...same leather, still at it to this day...I challenge you to record the sound of your rifle, with the microphone placed right next to where the hammer strikes the valve like this video. Its been 3 years or so since I have had a metal or peek striker, but I will never forget the sound they produced upon striking the valve...