Testing new discovery

[grand-galop]

I am beginning to think the reason our airguns shoot better once we find the upper limit, and then turn then down a bit, is that vibration Kinfemaker has revealed to us.


Roachcreek

Lany!  I'm not so sure about this one... Ted Bier has done some more pushing with his FX IMPACT and he got excellent excellent results at 960 fps in 25 cal.

[Lani52]

Perhaps, but every gun is different.

Heaving said that, you will read time and time again about  air gunners dropping down 5 or 10 FPS from maximum velocity and getting better accuracy, at least that is what being on these forums for 10 years has taught me.

Now my Haley 257 Scandalous and Ranger 45 did better full throttle, but perhaps slugs are different as all guns and people are different.

And Lani is my lovely wife who signed me up for this forum.

Roachcreek

[Mole2017]

...using a solid mass mounted on springs, or a pendulum, or a glob of peanut butter that must be reapplied precisely after every shot.... is dragging the original idea soooooooooooo far off course we are just getting deeper into the woods without a compass, or even a trail of breadcrumbs to follow.... It is not my intention to discourage innovation and development, far from it.... but realistically if you have an idea to try, get out and try it, instead of suggesting something you haven't tried.... JMO....

Bob

Don’t misunderstand the peanut butter idea, I'm just trying to talk through the physics as some of the other ideas come out, especially as there is a lot of uncertainty about how it works, e.g. my first post about slosh vs whatever and the relationship of viscosity and density of the "ingredients", like some of what you just said. Knife's application of a device originally designed for archery is successful, but we don't yet know why.

We're know it isn't operating like the barrel weights. And, as you observed, some are seeing success and others aren’t. So we're just trying to get the principles that would guide any tuning. The peanut butter idea is just something from outside of the box, but only because it is perhaps operating on different principles.

To help us on that journey, here’s a review of the state of the art (not in chronological order):

1. Bob posted his version, replies 220 and 311 in this thread which detailed how much lead shot, oil and air space he used. It wasn't as effective as others have seen (reply 297), but he gives details of its construction--we need others to fill in the details of what they’ve tried, like Don asked back in reply 225.


2. Denis built one off the end of the barrel/shroud (reply 138 and revised in 261) that was about the same as one Bob also proposed (reply 251), which worked well for him but is out for testing by others too.


3. Then there was Robert's design (reply 203, with details in reply 216), which was successful with steel BBs instead of lead (reply 205).



4. Tim did a version with some details (reply 219), but it didn't help on the rifle he tried it on (reply 262).



5. Alain is doing something along the sprung mass absorber, I think (reply 335 and 338), but it didn't work out and is under revision.


6. And of course Knife's version (reply 130), which is just a repurposed absorber from archery, correct? He also tested his against a solid mass of the same weight and a limb saver, ruling out those designs as not nearly as effective as this one. If I follow correctly, Don was also looking at a similar device and sort of gives some details of the construction in replies 242 and 273.


7. Charles also repurposed an archery device for his version (reply 272), which also worked well. He mentions it is oil filled, and it looks like Don has determined there is some sort of powder in with the oil in the versions he has looked at (reply 273). Does anybody else know what is in these things?


If anybody does that peanut butter, be sure to get a picture! But seriously, Don was inviting people to post specifics of any devices they test. If I missed one, please remind us. I wish I had more time to actually do something rather than just think about it, so good luck to everyone!

[Mole2017]

Well, shoot, I had the pictures in preview and now I don't see them when I posted it...stay tuned, I'll try to get that fixed.

...OK, all fixed. I had drafted the post in Word, which stuck HTML flags on my links inside of the IMG flags I was intending to use. It worked on my computer in review, but failed when posted. So, watch out if you draft long replies in other editors...

[robertr]

 Update on design #3, still needs tinkering. Results were not consistent with the groups I posted so adjustments will have to be made, I think change out the bb's for lead and test again.

[Nvreloader]

Mole 2017

Thanks for the photo's,

I have photo's of my MAD device, on my Android phone,

But I can't figure out how to post photo's to our site, I have tried until I am Blue in the face,
and then get mad and just forget it etc.

Thank you,
Don

[KnifeMaker]

I am having fine results with many different bullet. Pellets as well now.


Now if I could just figure out the twist I need, i would be set.


I need to write Mr. Bob. .


I need to make a smaller and lighter version and test. Testing different ideas is what I enjoy.


I very much appreciate so many here jumping in and testing different takes on the concept. It indeed does have the possibility of being a game changer for those of us  who are accuracy nuts.


More shop time tonight on another idea. LOL


Knife/Mike

[darkcharisma]

You should focus on casting 10k out of the mould I sent while you have shop time, Mike. 1 more month will go by fast. 😁

[BackStop]

I am having fine results with many different bullet. Pellets as well now.


Now if I could just figure out the twist I need, i would be set.


I need to write Mr. Bob. .


I need to make a smaller and lighter version and test. Testing different ideas is what I enjoy.


I very much appreciate so many here jumping in and testing different takes on the concept. It indeed does have the possibility of being a game changer for those of us  who are accuracy nuts.


More shop time tonight on another idea. LOL


Knife/Mike

I know you are going to start to working on what I asked about.

A device that calms my shaky hands!  (chuckle) 

[KnifeMaker]

I am having fine results with many different bullet. Pellets as well now.


Now if I could just figure out the twist I need, i would be set.


I need to write Mr. Bob. .


I need to make a smaller and lighter version and test. Testing different ideas is what I enjoy.


I very much appreciate so many here jumping in and testing different takes on the concept. It indeed does have the possibility of being a game changer for those of us  who are accuracy nuts.


More shop time tonight on another idea. LOL


Knife/Mike

I know you are going to start to working on what I asked about.

A device that calms my shaky hands!  (chuckle) 

OK, may release lead shot filled weighted gloves. There ya go!

[BackStop]

I am having fine results with many different bullet. Pellets as well now.


Now if I could just figure out the twist I need, i would be set.


I need to write Mr. Bob. .


I need to make a smaller and lighter version and test. Testing different ideas is what I enjoy.


I very much appreciate so many here jumping in and testing different takes on the concept. It indeed does have the possibility of being a game changer for those of us  who are accuracy nuts.


More shop time tonight on another idea. LOL


Knife/Mike

I know you are going to start to working on what I asked about.

A device that calms my shaky hands!  (chuckle) 

OK, may release lead shot filled weighted gloves. There ya go!

And once again, how am I going to shoot with my arms weighted down at my sides? (chuckle)

Actually, after my initial pain from pumping the Freedom (about 1000 to 1200 times in about 4-5 hours), I have not had that problem again.

However, I don't shoot 300 pellets in a session anymore.  I am slow, but I am capable of learning.

[KnifeMaker]

 

[grand-galop]

Guys!!  After my last session of shooting yesterday, I unmounted my device and analyze if it was a flaw in design.. Nothing is wrong with it..  But by playing with it on the barel, I think I may have find another path where it may  apply.. My conception is leaning towards RECOIL MANAGEMENT in big bore application.  What we are chasing for is eliminating the whiplash of the barrel or having a CONTROLLED HARMONIC with the barrel..  The yaw and pitch is what make the projectile unpredictable... Before I go all in with my discovery, I want to ask other thinkers and experience members what is their take on it...  It could attach to a barrel weight or a LCD as an ANCRE POINT.... The slip over sleeve is empty and we could use the opposite end of the sleeve and glue a ruber washer that would slip over the barrel to control the lateral and vertical movement.. The sleeve could be slide in and out for controlling different harmonics and power levels... The only CRITICAL component in this build is the quality of rubber used.. Too hard the type of rubber, harsher could be the harmonic.. Too soft could lead to no control at all.. For now I have 2 type of rubber I want to use...  The rubber mat  I use at my work bench is cushy and return to it's original form pretty quickly..  The other type was recoup from a job site and was red and they were placing it between the creat and the electronic box but it is just a bit harder.  Let me know your taught..

[BackStop]

Guys!!  After my last session of shooting yesterday, I unmounted my device and analyze if it was a flaw in design.. Nothing is wrong with it..  But by playing with it on the barel, I think I may have find another path where it may  apply.. My conception is leaning towards RECOIL MANAGEMENT in big bore application.  What we are chasing for is eliminating the whiplash of the barrel or having a CONTROLLED HARMONIC with the barrel..  The yaw and pitch is what make the projectile unpredictable... Before I go all in with my discovery, I want to ask other thinkers and experience members what is their take on it...  It could attach to a barrel weight or a LCD as an ANCRE POINT.... The slip over sleeve is empty and we could use the opposite end of the sleeve and glue a ruber washer that would slip over the barrel to control the lateral and vertical movement.. The sleeve could be slide in and out for controlling different harmonics and power levels... The only CRITICAL component in this build is the quality of rubber used.. Too hard the type of rubber, harsher could be the harmonic.. Too soft could lead to no control at all.. For now I have 2 type of rubber I want to use...  The rubber mat  I use at my work bench is cushy and return to it's original form pretty quickly..  The other type was recoup from a job site and was red and they were placing it between the creat and the electronic box but it is just a bit harder.  Let me know your taught..

I'm not sure if I am following you exactly, but I did have a noticeable improvement in my groups when I mounted my DIY slip-on LDC (duct tape on the end of the shroud is involved for snug fit) on my recently purchased Nova Vista Freedom .177.  Not a huge improvement, but noticeable.  I also noticed that the "ping" I was hearing from the hammer striking the valve went away.  I guess I just got lucky, but the slip on LDC seems to have dampened the harmonics of the barrel even though it is only attached to the shroud.

Anyway, like I said... I may not be following your idea and what I am saying is anecdotal, so take it for what it is worth.

Kerry

[grand-galop]

Kerry!!  What I am saying is, WE might have looking at the wrong direction..  If you look at all the devices used,  they ALL ACT AS THE MERCURY TUBES they use the burry in the butt stock in the 80's for better recoil management because it interact in the same AXIS AS THE BORE... We are chasing the harmonics that occurred at 90* of the axis..

 All the SLUSH MECHANICAL DEVICES are active in the same axis of the bore but due to their added weight, they might act as a vertical damper....

The amplitudes of the harmonic are manageable with a BUMPER like the rubber washer that hold the desired weight to counters the amplitude to a minimum level..

[BackStop]

Kerry!!  What I am saying is, WE might have looking at the wrong direction..  If you look at all the devices used,  they ALL ACT AS THE MERCURY TUBES they use the burry in the butt stock in the 80's for better recoil management because it interact in the same AXIS AS THE BORE... We are chasing the harmonics that occurred at 90* of the axis..

 All the SLUSH MECHANICAL DEVICES are active in the same axis of the bore but due to their added weight, they might act as a vertical damper....

The amplitudes of the harmonic are manageable with a BUMPER like the rubber washer that hold the desired weight to counters the amplitude to a minimum level..

I understand.  And that actually might explain why my slip on LDC helped.  It may have stabilized that 90° harmonic, even though it is mounted on the shroud.

It is simply a 1 inch PVC pipe, but I may have gotten lucky with the length.

In any case, I think I agree with your assessment of what is going on, yet, I don't have the capability to make and test these devices, so I will defer to those who can and do.

I think the way  the MAD device has been developed so far may indeed help the Crosman Fire/F4 that I have retired.  However, the Freedom shoots so well for me, I just don't have the desire

to take the Fire back out right now to test it with such a device.

Kerry

[jarmstrong]

Knife, I’m all in. Like some, I was somewhat skeptical at first, but not now. I had to try your discovery for myself, and was blown away. Wow!
We are having almost constant rain, so I set an ironing board (best I could come up with) on my front porch with a heavy sand bag on top as a bench. Set out a target at 50 yds. Shot several 5 shot groups with my .22 FX Dreamlite. The heavy bag helped steady things up. Still it took several groups for me to settle in. From the picture, the three bottom groups I shot without your discovery. I do general do better, usually about .4”-.5” but as I said it took a while to get settled in. The top two groups I shot with my version of your discovery, I came up with #1 .275” center to center; POI shifted quite a bit low right. #2 I gave a few clicks up and left same POA .245” center to center. That is the best groups I have ever shot with anything! Amazing!  I ran out of time but will certainly be doing more experimenting. Can't wait to see what becomes available.
Specs as follows: The stabilizer I used is from my @=S+S%^$# days in the 1990s, and is oil (?) filled. It did a good job, with an extension of taming a short little Mathews hunting bow I had.  No markings on it, so brand or model is a mystery.
1” dia. steel tube with aluminum end caps
3 3/16” Long
3.2oz wt.
The bracket I made from a steel bar. I drilled and tapped it 1/2”x20 to fit my Dreamlite barrel threads. I put an o-ring on barrel threads before screwing on and snugging up on the barrel. I drilled the bar 1/4” and used a 1/4” screw to mount the stabilizer on the bar.
4.8 oz. Total wt. for mount and stabilizer
.22 FX Dreamlite
18.13 gr. JSBs straight out of tin
900 fps
Light rain falling 0 wind

Grand-galop is thinking along the same lines I am, the radial vibration is what is the problem. In my earlier life I saw an anti vibration setup for an vertical elec motor on a well , have an offset weight on a rod parrallel to the motor, which would swing out of phase with the primary vibration
the set up like the above quote looks to be the best at reducing the and is in line and fixed at one end only,allowing the bow damper to do its thing. I am waiting for my ebay bow damper to arrive, but instead of threading it on the barrel, I make the adapter to be a slip fit on the barrel and design it to clamp on.
It will be like a drop block with the bow damper under and parallel to the donnyfl Sumo
Dang it, go to page 14 to see Hoople's photo for his mount method

[rsterne]

Perhaps I am misunderstanding what you are trying to build.... but sliding a weight along the barrel is basically trying to change the harmonics so that the pellet arrives at the muzzle when it is pointing in a consistent direction.... In other words, you are tuning the barrel for a specific pellet and velocity, exactly what the rimfire benchrest shooters do.... This harmonic tuner I made does the same thing....



The threaded steel sleeve is screwed onto the barrel and tightened in place.... The brass weight moves back and forth to tune the vibration of the barrel to your pellet and velocity.... It is 28 TPI, so it only moves 0.003" for each "hour" (30 deg.) you turn it.... I have not had the opportunity to do much testing, but I understand movements as small as 0.002-0.010" can make a big difference in group size, depending on the weight you are moving back and forth....

The difference between moving a solid weight and using a mass of "lead slush" (or mercury) is that I think the latter would have a wider "sweet spot", and be less critical on placement.... The reason I suggest that, is that if with one pellet and velocity the barrel is not moving much, the damper effect would be small.... However, with another pellet and velocity, that is not shooting well because the barrel is whipping around, the damper should have more effect.... That, logically, to me would be why it seems to work better on improving "poor" bullets or pellets.... The moving shot "damps" the vibration, rather than "tuning" it to a given frequency like moving a solid weight does.... JMO....

I have been giving more thought to the viscosity of the oil in the damper, and I think the "thinner" it is, the better.... We are dealing with a very short duration event here, the pellet is only in the barrel for about 3 mSec (0.003 sec.)…. At 850 fps, it travels the last 2" of the barrel in just 0.2 mSec.… As viscosity increases, the fluid takes longer to move for a given force applied to it.... Think about dropping a single #8 shot onto grease, heavy gear oil, light hydraulic fluid, or water.... It might take days for it to make a dent in the grease, a minute or more to drop an inch through the heavy gear oil, a second or two through the light hydraulic fluid, and almost no delay through the water, even though the water is more dense (ie oil or grease float on water)….

Mercury is probably the ideal fluid, because it is nearly twice as dense as lead shot (13.6 vs. 7.0), so the same weight takes up half the volume.... In addition, it's viscosity is only 1.5 (water being 1.0), whereas a light hydraulic oil (like the power steering fluid I used) is about 80, and 30W motor oil is about 350.... Simply put, for a given force applied, the lighter the oil, the faster the lead shot can respond to the barrel vibration.... and it doesn't have long to respond during the 0.0002 sec. it can affect the flight of the pellet.... Mercury can respond even faster....

Bob

[grand-galop]

Bob!  Everything you have mentioned above is right!!!  That being said, the viscosity damper in the tube MAY ACT vertically but has NOWHERE TO GO LATERALLY.. TO BE PERFECTLY EFFICIENT , it would have to be placed PERPENDICULAR to the bore axis...  My idea of the rubber washer glued to the sleeve is to have the DAMPENING EFFECT  to have a higher VISCOSITY  DAMPENING and any sound attenuation possible in the same device …. The TUNING could be achieve with just sliding the device along the  for flexibility... I WOULDN'T put this device on a power burner because of the degradation of the material use...  So that device could be sold EXCLUSIVELY TO AIR RIFLE...


Just a hint for Donny.

[Nvreloader]

Bob
I know from what little bit I have used my MAD device (Mercury filled, 14.3 gr pellet @ 900 + fps)
The best accuracy when the MAD is placed right under the end of the bbl (air stripper), on the Gauntlet shroud.

I have started this MAD device at the breach end (was placed at 90* to the bbl) until I got past the air tank,
and then I could hang it straight under the bbl, and slide towards the muzzle in 1" increments,
there was a bigger change in accuracy the closer I got to the muzzle end.

Have you watched the video of the Mercury reactions?  I am not sure what language it is (French?),
it is quite interesting when the vibration rates is changed etc.
https://www.gatewaytoairguns.org/GTA/index.php?topic=157680.180, pg 10, post # 191.
Could this be what is happening to a lesser degree as the pellet/slug is passing down the bbl?

I have some heavy weight pellets coming, and will test my MAD device with them etc.

I am also in the belief that Mercury is the best material to use for it's reaction time,
plus the smallest package possible etc.

Tia,
Don