My problem with the "parallel node"

[Vibe]

I posted an explanation of why I object to the idea of a "parallel node" theory yesterday - and it occurred to me that I don't recall ever posting it in "plain" English before. So I'm reposting it here so some of the more experienced can understand why I've been so adamant about the issue.

I mean there is no consequence to Bill calling something a parallel node or not

Actually there is - which is the point I've been trying to make for 3 years or better. That point being that IF you accept the incorrect notion of some "parallel node" - rimfire accuracy is dead. dead for all ranges other than 50 yards. But when USBR scores of 250-25x become more and more common - which they will - what then? Multiple targets at multiple ranges? Like silhouette? But your "tuner" only works for one range because you've neglected to really notice how it worked - by launching the slower and faster rounds toward a common point of impact. Once you realize that the node at the muzzle is really a pivot of a changing angle - the "tuner" can be designed that will actually BE a tuner - in the same manner that a scope can be zeroed for a given range or the AO on the scope set. The click adjustment will not be for the "sweet spot" at 50 yards, but for the "sweet spot" at what ever range you happen to be shooting at.

But as soon as the "parallel node" concept goes unchallenged - all that dies.
It's about advancing rimfire accuracy...not just advancing rimfire accuracy at ONLY current match ranges.

I guess it's more for those who also think that "Close enough" really isn't.

 

[Jetmugg]

Bravo, Vibe. You are a model of patience and understanding.

Using the correct terminology is not just a matter of semantics. Specific words carry specific meanings and connotations. Words like "parallel", "node", "stopped", and "downforce" do not have some kind of arbitrary, user-defined meaning. In this case, the way these words are used is intended to define a particular phenomena (how a rifle's barrel can be tuned). Without a clear understanding of the terms, it is impossible to describe in detail what is really going on.

You are 100% correct that as soon as the incorrect definitions go unchallenged, that the underlying concepts become hazy and subject to mis-interpretation.

I noticed that you have been the object of some derision for not accepting the incorrect and user-defined definitions of the words listed above. That is quite ironic, that the person who wishes to apply the terms correctly is ridiculed for not using the improper definitions. I wonder why the person who is actually using the improper terms is not subject to the same kind of popular pressure to correct his usage of the terms. In order to understand and improve rimfire accuracy or precision, everyone needs to have the same language to speak. The standard should be for everyone to learn the correct usage, not for the correct folks to adopt the imaginary usage.

Your description of tuning for various ranges may very well have some applications in the silhouette shooting world, particularly out at 77 and 100 meters, where the elevation changes due to velocity differences are more pronounced. I can envision people adjusting their tuners for each animal in the same way they adjust their scopes for each animal.

Keep up the excellent work, Vibe.

SteveM.

 

[mks]

I posted an explanation of why I object to the idea of a "parallel node" theory yesterday - and it occurred to me that I don't recall ever posting it in "plain" English before. So I'm reposting it here so some of the more experienced can understand why I've been so adamant about the issue.



I guess it's more for those who also think that "Close enough" really isn't.

Vibe,
Stick with it, man. Sometimes right is right, and wrong is wrong.

Keith

 

[Peter Armstrong]

With all these theories about the gun needing to be tuned for each distance, could someone explain to me how I manage to get my barrels to shot at multiple distances without changing the tuner? I’m not looking for an argument I’m just asking is there a way of explaining it?

Unlike some I’m not going to cut out a group on a target and say look at this, I can backup what I’m saying from national championship results and I’m not taking about one barrel, I have 3 match barrels a Border, Broughton and a Lilja and all will do the same sort of thing. The Border I shot in a international match in New Zealand last month and shot a 744.49 in a strong fishtailing head wind, that barrel at the group national in extreme wind shot (at the same tuner setting) 100m groups of .45 .752 .433 1.356 .709 for a .74 agg ,the 4th group I got caught in a shift down range and it was fault not the guns.

As I said I’m not looking for an argument, but either all these gold medals and national records I’ve picked up over the last few years are imaginary, or there is a theory to explain it, or the theories about the gun needing to be tuned for each distance is wrong.

Peter

 

[Lynn]

Vibe
Your looking at a FEA modeling of 0.003 seconds of a barrels vibration pattern.
Do you honestly believe Bill Calfee is looking at only 0.003 seconds of a barrels vibration in his testing? I think Wallace Smallwood(Beau) has posted he showed the experiment to an engineer who watched it and in general said Yep I understand how the ordinary bloke could call it a parallel node.If you ever get the chance to work in the high tech industry were you might run across 125 technicians performing tuning and testing you would be amazed as to how they describe what they are seeing.I take the Calfee explanation of what he is seeing at face value as he has repeatadly stated you can call it what you want.
Your only looking at this from a 0.003 second point of view and that is were the rub lies.If the barrel tuner is out of adjustment what would we see at the 1 second mark versus a tuned rifle at the 1 second mark? I doubt Bill is looking only at the incident direction of the wave like You and Varmint Al keep preaching.I would expect him to be looking at a much longer period of time and when the wave reflects back upon itself or all the harmonics come into play he notices something he calls a parallel node.
There are many wave analysis websites online and when the time frame is expanded beyond 0.003 seconds you might even see a parallel node? Ever seen a square wave? Was it truly square?
Waterboy
P.S.
"As strange as it may seem, any repeating, non-sinusoidal waveform is actually equivalent to a series of sinusoidal waveforms of different amplitudes and frequencies added together. Square waves are a very common and well-understood case, but not the only one."
Vibe try explaing this statement to anyone on this website and see what happens.I have tried.

 

[Joe Friedrich]

With all these theories about the gun needing to be tuned for each distance, could someone explain to me how I manage to get my barrels to shot at multiple distances without changing the tuner? I’m not looking for an argument I’m just asking is there a way of explaining it?

Unlike some I’m not going to cut out a group on a target and say look at this, I can backup what I’m saying from national championship results and I’m not taking about one barrel, I have 3 match barrels a Border, Broughton and a Lilja and all will do the same sort of thing. The Border I shot in a international match in New Zealand last month and shot a 744.49 in a strong fishtailing head wind, that barrel at the group national in extreme wind shot (at the same tuner setting) 100m groups of .45 .752 .433 1.356 .709 for a .74 agg ,the 4th group I got caught in a shift down range and it was fault not the guns.

As I said I’m not looking for an argument, but either all these gold medals and national records I’ve picked up over the last few years are imaginary, or there is a theory to explain it, or the theories about the gun needing to be tuned for each distance is wrong.

Peter

Peter,

First off congrats on the great shooting. I feel you are not going to get the answer you are looking for. It is what it is and that should be good enough because it was good enough to accomplish what you have done. As you can see the thread is already off topic and turning ugly.

Regards,
Joe

 

[jGEE]

With all these theories about the gun needing to be tuned for each distance, could someone explain to me how I manage to get my barrels to shot at multiple distances without changing the tuner? I’m not looking for an argument I’m just asking is there a way of explaining it?

Unlike some I’m not going to cut out a group on a target and say look at this, I can backup what I’m saying from national championship results and I’m not taking about one barrel, I have 3 match barrels a Border, Broughton and a Lilja and all will do the same sort of thing. The Border I shot in a international match in New Zealand last month and shot a 744.49 in a strong fishtailing head wind, that barrel at the group national in extreme wind shot (at the same tuner setting) 100m groups of .45 .752 .433 1.356 .709 for a .74 agg ,the 4th group I got caught in a shift down range and it was fault not the guns.

As I said I’m not looking for an argument, but either all these gold medals and national records I’ve picked up over the last few years are imaginary, or there is a theory to explain it, or the theories about the gun needing to be tuned for each distance is wrong.

Peter

I’m not looking for an argument I’m just asking is there a way of explaining it?

Yes there is....... your shooting very good ammo that the speed changes less than 10 fps. I don't think you would be a national champion unless you had really good ammo.

Tuning is for making different speed ammo shoot in the same hole -maybe 20 or 30 fps difference. Probably just one answer... joe

 

[Peter Armstrong]

Peter,

First off congrats on the great shooting. I feel you are not going to get the answer you are looking for. It is what it is and that should be good enough because it was good enough to accomplish what you have done. As you can see the thread is already off topic and turning ugly.

Regards,
Joe

Joe,
I agree, it is what it is and I never expected to get a proper answer.

That Border with Lapua is very sweet combination.

Peter

 

[Peter Armstrong]

Yes there is....... your shooting very good ammo that the speed changes less than 10 fps. I don't think you would be a national champion unless you had really good ammo.

Tuning is for making different speed ammo shoot in the same hole -maybe 20 or 30 fps difference. Probably just one answer... joe

Joe,
Some people seem to think I have special ammo and special barrels, I don’t, I do have magical wind probes but that’s another story. But I have no idea what the spread of the Midas + I used in New Zealand is, I haven’t tested it, if they keep dropping in the X ring that’s all I need to know. In the past I’ve won at nationals shooting 900B, Olimpic-R, R100, R50, X-Act and Midas+ with all types of spreads.

Peter

 

[hulk]

Lynn,

"I take the Calfee explanation of what he is seeing at face value as he has repeatadly stated you can call it what you want."

I will take this explanation at face value as well.

Now, if this quote sums up this theory, "A proper weight, placed at the proper location in front of the crown, will stop muzzle oscillations completely, thereafter no further adjustment of the muzzle device is necessary.", how do you reconcile the observations that faster velocity ammo and slower velocity ammo will have the same POI?

Unless the laws of physics and gravity have been suspended, help us understand how this can occur.

 

[Vibe]

Joe,
I agree, it is what it is and I never expected to get a proper answer.

That Border with Lapua is very sweet combination.

Peter

Actually I think you did get your "proper answer". With good skill, good equipment and good ammo - the tuner really doesn't have to "work" very hard. But If the larger 3 groups were due to vertical (one was "blown out due to wind", so I can't tell how much vertical there was), or if any of the groups were large due to vertical - then possibly a range adjusted tuner cold help you do even better. A 50 yard tuner will even help most yardages, simply by removing some of the causes of initial yaw - but a range specific tuner will also reduce the vertical - at that range. Wouldn't you rather have agged 0.35 even more than the great score you did score?

 

[B. Harvey]

With good skill, good equipment and good ammo - the tuner really doesn't have to "work" very hard.

I was told by a top competitor that... "if you have the absolute best ammo for your rifle, it makes no difference if you are tuned, untuned, or don't even have a tuner!"

 

[Lynn]

Hulk
Bill Calfee is descriing exactly what he is seeing with his own two eyes.Vibe is describing 0.003 seconds of a barrels vibration pattern as seen by testing equipment and computer modeling.He is doing that because you can't see a rifle barrel vibrate with the naked eye.
If you watch the antenna on a pickup truck while your driving down a bumpy road that is what Bill is seeing and describing.He gave everyone here a simple test to do with a piece of welding rod several years back.
In Vibes example of what is taking place when the bullet exits you or anybody else won't be able to see what Bill is describing because of the time difference between the two observations.
The big question everyone should be looking for a answer to should be how do we go from a specific ammo tuned for our rifle to Bill's Killer tuned set-up were no further tuner adjustment needs to be made.
If you simply add weight until the vertical is gone or adjust the tuner until the vertical is gone that works great but only on that batch of ammo at that time.

In electronic waves there are 3 places were you can tune a wave.You can add a bunch of capacitance(weight) on one side of the ideal location or Youi can add a bunch of capacitance(weight)on the other side of the ideal location and you will get what your after.If you add the right amount of capacitance(always less than on either side) directly centered between those two points you accomplish the best tune with the least amount of capacitance(weight).
In electroonics they use sophisticated equipment to find this ideal spot.
On rifle barrels we try and decipher what Bill is trying to tell us and hopefully come up with that ideal location.
I would hope a guy with Vibe's brain power would tune a barrel up to get rid of the vertical then tell us how much further out the ideal location was.We could then reduce the amount of weight slightly and have our tuners well centered up.
Nothing on earth is technicaly stopped so arguing that concept is a huge waste of time in my opinion.
Waterboy

 

[Vibe]

Hulk
Bill Calfee is descriing exactly what he is seeing with his own two eyes.Vibe is describing 0.003 seconds of a barrels vibration pattern as seen by testing equipment and computer modeling.He is doing that because you can't see a rifle barrel vibrate with the naked eye.
If you watch the antenna on a pickup truck while your driving down a bumpy road that is what Bill is seeing and describing.He gave everyone here a simple test to do with a piece of welding rod several years back.
In Vibes example of what is taking place when the bullet exits you or anybody else won't be able to see what Bill is describing because of the time difference between the two observations.
The big question everyone should be looking for a answer to should be how do we go from a specific ammo tuned for our rifle to Bill's Killer tuned set-up were no further tuner adjustment needs to be made.
If you simply add weight until the vertical is gone or adjust the tuner until the vertical is gone that works great but only on that batch of ammo at that time.

In electronic waves there are 3 places were you can tune a wave.You can add a bunch of capacitance(weight) on one side of the ideal location or Youi can add a bunch of capacitance(weight)on the other side of the ideal location and you will get what your after.If you add the right amount of capacitance(always less than on either side) directly centered between those two points you accomplish the best tune with the least amount of capacitance(weight).
In electroonics they use sophisticated equipment to find this ideal spot.
On rifle barrels we try and decipher what Bill is trying to tell us and hopefully come up with that ideal location.
I would hope a guy with Vibe's brain power would tune a barrel up to get rid of the vertical then tell us how much further out the ideal location was.We could then reduce the amount of weight slightly and have our tuners well centered up.
Nothing on earth is technicaly stopped so arguing that concept is a huge waste of time in my opinion.
Waterboy

Well you're getting closer.
I'm looking at three factors (I think) - Mass, moment about the node, and moment of inertia. Mass to fix the "first order", Moment about the muzzle to fix the "2nd order", and moment of inertia to adjust the "3rd order". I'm using the terminology for a standing wave even though the actual forms are variable as a function of the variable stiffness.

 

[Lynn]

Vibe
If a guy had a machine rest with a regular barrel on it he could put a dial indicator on the muzzle and adjust the vertical out of his groups while simutaneously watching the chronograph.This should allow you to see how much farther up the barrel was for the slower shot than the faster shot and you could calculate out how much each movement of the tuner changed the vertical spread in a real world test.
I tried this with an unlimited gun weighing 75 pounds in a one piece rest system weighing 44 pounds with an additional 125 pounds of lead shot bags on it.It didn't work at all for me.
I am still well tuned for one part of the day just not for the long haul.
Waterboy

 

[hulk]

Lynn,

Must be the cold weather, I am confused.

"Nothing on earth is technicaly stopped so arguing that concept is a huge waste of time in my opinion."

I agree with your point. However, this conflicts with Bill's theory, "A proper weight, placed at the proper location in front of the crown, will stop muzzle oscillations completely, thereafter no further adjustment of the muzzle device is necessary."

Where do you stand?

 

[Tom C.]

Lynn,

Must be the cold weather, I am confused.

"Nothing on earth is technicaly stopped so arguing that concept is a huge waste of time in my opinion."

I agree with your point. However, this conflicts with Bill's theory, "A proper weight, placed at the proper location in front of the crown, will stop muzzle oscillations completely, thereafter no further adjustment of the muzzle device is necessary."

Where do you stand?

Uhoh Lynn finally gets it.

 

[mks]

Vibe
Your only looking at this from a 0.003 second point of view and that is were the rub lies.

Lynn,
That's it exactly. Steady state vibration, with its "nodes," "anti-nodes" and "modes" is not relevant to such short times. By the time these steady vibration patterns have developed, the bullet is long gone. It's like trying to figure out how to keep the horse in the barn by studying how the gate swings after he is already gone. It would be nice if it were kinda, sorta, maybe related, but it isn't.

Cheers,
Keith

 

[Vibe]

Vibe
If a guy had a machine rest with a regular barrel on it he could put a dial indicator on the muzzle and adjust the vertical out of his groups while simutaneously watching the chronograph.This should allow you to see how much farther up the barrel was for the slower shot than the faster shot and you could calculate out how much each movement of the tuner changed the vertical spread in a real world test.
I tried this with an unlimited gun weighing 75 pounds in a one piece rest system weighing 44 pounds with an additional 125 pounds of lead shot bags on it.It didn't work at all for me.
I am still well tuned for one part of the day just not for the long haul.
Waterboy

Any mechanical indicator is going to exhibit way too much hysteresis and "bounce". I was thinking more along the lines of an array of laser displacement sensors like these
http://www.keyence.com/products/measure/laser/lkg5000/lkg5000.php
http://www.keyence.com/products/measure/laser/ljg/ljg.php
and a wave form viewer like Audacity or similar. We need to be able to see not only the change in position, but that change in respect to time.

 

[Vibe]

Lynn,
That's it exactly. Steady state vibration, with its "nodes," "anti-nodes" and "modes" is not relevant to such short times. By the time these steady vibration patterns have developed, the bullet is long gone. It's like trying to figure out how to keep the horse in the barn by studying how the gate swings after he is already gone. It would be nice if it were kinda, sorta, maybe related, but it isn't.

Cheers,
Keith

Well it is "kinda, sorta, maybe related" , but you're correct - that's about as close as it comes. The barrel is not in stready state at the point the bullet leaves, but the barrel is still behaving along vibrational lines, so the terms are not completely incorrect - a bit fuzzy? Yeah, I concede that....but a heck of a lot closer than "parallel" and "stopped".