More parallel node, Calfee...Case closed.

K

Kathy

Guest
My centerfire friends:

If the "exact center" of the "parallel node" moved for and aft on the barrel as various velocities of ammo were fired, of course the tuner would need constant adjustment to keep the "exact center" of the "parallel node" at the exit of the crown.

But, the "exact center" of the "parallel node" never changes in relation to the crown, no matter what velocity ammo is being used.

Therefore, a tuner of the proper weight, positioned at the proper place ahead of the muzzle, for the configuration of the barrel being used, will stop the muzzle. No further adjusting of the tuner is necessary.

MY dear centerfire friends. I could go on and on, but it's time for me to stop taking up friend Wilbur's valuable forum space with my thoughts on barrel tuners.

Good luck my centerfire friends with your tuner development.

Case closed.

Your friend, Bill Calfee
 
Thank you Bill Calfee

Bill, thanks for all the time you have devoted to this tuner thing and all you have shared with us. I think about what you have been saying quite often throughout the day and I also pay close attention to what others say. We are really getting some good feedback on the subject and I have no doubt that your type of tuner works exactly as you say it does.

Whether or not there is a parallel node that is completely stopped as you say, doesn't matter, who cares; if it works it works!

Prior to Wilbur's visit, I will build a beyond-the-muzzle tuner like you say and we will test both types in the tunnel. It will be a simple matter to machine an add-on attachment for the muzzle and screw my collars onto that rather than the barrel. My stainless steel collars are .250 thick, 1.800 diameter and with the four radial holes drilled for the Tommy bars, weigh approximately 1.5 ounces ea. We will use as many as it takes to 'stop the muzzle' as you say.

Some may interpret this response as admitting that I have been wrong all along, and that is not the case; I am simply saying there are two different ways to approach this thing. The BIG differences between my type tuner and yours are:

1. Weight. If weight is an isssue, then my type tuner would be preferred. (3 ounces vs., 12 to 16 ounces.)

2. With your type tuner, there is a lot of weight hanging out there beyond the muzzle which with some rifles would make them nose heavy.

3. Once installed and adjusted properly, your type tuner requires no further adjustments, while mine requires small adjustments to compensate for changes in atmospheric conditions. Everything is a compromise in some way.

As I have said before, your type of tuner is probably better suited for HV and unlimited rifles, while mine is better suited to the LV and Sporter categories. If weight is of no concern, then certainly your type tuner would be best because it requires no adjustments throughout the day. I have a new stock design that solves the problem of nose heavy rifles and would be a natural for use with your tuners.

I'm sure Wilbur will take some pictures, and give both tuners a good workout and report the findings here on the forum.

Please do not be discouraged by the hard-headedness of centerfire shooters. We are just like everyone else; we have been so bombarded with BS and false claims for so long that we are wary of things that seem too good to be true. With time and patience, we will arrive at the best solution for our particular application. Benchresters are a resourcefull lot and I never cease to be amazed at the knowledge and talent of those who are out there on the cutting edge, advancing the state of the art, and making it happen.

Stay with us, please. :)

Your friend in West Texas,

Gene Beggs
 
New stock for nose heavy rifles

Gene,

Please post a pics of your new stock design for nose heavy rifles. A lot of rimfire guys need one!!:):)
 
Gene,

Get yourself a cheap mechanics stethoscope so you can tap on the barrel and listen. When you have the correct weight in front of the muzzle what you hear right at the muzzle will not have a ring whereas other points behind and in front will have a ring. Before you add the weight you can also find this point well behind the muzzle. It is about 4 inches or so back on my 1000 yd barrels but I can't say how far back it will be on a LV barrel. I set my gun up in the rests to do the ringing just as if on the firing line but I don't know if that matters at all.

I think you may have it right about the out front tuner just may not work out weight and balance wise on a LV rifle.
 
J. Pendergraft said:
Gene,

Get yourself a cheap mechanics stethoscope so you can tap on the barrel and listen. When you have the correct weight in front of the muzzle what you hear right at the muzzle will not have a ring whereas other points behind and in front will have a ring. Before you add the weight you can also find this point well behind the muzzle. It is about 4 inches or so back on my 1000 yd barrels but I can't say how far back it will be on a LV barrel. I set my gun up in the rests to do the ringing just as if on the firing line but I don't know if that matters at all.

I think you may have it right about the out front tuner just may not work out weight and balance wise on a LV rifle.
Click to expand...

J.,

Thanks for the info, I'll do just that.

I have spent many hours 'ringing' barrels. I have suspended them from my thumb and forefinger letting them slide down as I tapped on the barrel noticing where the node was. I have suspended them from strings etc. Very interesting stuff.

I have to thank Dr. Jack Jackson for teaching me how to locate the last node and his method is just as you described above; set the rifle up in the bags and front rest, just as if you were going to shoot it.

Thanks again for the good advice. Keep in touch.

Gene Beggs
 
Gene Beggs

Gene good on you for trying BOTH ways.I think if you try two widely spaced loads and add a weight each time you shoot you can do it in 5 minutes time.
Now I await Wilburs comments.
Lynn
 
Lynn said:
Gene good on you for trying BOTH ways.I think if you try two widely spaced loads and add a weight each time you shoot you can do it in 5 minutes time.
Now I await Wilburs comments.
Lynn
Click to expand...

Thanks Lynn, I'm looking forward to the experiment. I'm sure Wilbur will be very objective in his evaluation of both methods. Keep in touch.

Gene Beggs
 
To change the subject a little, I think that implied in what Bill is saying is that the vibrations used for tuning are driven by something OTHER THAN barrel droop or the firing event.


This agrees with Vaughn. This also takes care of the argument about "after the bullet leaves" etc.......the node is in place long before the bullet gets there.


I think it was Skip Otto???? that did an experiment where he hung a cup of water on the barrel while dryfiring? Found that on the nodes the waterglass had no ripples.....


Or did The Skipper do the trick with tinsel? Where the tinsel vibrated and clumped on the nodes?


Someone also used a penny......where the penny sat was right on Bill's "parallel node".



I think we all need to just accept the term "parallel node" and move on wit' it!!:D Whatever it is, it's stinkin' THERE ;) and the barrel ain't bouncing up and down.


Now Bill, IF this is true, that the driver of the vibration is in the gun.....what are the chances that it's caused by the deflection of the angled firing pin engagement surfaces? :) With the 90* sear and perfectly seated lugs are we gonna' LOSE the overriding vertical vibration?


Or maybe I should ask, Bill what do you think MAKES the vibration that you use for tuning?


thanx





al
 
This agrees with Vaughn. This also takes care of the argument about "after the bullet leaves" etc.......the node is in place long before the bullet gets there. (Alinwa)

I'm not sure how to approach this. Does this mean "after the bullet leaves" is of no importance, or does it mean it is all-important? Everybody seems to want to discuss the "tuner effect" as if it were the effect of weight added affecting a barrel vibrating in some steady state - what most want to describe as a sine, or some similar shaped wave. The problem is; while the dynamic forces of gas pressure, recoil, the bullet, or the firing pin is still being applied, there is NO steady state. Before the bullet leaves all these forces are still being applied, and are constantly changing. I don't know what shape the barrel takes on just before the bullet leaves - who knows it might even have the shape Calfee thinks it does - but I do know IT IS NOT FIXED OR STEADY.

The vibration nearly everyone is talking about, which is described in any physics book, is not what the tuner (weight) is affecting. The physics book's vibration is what occurs AFTER the forces are REMOVED. You do arrive at nodes in one place, and constant frequency, in the the barrel AFTER bullet exit but before that these things are changing - I'm not sure there is any point in the barrel shape before bullet exit that could truly be called a "node", or for that matter you have what the physics book would define as "vibration". The barrel is deflected into some particular shape, at some point in time, while the forces are applied but it is NOT vibrating - actually the book should call it forced motion, that period of time where forces are applied over a small but finite time and then removed over another small but finite time.


Now, making a barrel heavier, or adding weight, or changing length, will affect the deflections caused by any forces (static or dynamic) that act on the barrel. So there can be no doubt that a tuner, since it adds weight and length WILL affect the shape the barrel is in at bullet exit. The problem is determining in what way the tuner is affecting barrel shape, and more important, to what degree this effect is.
 
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pacecil,


"The physics book's vibration is what occurs AFTER the forces are REMOVED."


Yup, that's the idea........I don't think that the gas pressure, barrel droop and passage of the bullet have anything to do with the vibratory effect that's used for tuning. You believe in the forcing thing, not me.

Here are some ideas from back in Aught 4, this subject isn't new.....we've been hashing tuning about on this board for nigh on 12yrs now. This pertickler thread never took off but I tried to list SOME of the effects/affects that had been discussed at that time.

http://www.benchrest.com/forums/showthread.php?t=19183&highlight=action+flex

al
 
Not that I know squat but I struggle to believe that the way a barrel buzzes lightly when hung vertically out of the action and hit with a light hammer has a damn thing to do with the way it vibrates when it sits horzontally screwed into an action that is attached to a fibreglass or wood stock and fired with a pressure starting at 0 and going to a peak of say 70,000psi and the dropping back to maybe 5,000 psi as the bullet uncorks, not to mention the twisting effect of the very rapidly accelerating bullet being spun at one turn in a little over a foot as it travels down the barrel !! Sorry to put all that in one sentence !!

Has anybody considered the imparted vibration frequency matching the natural frequency of the barrel and reinforcing each other so that the barrel really gets to swaying ?? You know, like the galloping girty bridge and how it tore itself apart in 40mph winds simply because the resonant frequency was matched by the wind forces setting up huge movement rather than a light sway ??? Like a kids swing, match the force to the motion and the motion gets bigger and bigger, oppose the motion with a force and the motion dies. Doesn't the tuner simply alter the natural resonant characteristics of the whole stock/action/barrel/tuner assembly such that the areas of least movement can be placed where you want them, ie at the muzzle, the forces being the firing of the round. If the forces applied are simlar enough, like ammo of similar but not identical velocity the muzzle will still be the dead spot. What happens if you then took a really mild reduced load using 5 grains of pistol powder ?? The forces on the barrel setting up the vibration are now very different, will the muzzle now still be more or less stationery and the barrel still tuned for this very different load ?? I'd say no, the barrel is only ever tuned for a range of similar loads that place similar forces on it and set up the vibration similarly enough.

Regardless of the precise vibration pattern and the definitions used, it seems obvious that by using different weights and locations of the weights attached to the barrel you can alter the way that the barrel vibrates. If you can alter it with enough experimentation you can also control it. Therein lies the answer to tuners, controlling the muzzle movement to your benefit, what the rest of the barrel does is just theoretically interesting and makes for good internet chatter.

I'd actually be willing to bet that a tuner placed mid way on a barrel could be used to alter the frequency of the vibration just the same as one placed at the muzzle. The vibration pattern could be altered and set up so that an area of least movement could be placed at the muzzle.
 
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