E
Edwin D
Guest
Al,
I remember it well.
I remember it well.
S
steve b.
Guest
Al...,
I wish I knew half of what you've forgotten, excellent explanation. Thanks!
I wish I knew half of what you've forgotten, excellent explanation. Thanks!
K
Kathy
Guest
Friend Mike S
Friend Mike S
My friend, thank you for your post #11.....now you're thinking my friend....
The exact center of the "parallel node" never gets closer, nor, further from the crown........as muzzle vibrations increase, or, decrease.......MIike, this is a fact.....
Friend Mike, don't confuse the fact that becasue the center of the parallel node never changes its location in relation to the crown, as vibrations increase or decrease, that we can't move it.....we CAN move the parallel node itself......with a proper muzzle device...
And Mike, once we do move the center of the parallel node to the crown, no further adjustments are ever necessary, no matter how much muzzle vibrations change...BECAUSE ITS CENTER NEVER CHANGES ITS RELATIONSHIP TO THE CROWN.... It's simply awesome my friend.
Again Mike S, thank you for thinking my friend....
Now we're getting some where my friends..
Your friend, Bill Calfee
Friend Mike S
My friend, thank you for your post #11.....now you're thinking my friend....
The exact center of the "parallel node" never gets closer, nor, further from the crown........as muzzle vibrations increase, or, decrease.......MIike, this is a fact.....
Friend Mike, don't confuse the fact that becasue the center of the parallel node never changes its location in relation to the crown, as vibrations increase or decrease, that we can't move it.....we CAN move the parallel node itself......with a proper muzzle device...
And Mike, once we do move the center of the parallel node to the crown, no further adjustments are ever necessary, no matter how much muzzle vibrations change...BECAUSE ITS CENTER NEVER CHANGES ITS RELATIONSHIP TO THE CROWN.... It's simply awesome my friend.
Again Mike S, thank you for thinking my friend....
Now we're getting some where my friends..
Your friend, Bill Calfee
jackie schmidt
New member
This is getting strange!!
Varmint All has come on saying that all of this discussion is based on a false premise, and Bill Calfee keeps jumping up and saying "eureka, I have found it".
Weird Science............jackie
Varmint All has come on saying that all of this discussion is based on a false premise, and Bill Calfee keeps jumping up and saying "eureka, I have found it".
Weird Science............jackie
Lawrence W.
Member
Go to Al's web site and check out his modeling for centerfire and his modeling for rimfire you will see a dramatic difference between the two models. The bullet exit time for centerfire is always somewhere around the 1st peak or before the barrel has a chance to settle in to its natural vibration mode. The bullet exit time for the much slower 22 rimfire appears to be somewhere during the the 2nd sine wave or once the barrel has had a chance to settle into its natural barrel vibration. I can see and understand where the slower moving rimfire benefits from the "stopped muzzle" tuner simply because the bullet is still in the barrel when the natural vibration takes over after the initial explosive vibrational peak, while the much faster centerfire simply cannot benefit from the "stopped muzzle" tuner simply because the bullet has already left the barrel before the natural vibration has a chance to establish itself.
Very simply, the "stopped Muzzle" may well work for rimfire but physics say it can't work for centerfire!
Correction- If you slowed your 6PPC down to around 1,100 FPS, you too may experience the benefits of a "stopped muzzle" tuner.
Lawrence Weisdorn
Very simply, the "stopped Muzzle" may well work for rimfire but physics say it can't work for centerfire!
Correction- If you slowed your 6PPC down to around 1,100 FPS, you too may experience the benefits of a "stopped muzzle" tuner.
Lawrence Weisdorn
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Boyd Allen
Active member
I have used a tuner, (on a 10.5# 6PPC), and have reported favorably on the results, having shot the same barrel extensively before the tuner was fitted, but I know that any explanation of why that is is to a certain degree conjecture. Even computer simulations are not perfect, depending on the accuracy of modeling, but I tend to favor Varmint Al's work in this area over pure imagination.
Of course one does not need to have a tuner to tune a CF rifle, or to do well in matches, as there are many other factors that enter into the latter, but we might want to remember that Don Jackson reported an increase in accuracy for 5 out of six substandard barrels, and my experience (although I would not call my barrel substandard) was similar, a slight increase in accuracy and a broader in tune condition. Jackie and Gene have given us a lot on the subject, and Dick Wright as well, all favorable.
It seems to me that regardless of arguments about how tuners work, that there is ample evidence that they do something that can be beneficial. It also seems to me that all of this discussion about terminology has become a waste of bandwidth that could be better used reporting and discussing actual results. Oh how I wish that I had a lathe (no place to put one). There are so many experiments left to do on this subject that might further refine what are already favorable results. Many thanks to those of you who have taken the time to report your results. I have enjoyed reading them and looking at the pictures. Carry on.
Of course one does not need to have a tuner to tune a CF rifle, or to do well in matches, as there are many other factors that enter into the latter, but we might want to remember that Don Jackson reported an increase in accuracy for 5 out of six substandard barrels, and my experience (although I would not call my barrel substandard) was similar, a slight increase in accuracy and a broader in tune condition. Jackie and Gene have given us a lot on the subject, and Dick Wright as well, all favorable.
It seems to me that regardless of arguments about how tuners work, that there is ample evidence that they do something that can be beneficial. It also seems to me that all of this discussion about terminology has become a waste of bandwidth that could be better used reporting and discussing actual results. Oh how I wish that I had a lathe (no place to put one). There are so many experiments left to do on this subject that might further refine what are already favorable results. Many thanks to those of you who have taken the time to report your results. I have enjoyed reading them and looking at the pictures. Carry on.
B
Bobby T.
Guest
Boyd, nicely put.
Bobby
Bobby
C
camjohnson
Guest
basic vibrations
I don't want to get too involved with this but I'd like to add a little background.
First: As Al said this is not steady state and most people are talking steady state.
Second: "If" we talk steady state then first we have to define what is a node. Typically a node is a zero on a 'displacement' curve...not a velocity curve. Therefore, a node is a point where the displacement is zero not the slope or velocity. So in your hypothetical sine wave, the zero crossing is the node. However, you will notice that the slope is the greatest. Assuming your barrel was pointing in the direction of the sine wave at the node...the barrel direction would be making a maximum in its change of direction (or slope/aiming point). This would not appear to be in the best interest of accuracy.
Third: vibration edge conditions are: 'free', 'simply supported', 'clamped', or somewhere in between. We can argue about the chamber end but the end of the barrel is pretty close to 'free'. Vibration of a 'free' edge condition does not result in a node at the 'free' edge. So don't expect a node at the end of the barrel (not that you would want one....see above coment). So don't expect to put a tuner at a node if you are putting it at the end of the barrel. And it wouldn't work too well at a node anyway. If this was not a node... when the sine wave is at a peak in displacement the velocity is minimum so the barrel is moving the slowest. That is why people tune by watching the groups and adjust either to a maximum or minimum....never at half way in between. They tune for a minimum velocity which is actually an 'anti-node' at maximum displacement. Think of a pendulum...at the end of each swing of the pendulum the weight slows for a short period as it changes direction. This is the point when the weight is moving the slowest and where we tune for. If we tuned for when the pendulum was straight up and down... then it would be a maximum velocity and very sensitive to slight changes in anything affecting the frequency of the pendulum. In the rifle situation that would mean it would be more difficult to have the barrel at the same point in the vibration with variations in powder, etc.
Fourth: both added mass and length affect the frequency of the vibration. Adding the tuner changes mass, adjusting it changes length. Both affect the frequency of the vibration.
Fifth: barrels are not completely symmetrical. People assume that all vibrations are just vertical. However the barrel may vibrate on any plane(and does)...and since the barrel isn't perfectly symmetrical the horizontal or off-axis vibrations may be at slightly different frequencies than the vertical vibration. Adjusting a tuner affects all vibrations but it is likely only one will adjusted to your minimum velocity/maximum amplitude. What Bill Calfee says regarding nodes doesn't make sense to me...even assuming steady state (which we know isn't true).
This isn't to say his tuners don't work....just that his explanation doesn't seem to make sense....to me.
Finally....let me reemphasize....this is for steady state vibrations and barrel vibrations are transient and not steady state. Varmint Al is correct.
I don't want to get too involved with this but I'd like to add a little background.
First: As Al said this is not steady state and most people are talking steady state.
Second: "If" we talk steady state then first we have to define what is a node. Typically a node is a zero on a 'displacement' curve...not a velocity curve. Therefore, a node is a point where the displacement is zero not the slope or velocity. So in your hypothetical sine wave, the zero crossing is the node. However, you will notice that the slope is the greatest. Assuming your barrel was pointing in the direction of the sine wave at the node...the barrel direction would be making a maximum in its change of direction (or slope/aiming point). This would not appear to be in the best interest of accuracy.
Third: vibration edge conditions are: 'free', 'simply supported', 'clamped', or somewhere in between. We can argue about the chamber end but the end of the barrel is pretty close to 'free'. Vibration of a 'free' edge condition does not result in a node at the 'free' edge. So don't expect a node at the end of the barrel (not that you would want one....see above coment). So don't expect to put a tuner at a node if you are putting it at the end of the barrel. And it wouldn't work too well at a node anyway. If this was not a node... when the sine wave is at a peak in displacement the velocity is minimum so the barrel is moving the slowest. That is why people tune by watching the groups and adjust either to a maximum or minimum....never at half way in between. They tune for a minimum velocity which is actually an 'anti-node' at maximum displacement. Think of a pendulum...at the end of each swing of the pendulum the weight slows for a short period as it changes direction. This is the point when the weight is moving the slowest and where we tune for. If we tuned for when the pendulum was straight up and down... then it would be a maximum velocity and very sensitive to slight changes in anything affecting the frequency of the pendulum. In the rifle situation that would mean it would be more difficult to have the barrel at the same point in the vibration with variations in powder, etc.
Fourth: both added mass and length affect the frequency of the vibration. Adding the tuner changes mass, adjusting it changes length. Both affect the frequency of the vibration.
Fifth: barrels are not completely symmetrical. People assume that all vibrations are just vertical. However the barrel may vibrate on any plane(and does)...and since the barrel isn't perfectly symmetrical the horizontal or off-axis vibrations may be at slightly different frequencies than the vertical vibration. Adjusting a tuner affects all vibrations but it is likely only one will adjusted to your minimum velocity/maximum amplitude. What Bill Calfee says regarding nodes doesn't make sense to me...even assuming steady state (which we know isn't true).
This isn't to say his tuners don't work....just that his explanation doesn't seem to make sense....to me.
Finally....let me reemphasize....this is for steady state vibrations and barrel vibrations are transient and not steady state. Varmint Al is correct.
C
camjohnson
Guest
addendum
For the purest. A node can occur in the middle of a vibrating object or at the edges (if the edge is simply supported or clamped). A node in the middle or at a simply supported edge will have zero displacement but not zero slope. A node at a clamped edge will have both zero displacement and zero slope. Sure... it would be nice to have a node at the end of the barrel if it had zero displacement and zero slope but a truely clamped edge condition is not possible at the muzzle end of the barrel.
For the purest. A node can occur in the middle of a vibrating object or at the edges (if the edge is simply supported or clamped). A node in the middle or at a simply supported edge will have zero displacement but not zero slope. A node at a clamped edge will have both zero displacement and zero slope. Sure... it would be nice to have a node at the end of the barrel if it had zero displacement and zero slope but a truely clamped edge condition is not possible at the muzzle end of the barrel.
camjohnson,
It's purist.
I don't know exactly what you're trying to say. (not because I'm incapable, but because it's muddled) I've got to take issue with some of your statements. This is the freakin' centerfire board, Calfee or not...
You state as FACT that "when the sine wave is at a peak in displacement the velocity is minimum so the barrel is moving the slowest. That is why people tune by watching the groups and adjust either to a maximum or minimum....never at half way in between. They tune for a minimum velocity which is actually an 'anti-node' at maximum displacement."
Sez WHO??? ---------WHERE did you get the idea that people are tuning for "minimum velocity"??? I for one think that the exact opposite is true, we tune for MAX velocity, this is where the compensation takes place........compensation out at the end of the swing (and coincidentally the point of lowest angular displacement or your term, slope) seems a liddle counterproductive, not?
and this, "So don't expect a node at the end of the barrel (not that you would want one....see above coment)."
A'gain, sez WHO???----------The POINT of a tuner is to move the node to the end.....
And this "People assume that all vibrations are just vertical. However the barrel may vibrate on any plane(and does)." .........
Sez WHO???----------And IF YOU'RE RIGHT and barrels just wabble about randomly then what is "vertical" and how is it "tuned for"?
And this whole "clamped edge" thing............just WHAT would your mythical "clamped edge effect" accomplish? WHY would it be "nice"? Is this a "stopped muzzle" thing that you "don't know how it works but it does, just not by stopping the muzzle"?
How do you think tuning works? What's the actual REASON that a tuned rifle will shoot smaller groups........because the muzzle is moving "slowly" and is "at the end of it's swing" and so the bullets go in the same hole??? HOW does this allow faster bullets to go down the same hole as the slower ones??
al
It's purist.
I don't know exactly what you're trying to say. (not because I'm incapable, but because it's muddled) I've got to take issue with some of your statements. This is the freakin' centerfire board, Calfee or not...
You state as FACT that "when the sine wave is at a peak in displacement the velocity is minimum so the barrel is moving the slowest. That is why people tune by watching the groups and adjust either to a maximum or minimum....never at half way in between. They tune for a minimum velocity which is actually an 'anti-node' at maximum displacement."
Sez WHO??? ---------WHERE did you get the idea that people are tuning for "minimum velocity"??? I for one think that the exact opposite is true, we tune for MAX velocity, this is where the compensation takes place........compensation out at the end of the swing (and coincidentally the point of lowest angular displacement or your term, slope) seems a liddle counterproductive, not?
and this, "So don't expect a node at the end of the barrel (not that you would want one....see above coment)."
A'gain, sez WHO???----------The POINT of a tuner is to move the node to the end.....
And this "People assume that all vibrations are just vertical. However the barrel may vibrate on any plane(and does)." .........
Sez WHO???----------And IF YOU'RE RIGHT and barrels just wabble about randomly then what is "vertical" and how is it "tuned for"?
And this whole "clamped edge" thing............just WHAT would your mythical "clamped edge effect" accomplish? WHY would it be "nice"? Is this a "stopped muzzle" thing that you "don't know how it works but it does, just not by stopping the muzzle"?
How do you think tuning works? What's the actual REASON that a tuned rifle will shoot smaller groups........because the muzzle is moving "slowly" and is "at the end of it's swing" and so the bullets go in the same hole??? HOW does this allow faster bullets to go down the same hole as the slower ones??
al
Boyd Allen
Active member
Al,
What you have brought to the table, for this discussion, is huge. Now, about that zero gravity thing, how do the results change if your use support in the usual places with 1G ?
What you have brought to the table, for this discussion, is huge. Now, about that zero gravity thing, how do the results change if your use support in the usual places with 1G ?
Varmin Al
Al
Did Esten move the node to the muzzle at any point in his testing regardless of the weight? many of us are not restricted by weight and would like to know if this is even possible.We hear from everybody wanting to scream the loudest but we never hear if this is even possible.Your thoughts would be much appreciated.
I also think everyone is using steady state conditions because it is easier to visualise what is going on.The sine wave example should really be explained better but we have limited space here.Imagine every point on the sine wave as the muzzle over time rather than the entire barrel in a big sideways "S".In that example 90 degrees and 270 degrees would be the muzzle at is slowest points.0,180 and 360 degrees would be the fastest points.
Lynn
Al
Did Esten move the node to the muzzle at any point in his testing regardless of the weight? many of us are not restricted by weight and would like to know if this is even possible.We hear from everybody wanting to scream the loudest but we never hear if this is even possible.Your thoughts would be much appreciated.
I also think everyone is using steady state conditions because it is easier to visualise what is going on.The sine wave example should really be explained better but we have limited space here.Imagine every point on the sine wave as the muzzle over time rather than the entire barrel in a big sideways "S".In that example 90 degrees and 270 degrees would be the muzzle at is slowest points.0,180 and 360 degrees would be the fastest points.
Lynn
K
Kathy
Guest
Friend Boyd Allen
Friend Boyd Allen:
Even though I started this thread, I almost feel like I'm buttin in....
I quote form you:
"Al,
"What you have brought to the table, for this discussion, is huge."
I totally agree, it's huge...........................I've neveer seen it stacked so high...
Your friend, Bill Calfee
Friend Boyd Allen:
Even though I started this thread, I almost feel like I'm buttin in....
I quote form you:
"Al,
"What you have brought to the table, for this discussion, is huge."
I totally agree, it's huge...........................I've neveer seen it stacked so high...
Your friend, Bill Calfee
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Boyd Allen
Active member
Al,
Sorry, I should have been clearer. What I meant to ask was how the vibration patterns in the whole rifle, as shown in your great animations are changed by gravity and the rifle being supported as it usually is, rest with sandbag in front, rear sandbag in rear. My thought is that the placement and physical characteristics of the supports play a role in determining how things shake before the bullet leaves.
Sorry, I should have been clearer. What I meant to ask was how the vibration patterns in the whole rifle, as shown in your great animations are changed by gravity and the rifle being supported as it usually is, rest with sandbag in front, rear sandbag in rear. My thought is that the placement and physical characteristics of the supports play a role in determining how things shake before the bullet leaves.
V
Vibe
Guest
The end of the swing IS the point of minimum velocity. In fact just before it changes direction the translation velocity is zero.
See the patent on the Browning Boss - they clearly state that their aim was to move an "Anti-node" to the muzzle to capitalize on the "end of swing" reduction in translation speed.
The largest of the motions is in the vertical, due to the removal of the gravity sag during firing, but there are other vectors, they are just usually of much smaller magnitude.
It's been done- Wasn't it Hatcher that poured a solid concrete pier around a barrels muzzle section in order to reduce the muzzle whip to zero - That would be an example of a clamped edge. It's a usefull example for the discussion of the physics involved - but of course the rifle thus fitted will not make weight.
Same way as with the node at the muzzle -the slower moving bullet leaves with more vertical velocity than the faster moving bullet does. With the muzzle node it's due to angle, with the muzzle anti node it's due to both muzzle speed and angle. Tuning is what allows you the control to select where in the barrel movement pattern you allow the bullet to exit. And it can be done in many ways, load modification, pressure curve manipulations (including seating depth), and changes to the barrel harmonics (the topic being discussed here.)