Friends ThaiBoxer and MikeP57, Calfee

[Vibe]

Everyone should know about google by now.
http://www.google.com/search?hl=en&safe=off&q=parallel+node+precision+shooting&meta=

Thanks Shorty.
http://www.ozfclass.com/articles/1/psm_2005_03.html
But since figure 6a is indeed more correct than figure 6B due to the lack of an additional source of bending moment, and not as incorrect as Bill assumes. His tuners work for the same reason in this case as they did when the bullets exit during the "partial cycle" - exiting while at the reversal point of the vibration.
In fact the form of the motion - vibration if you will - is closer to a combination of Figure 2 and Figure 3. But then Varmint Als FEA Model has already accurately showed that behaviour.
http://www.varmintal.com/atune.htm

 

[Jetmugg]

Materials science.

From a pure materials science perspective, Vibe's assertions are correct. Rifle barrels are made from elastic materials which behave in 100% predictable ways. If there is a true wave present in the barrel, there will only be infinitessimally small sections of the barrel which could be defined as "parallel" to a theorhetical straight line from the receiver to the target. There will not be "straight" sections of barrel and "wavy" sections of barrel. The computer modeling of barrel movement is correct.

Bill Calfee is a well known and respected gunsmith, but the type of "backwoods engineering" logic described in the Precision Shooting article does not stand up to a scientific analysis of the issue described.

My 2 cents,

SteveM.

 

[Jetmugg]

The links provided by Vibe

"You guys seem to be saying a barrel is a sine wave with a perfection reflection coefficient at its muzzle regardless of length or zero reflected wave."

Who said that? The first link provided by Vibe (Threerivers model) describes a 4th order equation with respect to distance, and second order with respect to time. It is not described as a sine wave (triginometric function).

If your bullet starts out at zero fps then ramps up to 1100 fps are you saying there is only one wave set-up inside the barrel and who is your source for that assumption?


I would recommend checking the computer model for the answer to that question.

Is it possible for the barrel to have multiple waves both incident and reflected ahead of the bullet and would they be additive in property or would they cancel again your sources would be appreciated

Yes. The interaction of incident and reflected waves can be modeled, and will depend on a wide range of variables. Remember that rifle barrels are elastic, and have measurable mechanical and physical properties.

A good computer model can be used to predict the behavior of just about any product made from an engineering material. The more sophisticated the model (allowing the manipulation of many variables), the better the results will be. Ultimately, a better understanding of the way a rifle barrel behaves will result in better accuracy.

SteveM

 

[Jetmugg]

Oops.

Lynn:
I probably wasn't clear enough when I mentioned the first link that Vibe posted on this subject. It was actually in another thread. Here is the link.

http://www.vni.com/successes/threerivers.php

The article by Calfee is a bit too simplified. I think that when Vibe was mentioning the differences between figures 6A and 6B in Calfee's article, he was only saying that 6A is more accurate than 6B at the location of the inflection point. (note- I'm not qualified to speak for Vibe, but that's the way I understood it anyway).

SteveM.

 

[Vibe]

Steve hopefully Vibe will read this post and respond.In the link you provided above I see no differences from what Mr Calfee and countless others are now saying.The 6A and 6B diagrams from Bill Calfee seem to be in total agreement with the 5A and 5B diagrams in Vibes link? 5A is sans tuner and 5B is with it and it shows a lengthy "dead zone""stopped muzzle" or whatever todays fashionable term is.
In the link written by a software company not associated with any form of shooting sports other than software they refer to a longer period of time were the baseline bore axis is perpindicular to the exit time bore axis.Isn't that exactly what Mr Calfee has been saying for years now?

It seems to myself we would rather argue over the verbage than to actually accomplish anything of substantial value.I refer you back to the centerfire forum were the term "Stopped Muzzle" was hottly debated for several thousand views.Nothing on planet earth has ever been "Stopped" yet we would rather argue than except the intent of the poster.It boggles the mind.
Lynn

But you see Lynn - the Three Rivers project involved some extensive recutting of the barrel profile, and thus modifying the cantelever behaviour, in addition to adding multiple masses of specific shapes and weights to accomplish this combination of wave shapes. Researching the patents applied for by the authors of that study reveals this. It can also be seen in the design of the Ruger Target Mini-14 tuner. It's a far cry from simply strapping on a specific mass in front of the muzzle. And yes the verbage used is extremely important and must be as accurate as the end result of the device.

However you should also note that I have never stated that the device itself was not effective - only that the description of why was in error, as it was contrary to the behaviour of the shapes under discussion.