finding an "accuracy node".

[spclark]

... But I see vibration and barrel whip more then the wave theory... I see the pool as round and a barrel round, okay send a rock down the center of the pool and the vibrations (wave) go outward not up and down....

Ah but that's the part that gets tricky to fit to the pool vs. barrel analogy.

Pool's very wide & not deep at all while a barrel's just the opposite. Vibrations occur in all 4 dimensions simultaneously.

What you see as a wave is vibration in two dimensions - up/down as well as in/out - while time takes care of the third as the wave moves outward, only to have the vibrations reflected back once they encounter the pool sides, or an object in the water.

In a barrel the vibrations are moving in/out as well as forward/backwards while the barrel and action metal are reacting in a manner similar to the water in the pool but at a MUCH FASTER frequency, the difference owing to the nature of the different materials.

How do you know if your tuning to whip or wave?

They're both effects of vibration so it really doesn't matter.

Whip is mostly in two dimensions (up/down or side-to-side and time) while wave in this case might be in all four, one of which is causing what you see as whip: that particular dimension (say, up/down) has more freedom of movement where the effect is expressed to a degree you can actually see or feel.

Everything we do in building a rifle and loading components ought to be to make the system - rifle + ammunition - work in as consistent manner as possible. Tuners work to reduce or redirect the energy of vibrations, which will ALWAYS be present, so that the system performs most consistently under a particular set of conditions present.

Ray please keep contributing! Your posts are always worth reading and usually cause me to think about things a little differently. You've earned your two scoops for this thread.

 

[Raythemanroe]

I like this bit of information better and I guess it makes more sense to me. In reality whip and wave are all the same vibration from the shock wave or explosion going on..

I do have a thought, Would your bore being concentric with the outside diameter give better harmonics therefore maybe giving a bigger window fore a given node? Just a thought..


Ray

 

[jlow]

. Tuners work to reduce or redirect the energy of vibrations

In my simple minded thinking, I've always think of tuners as changing the length and weight of the barrel. The fact that you can screw the tuner in and out is like being able to changing the length of the barrel to the "right" length for your ammunition which still fits in the wave/flick idea.

 

[37Lincoln1]

Maybe a better analogy of thinking of waves as a rock in a pool but rather your barrel as a bell?

The pressure and velocity components of a standing wave between two hard boundaries

 

[spclark]

Maybe a better analogy of thinking of waves as a rock in a pool but rather your barrel as a bell?

Yep, bell or rifle barrel both 'ring like steel' when struck with a hammer blow, or cartridge being fired in the latter's case.

I chose the pool analogy because it's a common sight & easy to visualize. What metal crystals do when excited by energy (as vibration) is anything but, yet have a decided impact on the accuracy we seek.

 

[spclark]

Would your bore being concentric with the outside diameter give better harmonics therefore maybe giving a bigger window fore a given node? Just a thought..

And a good one! I think yes, absolutely!

Back into the pool (barrel)! If the rock (bullet in your bore) you toss lands off-center, the resulting waves (vibrations) get really confused as they bounce back and forth and encounter one another. The more centered up, the less confusion.

The more centered a rifle bore is to the outside circumference from breech to muzzle the more uniform the vibrations when fired... I suspect.

Or, using 37Lincoln1's bell analogy: a bell cast with varying wall thickness likely will ring flat from interference effects of vibrations passing thru different thickness of metal. Same with a rifle bore.

 

[spclark]

http://www.physicsclassroom.com/class/waves/Lesson-3/Interference-of-Waves

Scroll down to where lesson 3 begins, below the ads.

 

[Raythemanroe]

Would your bore being concentric with the outside diameter give better harmonics therefore maybe giving a bigger window fore a given node? Just a thought..

And a good one! I think yes, absolutely!

Back into the pool (barrel)! If the rock (bullet in your bore) you toss lands off-center, the resulting waves (vibrations) get really confused as they bounce back and forth and encounter one another. The more centered up, the less confusion.

The more centered a rifle bore is to the outside circumference from breech to muzzle the more uniform the vibrations when fired... I suspect.

Or, using 37Lincoln1's bell analogy: a bell cast with varying wall thickness likely will ring flat from interference effects of vibrations passing thru different thickness of metal. Same with a rifle bore.

I think most agree tuning helps with accuracy a bunch, so I have to believe having the bore concentric with the outside diameter would make a better tuning fork..JMO

Ray

 

[Raythemanroe]

http://www.physicsclassroom.com/class/waves/Lesson-3/Interference-of-Waves

Scroll down to where lesson 3 begins, below the ads.

You talking about destructive interference? I think we are on the same page here.


Ray

 

[jlow]

A good everyday example of this “destructive interference” is “noise cancelling” technology used in head phones and cars. The processor in these devices listens to the incoming noise and generates an opposite interfering wave which causes the two to cancel out. That obviously works.

 

[Raythemanroe]

A good everyday example of this “destructive interference” is “noise cancelling” technology used in head phones and cars. The processor in these devices listens to the incoming noise and generates an opposite interfering wave which causes the two to cancel out. That obviously works.

We shooters must call that a tuner


Ray

 

[jlow]

Well theoretically one could make something that generates those interference waves for a barrel. ;D

However, I don’t think our tuners work that way since they are passive and not active like the noise cancelling machines. I think the interference waves in our barrels are just the waves reflecting back when they reach the crown and/or chamber, when you got enough stuff going back and forth, some will bound to cancelling in nature. Where this happens is a function of barrel length thus the reason why the sweet spots/optimal barrel time have a number of nodes which is where the cancellation happens .

The tuners we use just allows you to adjust where they sit in the barrel so that they cancel out at the crown.

 

[spclark]

Where this happens is a function of barrel length...

And seating depth and powder charge and maybe neck tension and neck clearance (and sometimes action screw torque) and a couple more factors all affecting the harmonics at the muzzle end when the bullet's passing thru the crown; remember this event occurs over time, during which everything is still moving pretty fast!

The tuners we use just allows you to adjust where they sit in the barrel so that they cancel out at the crown.

Agreed, when they're being used. I've seen various devices intended for a similar purpose that are to be fitted to a barrel then moved back / forth or weighted / lightened. All provide another means to get those harmonics to work in our favor, not against us.

Destructive interference may play a roll somewhere but to what degree I haven't a clue. By adding that link to our discussion I wanted to introduce some explanation of wave theory in general. We're talking vibrations here & how to get them to work in our favor.

 

[Raythemanroe]

My post of destructive interference was related to not throwing the stone in the center of the pool... Tuners I would assume help align vibration to your benefit, again assuming your using it properly..


Ray

 

[jlow]

And seating depth and powder charge and maybe neck tension and neck clearance (and sometimes action screw torque) and a couple more factors all affecting the harmonics at the muzzle end when the bullet's passing thru the crown; remember this event occurs over time, during which everything is still moving pretty fast!

Seems like when you change those things, are you not really affecting barrel harmonics but tuning your rounds so that you can get the bullet consistently out pass the crown at a specific time?

 

[Raythemanroe]

I think of it as a window that is the most consistent time after time...Who knows, maybe both camps are right..It could be a time that wave and whip interfere the least.. <<<< That is my PC answer




Ray

 

[spclark]

Seems like when you change those things, are you not really affecting barrel harmonics but tuning your rounds so that you can get the bullet consistently out pass the crown at a specific time?

To my thinking it's a 'handshake': a change to each single factor has an effect on one or more performance parameters. Why tuning can be such a challenge.

The task is to work thru the variables so that the net effect of all of your practices gets your rounds out through a muzzle that's in a repeatably 'calm' (for lack of a better word) condition. That's the grail.

 

[lpreddick]

instead of a round pool and stone use a rectangular "pool" with water equally as deep as wide, 28" long and 3" wide and deep. drop the stone at one end and watch the waves. the forward wave will go to the end of the pool and return several times and continue to do so until dampened by the resistence of the water. are not our barrels doing something like this?

 

[CatShooter]

instead of a round pool and stone use a rectangular "pool" with water equally as deep as wide, 28" long and 3" wide and deep. drop the stone at one end and watch the waves. the forward wave will go to the end of the pool and return several times and continue to do so until dampened by the resistence of the water. are not our barrels doing something like this?

No...

 

[Alex Wheeler]

Are there any actual facts known about barrel vibration/harmonics or is it all theory?