Video Illustration of tuning loads to barrel harmonics

[Ledd Slinger]

My Proof Carbon barrel was just finished the other day but I'm still waiting on the stock and action. This will be my first Proof barrel. In anticipation I was watching some videos on Proof barrels and although the video below is talking about AR barrels and my rifle will be a bolt action, the video has some great graphics and narrative illustrating and explaining barrel harmonics and tuning loads to the unique frequency wave of each individual barrel.

For anyone interested in how barrel harmonics play into load tuning, this video uses great video animation graphics to give you a little insight on how it works. This is why you hear shooters talking about "accuracy nodes" at certain speed levels. The accuracy nodes are when the bullets are exiting the muzzle in tune with the barrel harminic frequency wave. You can also see why it is important for a riflesmith to index a barrel at 12 or 6 o'clock. Pretty cool little video anyhow.

Also a good video explaining how carbon fiber barrels are made and how they work.

 

[SGK]

Regarding carbon 'wrapped' barrels, the boys in New Zealand are out front with respect to carbon technology due to the high performance yacht racing industry there. Check out Hardy Rifle Engineering. https://www.hardyrifle.co.nz/copy-of-stainless-barrels

 

[boltfluter]

Let's,

Great video! Thanks for sharing. Like you, I just received my first Proof carbon fiber barrel. Should be a fun new build.

Paul

 

[Ledd Slinger]

Regarding carbon 'wrapped' barrels, the boys in New Zealand are out front with respect to carbon technology due to the high performance yacht racing industry there. Check out Hardy Rifle Engineering. https://www.hardyrifle.co.nz/copy-of-stainless-barrels

Holy cow! I think I need to draw the line when the cost of a barrel is as much or more than the cost of a custom action. I'm sure they shoot good tho

 

[Raythemanroe]

I quit watching after he compares accuracy with a barely known barrel manufacturer and a carbon wrap using a AR with one type of factory ammo. Wish I could have hung on until it got to the tuning..

Ray

 

[Ledd Slinger]

I quit watching after he compares accuracy with a barely known barrel manufacturer and a carbon wrap using a AR with one type of factory ammo. Wish I could have hung on until it got to the tuning..

Ray

Yeah that part has nothing to do with why I posted the video. All pointless to me as well. The entire video is only 6 minutes long so you couldnt have tried very hard. Lol If you decide to try again, theres a cool feature on videos these days that allows you to 'fast forward'

The part I am talking about starts at about the 2:00 minute mark

 

[SGK]

Holy cow! I think I need to draw the line when the cost of a barrel is as much or more than the cost of a custom action. I'm sure they shoot good tho

NZ dollars on their website. Multiply by 0.68.

 

[Bart B.]

While carbon fiber is several times stronger than steel, it's only about twice as stiff. Wrapping a .7" dia barrel with a few bonded layers of carbon fiber will make it stiffer. How much is critical for a valid comparison with an all steel one of the same profile.

Too bad that video didn't show the actual muzzle axis vertical swing that both barrel types have for a valid comparison. The finite element software mechanical engineering folks use would best show differences. That video shows several barrel vibration cycles at different places during barrel time. There's only one in reality that's important, it's that of the muzzle when the bullet leaves at about one cycle during barrel time.

If you understand how barrel tuners work, you'll understand.

 

[SGK]

While carbon fiber is several times stronger than steel, it's only about twice as stiff.

Depends on the process. Can be 8-10x stronger and up to 3x, 4x or more stiffer.

 

[Delfuego]

I think he has it pretty figured out. He said he will be shooting "PRS" soon too. Check out his sweet rig...



Man I wish my bipod/monopod was that ninja

 

[rckendall]

Depends on the process. Can be 8-10x stronger and up to 3x, 4x or more stiffer.

Aren't all the claims of superior strength to steel based on weight, not size? I'm just asking, but that is the way I remember. I hope someone can verify this.

Richard

 

[Mark M.]

Thx Great info

 

[Ledd Slinger]

I know the video is not a complete analysis and detailed description on barrel harmonics and load tuning. And I know many of you understand the subject on a much higher level than the video portrays. I shared the video because I thought it provided a good quick synopsis on the subject. There are other articles that go into a lot more detail, I just liked the video for the animations and thought it might help new shooters gain some insight on how it works.

I think the best key point in the entire video is when he mentions that EVERY barrel has it's own 'unique' harmonic frequency. This is VERY true. Rigidity isn't necessarily required to make a barrel shoot accurately, but it may make it easier to tune. A light whippy barrel can still shoot very well if a person is experienced with advanced load tuning techniques. It just may not offer as many load options to select from and the tuning windows will probably be smaller.

 

[Bart B.]

Depends on the process. Can be 8-10x stronger and up to 3x, 4x or more stiffer.

That could well be.

Promotional and advertising claims oft times are not reality. Like the video showing a bullet from the carbon fiber wrapped barrel leaving on the muzzle axis down swing. Worst time as their velocity spread won't be compensated for. Bullets need to leave on barrel's muzzle axis up swing.

 

[Bart B.]

I think the best key point in the entire video is when he mentions that EVERY barrel has it's own 'unique' harmonic frequency. This is VERY true.

Well, almost. All barrels with the same metal, profile, bore and chamber will have the same resonant and several (8?) harmonic frequencies. A few ten-thousandths inch spread across all barrel dimensions doesn't matter any significant amount.

 

[PatMiles]

That could well be.

Promotional and advertising claims oft times are not reality.

Reality? We don't need no stinking reality!

 

[Ledd Slinger]

Well, almost. All barrels with the same metal, profile, bore and chamber will have the same resonant and several (8?) harmonic frequencies. A few ten-thousandths inch spread across all barrel dimensions doesn't matter.

Tell yourself whatever you want. If only it was that easy wouldn't that be great!

 

[jsthntn247]

On this same subject, recently had a 100 yard test that looked like this. I could clearly see the barrel moving up and down in the groups. Which node would you go with based on group location (barrel harmonics) between 3 and 4 or between 7 and 8?

 

[PatMiles]

View attachment 1087169 On this same subject, recently had a 100 yard test that looked like this. I could clearly see the barrel moving up and down in the groups. Which node would you go with based on group location (barrel harmonics) between 3 and 4 or between 7 and 8?

With just targets to look at, 7/8 appear to be the winner.
Loads, velocities?

 

[Ledd Slinger]

View attachment 1087169 On this same subject, recently had a 100 yard test that looked like this. I could clearly see the barrel moving up and down in the groups. Which node would you go with based on group location (barrel harmonics) between 3 and 4 or between 7 and 8?

Can you load faster than group 8 or is that max pressure? If it holds together with same accuracy and POI at higher speeds than group 8 then you are getting into a nice node.