barrell oscillation's effect on accuracy

[razorbritches]

What affect would barrel oscillation have on smooth bore accuracy, what I'm trying to say is if the barrel was tuned to a particular wave length or, say musical note maybe. Would a whole note, a sharp or a flat affect accuracy and, to what degree? Also what affect would a straight or a tapered barrel have on the same? Sorta like tuning a wind chime to a particular note. Is length something that can be tuned to better affect and how

 

[jdkerstetter]

Wow! That's probably was outside the usual content of this forum and likely why it hasn't generated more response.

I don't have an answer for you other than to say any tuning of the barrel would be mute after you attach it to the gun.

How would one test this in the first place? Accuarcy that is? Any method of holding the barrel to test it would interfere with the harmonics. Any "tuning" would have to be done after mounting.

As to your second question, the one on heavy versus tapered, one can surmise from all past evidence that a heavy, stiff walled barrel will have better repeatable accuracy than a light, thin one.

Hope that helps. Enjoy, J.D.

 

[jamesthomas]

I personally think that a muzzleloader does not create enough fps to have any affect on barrel harmonics. So just take it out an shoot it. Blackpowder shooting ain't an should not be rocket science.

 

[Dane]

razor,

You've got entirely too much time on your hands. Get a hobby, like shooting black powder rifles. (minus the philosophy) In other words...... just shoot the damn thing.

 

[necchi]

What affect would barrel oscillation have on smooth bore accuracy

Damn little,
While Oscillation and the other Harmonics play a big role with high pressure/high velocity CF when working a load, the study applies only marginally to Traditonal BP Ml's.
There simply isn't enough velocity being created.
A Barrel Oscillation created by detonation of a BP charge even with a variable of +/-2-3 grains will occur as with CF several times before a shot charge or solid projectile can leave the barrel.

Working within the charge velocity variables of subsonic through up to say 18-1900 fps simply isn't enough to matter especially with a smoothy.

 

[M. De Land]

I don't think accuracy with smooth bore shooting ,which I must say from the get go I know little experientially about, has as much to do with barrel harmonics as it does with a non spinning ball passing through the transonic barrier which is more disruptive to most any projectile than when above or below. That range of velocity is 900 fps to roughly 1300 fps.
I think this is the biggest reason accuracy falls off dramatically past about 65 yards, or so. Kind of reminds me of how a good knuckle ball works as it approaches the plate when it begins to jink around.
I do know that rifled muskets can be accuracy improved by barrel shimming at the bands which definitely effects barrel harmonics.
I think you ask a very good question because the physics of round, non-spun ball shooting is quite different from bullet exterior ballistics. Mike D.

 

[Rod Lassey]

Not a muzzleloader, but the US Army did extensive barrel harmonics testing with the 1873 Springfield in 45-70. While a centerfire cartridge rifle, it is somewhat comparable to muzzleloaders in that the velocities and pressures are similar.

Just to let you know guys 'back then' were thinking of this very question, too.

Rod

 

[Billnpatti]

Barrel harmonics is much more applicable to the CF guns than to muzzleloading guns. Muzzleloading guns do not generate the pressures that a CF will and the barrel wall is much thicker and consequently more rigid and less subject to harmonic vibrations than a CF. No doubt there are some very minor harmonics but not enough to seriously effect accuracy. A muzzleloader has many more variables that have a much greater impact on accuracy than barrel harmonics ever will.

BTW, please feel free to ask any questions you may have. Don't be discouraged by the few who berate you for any "philosophical" questions you may have. That is not the way we roll on this forum. If you want to know anything, there is no such thing as a stupid question. We are all (with a few exceptions) more than willing to share what we know. Just ask. :thumbsup:

 

[FishDFly]

Okay, AM, FM, FM Stereo, 5 string or 6 string with or without Amp., need to narrow the field a bit.

This has to be the best troll ever.

Let the testing begin with statistical data to prove harmonics.

Can we have chrony. readings comparing the tuning to 2F and 3F, cleaning and not cleaning between shots, with weighed powder charges and weighed balls to verify the harmonics with different loads and not weighted also.

Now how about temperature, and relative humidity changes on harmonics.

I thought this place was about shooting, is it not?

 

[Robby]

Razor, I come from the school of "every thing affects everything". Two questions, to what degree?, and is it a positive or negative?. Everything has a frequency, or as I call it a bend moment. This is why a barrel will have different measures of powder to give it optimum accuracy. As you up the ante the barrel will fall in and out of favor with your load, but there are several loads that will give you optimum accuracy. You just have to find them and that is part of the fun of it.
Robby

 

[jdkerstetter]

...and the barrel wall is much thicker and consequently more rigid and less subject to harmonic vibrations than a CF.

Um, Bill, perhaps you're not shooting balls from some of the octagon/round barrels out there....some are much thinner than their CF brethern. Furthermore, when you compair barrel cross section on most centerfires to bore diameter the ratio ends up equal to or thinner than many octagon barreled ML rifles.

Not arguing for or against harmonics, just debunking this part of the equation. Enjoy, J.D.

 

[BrownBear]

...smooth bore....

What would cause the oscillation?

 

[Billnpatti]

Hmmmmm.......well......er......uh.....yeah, what you said. But.....uh.....are ya sure? I mean really, really fur sure? That is to say if the CF barrels are, as you say, thinner than the octagon barrels of a muzzleloader and operate under higher pressure wouldn't that mean that they would be more prone to greater harmonics? :hmm: Just sayin'. :blah: :haha:

 

[jdkerstetter]

Bill, Perhaps I typed part of my post backwards. Didn't think I did but there it is.

....most centerfires to bore diameter the ratio ends up equal to or thinner (should read thicker) than many octagon barreled ML rifles.

Above you said ML barrels are thicker and stiffer than CF barrels. I made the opposite observation.

Many ML barrels have a thinner wall thickness to bore ratio than CF guns.....even the full octgon barrels.

And again, I ended my previous post saying I was not making a case for one side or the other on harmonics.....just debunking your previous statement about barrel thickness and stiffness. :wink:

Enjoy, J.D.

 

[necchi]

Oscillation of a harmonic node in any of several barrel conditions while a charge is fired is just a term used to describe a repeated movement.
It doesn't define Torsion, Bending, Rotation or Extension,,,

Like an Oscillating Fan, the "blades rotate" while the fan oscillates (moves back an forth)

 

[kaintuck]

not much.....
get a swed M96 ... 6.5X55.....
I had a 1913 model....handloads would pop gallon milk jugs at 550YD all day long...with the iron sights....

I like flinters....just because.....
well, i also like Paris Hilton~~~ :youcrazy:
but then...........I am a pirate at heart....
:stir: :youcrazy: :rotf:

 

[Billnpatti]

Is that your final answer? :rotf: It's fun to poke a buddy in the ribs sometimes. :wink:

 

[M. De Land]

Actually barrel oscillation is not linear in a rifle but rather helixial and oval in cross section because of the effects of gravity on the barrels length. I suspect the same is true in ball guns as well but not as extreme.
As I explained in another post, that is the reason taper or choke boring increases accuracy. It tensions the barrel by increasing resistance on the projectile and dampens the tendency to oscillate. Heavy rigid barrels, free from internal stresses and with straight bores resist the tendency to oscillate as well.
Some of the very early,super accurate slug guns had iron barrels so soft you could turn a curl with a pocket knife and were usually very heavy in cross section. Both qualities tend to negate barrel movement and increase accuracy. Mike D.

 

[jdkerstetter]

We're good Bill. Like anybody else, sometimes what my fingers type isn't exactly what I'm thinking. I can walk and chew gun at the same time though. :haha: Ejoy, J.D.

 

[Rifleman1776]

Actually barrel oscillation is not linear in a rifle but rather helixial and oval in cross section because of the effects of gravity on the barrels length. I suspect the same is true in ball guns as well but not as extreme.
As I explained in another post, that is the reason taper or choke boring increases accuracy. It tensions the barrel by increasing resistance on the projectile and dampens the tendency to oscillate. Heavy rigid barrels, free from internal stresses and with straight bores resist the tendency to oscillate as well.
Some of the very early,super accurate slug guns had iron barrels so soft you could turn a curl with a pocket knife and were usually very heavy in cross section. Both qualities tend to negate barrel movement and increase accuracy. Mike D.

I once made similar comments here and included swamping as one way of dampening harmonic vibrations. I made those comments based on an article in a Muzzle Blasts from many years ago. I got my fingers slapped mightly for saying those things. Everyone wanted a "link" to prove what I said. The article was decades before "links" were avaialble. I would love to still have that issue today. Oh, well.