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Posted: 10/11/2005 7:10:45 PM EDT
How does barrel fluting make a barrel more rigid? How does removing material from a metal bar somehow make it stronger? If this is true, why don't they flute industrial metal bars or pipes used for construction, since it would make them stronger? Inquiring minds want to know!
Link Posted: 10/11/2005 7:13:04 PM EDT
[Last Edit: 10/11/2005 7:14:44 PM EDT by captainpooby]
It increases rigidity by weight.
You can make a barrel of a larger diameter weigh less and be more rigid than a barrel of the same weight but skinnier.
Link Posted: 10/11/2005 7:16:31 PM EDT
Fluting doesn't make anything "stronger"...what it does is make something that used to weigh, say, 5lb, weigh 3lb and be just as structually rigid.

If you've ever raced RC cars, an old RC10 trick was to drill holes in a certain pattern in the chassis. It would maintain it's structural strength while weighing less.

Same principal.

It would also give the barrel more surface area, allowing it to dissapate heat better/faster.



Link Posted: 10/11/2005 7:20:35 PM EDT
I have often heard that a fluted barrel will be more accurate than a non-fluted barrel because it is MORE rigid than the other. I thought it had more to do with the fact that the fluted barrel has more surface area, so more area to dissipate heat, thus resulting in greater accuracy. Which is right?
Link Posted: 10/11/2005 7:26:07 PM EDT
It's kind of like the difference between angle iron and the same amount of flat stock of equal lenght.
Link Posted: 10/11/2005 7:31:27 PM EDT

Originally Posted By FortyFiveAutomatic:
I have often heard that a fluted barrel will be more accurate than a non-fluted barrel because it is MORE rigid than the other. I thought it had more to do with the fact that the fluted barrel has more surface area, so more area to dissipate heat, thus resulting in greater accuracy. Which is right?



It disappates heat quicker, but how can you make it MORE rigid? Hang a superstructure on it?

More rigid, no. Just as rigid as an unfluted barrel, yes.

If you take a bull barrel, and a fluted bull barrel, and measure rigidity by any manner possible..they will be equal. Accuracy will be the same. The fluted barrel will heat up quicker but over time will last longer as the heat dissappates quicker (shoot 300 rounds through a bull barrel...it gets hot and stays hot for a while...the fluted will cool down quicker)

If someone insists a fluted barrel is more rigid than it's unfluted cousin, ask for mathmatical proof
Link Posted: 10/11/2005 7:31:54 PM EDT

Originally Posted By FortyFiveAutomatic:
I have often heard that a fluted barrel will be more accurate than a non-fluted barrel because it is MORE rigid than the other. I thought it had more to do with the fact that the fluted barrel has more surface area, so more area to dissipate heat, thus resulting in greater accuracy. Which is right?




It has to do with the crystalline structure of the metal. The flutes add a flat pane of crystals that do not want to bend across the long axis, where the unfluted barrel can bend across the same area because the crystals within the metal will still crack across the short axis (we see this as a bend).

Clear as mud?
Link Posted: 10/11/2005 7:35:49 PM EDT

Originally Posted By Jame_Retief:

Originally Posted By FortyFiveAutomatic:
I have often heard that a fluted barrel will be more accurate than a non-fluted barrel because it is MORE rigid than the other. I thought it had more to do with the fact that the fluted barrel has more surface area, so more area to dissipate heat, thus resulting in greater accuracy. Which is right?




It has to do with the crystalline structure of the metal. The flutes add a flat pane of crystals that do not want to bend across the long axis, where the unfluted barrel can bend across the same area because the crystals within the metal will still crack across the short axis (we see this as a bend).

Clear as mud?

Is this where we reverse the polarity couplings on the dilithium crystals in the matter/antimatter reactor core?
Link Posted: 10/11/2005 7:35:57 PM EDT
[Last Edit: 10/11/2005 7:37:31 PM EDT by MillerSHO]
Too be honest I've never heard this claim before.

To say it's MORE rigid then the same barrel unfluted is impossible.
To say it would just as structually rigid as the same barrel unfluted might be a bit of a stretch also.

As a fluted barreled AR owner I would say it does dissapate heat faster but since it does have less metal overall it heats up quicker I notice.

It's my understand that a fluted barrel has more whip then the same barrel unfluted that is why you never see fluted barrels on true pinpoint accuracy firearms.

When it comes down to weighing the pro's and con's, looks would be the deciding factor.
Link Posted: 10/11/2005 7:37:02 PM EDT
The question is "more rigid compared to WHAT?"

Suppose you start out with a 1" diameter barrel and cut fluting grooves into it. It will be less rigid than the original 1" diameter barrel--you don't make things stronger by taking away material.

Now compare the fluted barrel you just made to a straight barrel of the same weight. The straight barrel has a smaller diameter. It is also typically less rigid than the fluted barrel.

This has to do with what engineers call the "moment of inertia". Imagine trying to bend a yardstick. First you bend it along the flat side. The yardstick bends easily. Now try to bend it along the narrow side. It doesn't bend well at all, because there's more material farther away from the centerline. The same principle holds for the fluted barrel. It's more useful to have material further from the centerlilne than it is to have it close to the centerline. That's why I-Beams are shaped the way they are, with a narrow web and big flanges.

Also, the fluted barrel has more surface area. This helps cool the barrel faster--it's shaped like a mini heat exchanger.
Link Posted: 10/11/2005 7:38:03 PM EDT
[Last Edit: 10/11/2005 7:39:38 PM EDT by FortyFiveAutomatic]

Originally Posted By MillerSHO:

To say it's MORE rigid then the same barrel unfluted is impossible.
To say it would just as structually rigid as the same barrel unfluted might be a bit of a stretch also.




See this is the contention I am under. I wonder if someone can prove/disprove this mathematically, or very very convincingly qualitatively. So far I buy mcgredo's argument.
Link Posted: 10/11/2005 7:42:29 PM EDT

Originally Posted By FortyFiveAutomatic:
I wonder if someone can prove/disprove this mathematically, or very very convincingly qualitatively. So far I buy mcgredo's argument.



Don't make me go Statics on your ass.

www.efunda.com/formulae/solid_mechanics/beams/theory.cfm
Link Posted: 10/11/2005 7:42:39 PM EDT
[Last Edit: 10/11/2005 7:46:16 PM EDT by Cape_hunter]
All you will ever need to know about fluting. More then most will understand however

Look HERE & HERE

Read up before you open your piehole folks!
CH
Link Posted: 10/11/2005 7:45:53 PM EDT
Take my opinion for what it's worth but what I said in the previous post is what I learned when I was looking into fluting.

In the end I would have been fine with a standard HBAR.

It's kinda like my gas BBQ, I find out after the fact that I should have saved the dough and got the black model cause it works alittle better at trappin heat then SS.

Link Posted: 10/11/2005 7:46:25 PM EDT

Originally Posted By MillerSHO:
Too be honest I've never heard this claim before.

To say it's MORE rigid then the same barrel unfluted is impossible.

Correct

To say it would just as structually rigid as the same barrel unfluted might be a bit of a stretch also.
Also correct.

As a fluted barreled AR owner I would say it does dissapate heat faster but since it does have less metal overall it heats up quicker I notice.
ALSO correct!

It's my understand(ing) that a fluted barrel has more whip then the same barrel unfluted that is why you never see fluted barrels on true pinpoint accuracy firearms.
Not quite true. Yes, a fluted barrel is not quite as stiff as an unfluted barrel of the same overall diameter, but on true "pinpoint accuracy firearms" weight is not generally a concern, so fluting is seen as a disadvantage rather than an advantage. You can still build tremendously accurate guns with fluted barrels. Much more accurate and consistent than a rifle with a pencil-thin "hunting" barrel.

When it comes down to weighing the pro's and con's, looks would be the deciding factor.
"Weighing" being the operative word here.
Link Posted: 10/11/2005 7:46:50 PM EDT

Originally Posted By mcgredo:
The question is "more rigid compared to WHAT?"

Suppose you start out with a 1" diameter barrel and cut fluting grooves into it. It will be less rigid than the original 1" diameter barrel--you don't make things stronger by taking away material.

Now compare the fluted barrel you just made to a straight barrel of the same weight. The straight barrel has a smaller diameter. It is also typically less rigid than the fluted barrel.

This has to do with what engineers call the "moment of inertia". Imagine trying to bend a yardstick. First you bend it along the flat side. The yardstick bends easily. Now try to bend it along the narrow side. It doesn't bend well at all, because there's more material farther away from the centerline. The same principle holds for the fluted barrel. It's more useful to have material further from the centerlilne than it is to have it close to the centerline. That's why I-Beams are shaped the way they are, with a narrow web and big flanges.

Also, the fluted barrel has more surface area. This helps cool the barrel faster--it's shaped like a mini heat exchanger.



Everything you said is correct except "moment of inertia." Moment of inertia is an object's resistance to rotation, and is increased when mass is concentrated away from the center of gravity of an object. For example... Hold a 10-lb barbell in each hand, at arm's length, and try to spin around. You will accelerate slowly. Draw them against your chest, you accelerate easily, because while the mass is unchanged, the moment of intertia has been greatly reduced.

Link Posted: 10/11/2005 7:51:27 PM EDT
Whoops. That should be "radius of gyration."

It's been a while.

www.efunda.com/math/areas/RadiusOfGyrationDef.cfm
Link Posted: 10/11/2005 7:52:49 PM EDT
Link Posted: 10/11/2005 7:53:12 PM EDT


Link Posted: 10/11/2005 7:54:09 PM EDT

Originally Posted By Cape_hunter:
All you will ever need to know about fluting. More then most will understand however

Look HERE & HERE

Read up before you open your piehole folks!
CH



Way over my head, but I know subliminal gun porn when I see it!



Link Posted: 10/11/2005 7:56:42 PM EDT
[Last Edit: 10/11/2005 8:00:12 PM EDT by FortyFiveAutomatic]

Originally Posted By Tweak:
more rigid than an identical barrel of the same weight

think about it



Same weight implies that a solid barrel will have less diameter than the fluted, hence it will be less stiff. Is that correct?

As opposed to being more rigid than a solid barrel of the same diameter, which is, as I understand it, impossible?

SO IN OTHER WORDS, I should keep my solid barreled precision rifle as-is, considering weight is not a concern. Right?
Link Posted: 10/11/2005 7:59:36 PM EDT

Originally Posted By captainpooby:
www.varmintal.com/mbb1.gif




Beat me by a few seconds, but at least we're on the same wave length.

Link Posted: 10/11/2005 8:09:00 PM EDT
After seeing the pictures of the fluted and blown up savage and 50 cal, theres no way Im putting a fluted barrel on.
Link Posted: 10/11/2005 8:11:43 PM EDT
Why do people think of themselves as experts on physics? When they aint?


Two barrels OF EQUAL WEIGHT,

the fluted barrel is more rigid.


Two barrels of EQUAL DIAMETER,

the fluted barrel is less rigid.


This concept would be very very very very easy to show mathematically. It would be a freshman level mechanics of solids problem.


Moment of inertia is the value used in the elastic formulas to calculate deflection. The moment of inertia is also used for rotational dynamics problems.

Radius of gyration is not needed.


NO SHIT
Link Posted: 10/11/2005 8:14:13 PM EDT

Originally Posted By FortyFiveAutomatic:

Originally Posted By Tweak:
more rigid than an identical barrel of the same weight

think about it



Same weight implies that a solid barrel will have less diameter than the fluted, hence it will be less stiff. Is that correct?

As opposed to being more rigid than a solid barrel of the same diameter, which is, as I understand it, impossible?

SO IN OTHER WORDS, I should keep my solid barreled precision rifle as-is, considering weight is not a concern. Right?




That's it exactly.

Personally I think fluting is nothing more than a gimmick. Technically it will work but who cares?
Link Posted: 10/11/2005 8:16:30 PM EDT
ARFCOM hive mind ROCKS.

We should compile an ARFCOMpedia
Link Posted: 10/11/2005 8:44:10 PM EDT
[Last Edit: 10/11/2005 8:45:16 PM EDT by Max_Mike]

Originally Posted By red65:
Why do people think of themselves as experts on physics? When they aint?


Two barrels OF EQUAL WEIGHT,

the fluted barrel is more rigid.



That ain't correct

It depends entirelly on the lenght and diameter of the 2 barrels. With barrels of EQUAL DIAMETER AND EQUAL WEIGHT the fluted barrel is less rigid because it is longer.
Link Posted: 10/12/2005 1:13:07 PM EDT
Link Posted: 10/12/2005 1:18:09 PM EDT
I read like the first five replies and all I have to say is:

AGNTSA
Link Posted: 10/12/2005 2:54:04 PM EDT
I don't even know why people cared to bring "the same weight" into the debate.

When you flute a barrel you compare it to the same barrel that is unfluted.

You don't say, O this gov profile 16" A2 barrel has the same structure as my fluted 20"HBAR.

You compare it the similar barrel unfluted and leave it at that.

Geez guys.

derr derr
Link Posted: 10/12/2005 2:58:57 PM EDT

Originally Posted By MillerSHO:
I don't even know why people cared to bring "the same weight" into the debate.

When you flute a barrel you compare it to the same barrel that is unfluted.

You don't say, O this gov profile 16" A2 barrel has the same structure as my fluted 20"HBAR.

You compare it the similar barrel unfluted and leave it at that.

Geez guys.

derr derr



yeah that's what was throwing me off about the math argument in that other page
Link Posted: 10/12/2005 11:20:37 PM EDT
Link Posted: 10/13/2005 3:41:09 AM EDT

Originally Posted By Cape_hunter:
All you will ever need to know about fluting. More then most will understand however

Look HERE & HERE

Read up before you open your piehole folks!
CH



Thanks for the links. Verified what I suspected.
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