Fluting Barrels

[muleman69]

"I" beams are stronger and stiffer than a piece of solid steel of the same dimensions, same with other types of structural steel. A fluted barrel of the same diameter is stiffer than a solid one of the same diameter.

Take a piece of 1" steel rod, ten feet long, lay it on two horses, one positioned at each end, check the sag. Do the same with a piece of 1" steel rod that is fluted, measure the sag. The solid will sag more. Which one is more stiff?

Still not convinced? How many suspension or other bridges are built with SOLID steel?

I can see what you are saying, The ridges between flutes act as stiffeners.Just Read Richards post from above and from his test he shows the barrel's have more flex?

 

[Bart B.]

The diameter of tubes formed from rolling them up will be the same, as will their weight. The only difference is one tube is corrugated and one isn't. Therefore - - all else being equal, the corrugated one is the stiffer of the two.

I don't think the diameters will be the same. Corrogating a sheet reduces its dimension at right angle to the folds.

 

[Bart B.]

I can see what you are saying, The ridges between flutes act as stiffeners

Right you are.

The technical term is "buttress," exactly like the ones on the outside walls of old churches and castles.

Fluting reduces the width of half of them around the barrel.

 

[ED3]

Here is some of that "play on words" thing I was referring to....you could say that hot gases DO NOT conduct anything, hot gases are present and the surface of the bore tries to reach an equilibrium. I believe there is some scientific law regarding this action. I apologize for my current inability to quote it. Every element has a thermal number, the hot gas being the "source" to heat the barrel steel we are not concerned with it's thermal number...we don't care how long it took the heat to go thru the gas itself. Maybe a better way of saying it is that the temperature of the gas is not the problem, it how hot the steel gets that is.
One would hope fluting the OD has no effect on the bore...if it did then certainly no one in their right mind would pay to have it done!!! You are correct {at least I think so} that fluting has no effect on thermal transfer through the barrel wall itself, but it very definitely affects the outer surfaces ability to dissipate said heat once it gets to the surface....again, think of radiator fins. All this is of course given the fact that we have functional flutes and not just cosmetic ones. Flutes or other heat dissipating enhancements aside, there is also this matter of mass itself...a 6 pound piece of steel, no matter the thermal number, will always take longer to cool than a 3 pound piece.

Thermal energy transfers from a material of higher energy to to a material of lower energy by three means: Radiation, convection, and conduction.

My point was/ is that if fluting doesn't alter the bore, or the transfer of heat from the escaping gasses to the barrel material.

 

[BenPerfected]

I have to ask a question, is more important to look cool, and cool faster? or to be more accurate???

Merry Christmas to all......

Yes

 

[butchlambert]

Hart’s offers it for both hunting and BR barrels.

Tim, notice I said most.

 

[fyrewall]

The article regarding barrel vibes in the barrel tip deflection post has some application. Fig 1. in the article (the stuff by the mechanical engineers from Turkey) is descriptive. My thinking is a fluted barrel having a greater diameter will be stiffer than a barrel having less diameter but of equal weight. Of two barrels of equal diameter the non-fluted barrel will be stiffer because there is more mass subjected to vibe stresses.

For me there is no practical advantage in fluting. There might be an increase in surface area allowing more cooling but also there is a reduction in mass for heat absorbing. The increase of area from fluting is not that great.

Think of having a rifle having press fit aluminum fins that would act to increase cooling area. The aluminum would be relatively light and conduct heat better than steel and provide a great area increase for cooling. The aluminum fins would have a diameter from 3 to 6 inches and be spaced about 1/2 inch apart. Stocks would need to be radically designed to allow use of scope sights and the scope mounts would be up to almost 1 foot high. The fins being perfectly balanced would allow uniform barrel vibes promoting optimum velocity nodes. This would be one ugly rifle (look like some kind of ray gun) - awkward, and difficult to use for short range targets. Sales would be terrible and going bankrupt would be a certainty. But this might provide a tiny advantage for those seeking some ultimate goal.

 

[savagedasher]

Wouldn’t a barrel of equal weight and lingth the fluted barrel be stiffer ? Because it diameter would be larger?

 

[richard]

You guys need to compare apples to apples.
If you take the SAME bbl it will have more flex when fluted.
Changing the dia will change stiffness. Two bbl.'s of the same weight and length the fluted one will have less flex because of the increase of the diameter. Fluting by itself does not increase stiffness.

Richard

 

[Bart B.]

Two barrel makers told me that sometimes fluting finished barrels...,

...button rifled, would increase bore diameter.
...hammer forged, would decrease bore diameter.
...cut rifled, cause little, if any, change in bore diameter.

All just under the flutes. Which is why proper stress relieved fluted barrels can drive pins. Pins are smaller than tacks.

Note the metal in the top half of a horizontal barrel resists stretching, the bottom half resists compressing. When fired, the metal switches back and forth between them as well in the horizontal but to a lesser degree. Remove some of that metal and there's less resistance to stretching and expansion; regardless of the forces applied.

 

[BenPerfected]

Happy Holidays Bart,
If you would, please add more comments on the benefit of stress relieving a fluted barrel. I ask as all of my 1.250 barrels are fluted and set up with a tuner.
Ben

 

[jimmymac]

Richard is the guy you need to talk to about fluted barrels and tuners Ben. He’s tested a lot.

 

[fyrewall]

The article regarding barrel vibes in the barrel tip deflection post has some application. Fig 1. in the article (the stuff by the mechanical engineers from Turkey) is descriptive. My thinking is a fluted barrel having a greater diameter will be stiffer than a barrel having less diameter but of equal weight. Of two barrels of equal diameter the non-fluted barrel will be stiffer because there is more mass subjected to vibe stresses.

For me there is no practical advantage in fluting. There might be an increase in surface area allowing more cooling but also there is a reduction in mass for heat absorbing. The increase of area from fluting is not that great.

Think of having a rifle having press fit aluminum fins that would act to increase cooling area. The aluminum would be relatively light and conduct heat better than steel and provide a great area increase for cooling. The aluminum fins would have a diameter from 3 to 6 inches and be spaced about 1/2 inch apart. Stocks would need to be radically designed to allow use of scope sights and the scope mounts would be up to almost 1 foot high. The fins being perfectly balanced would allow uniform barrel vibes promoting optimum velocity nodes. This would be one ugly rifle (look like some kind of ray gun) - awkward, and difficult to use for short range targets. Sales would be terrible and going bankrupt would be a certainty. But this might provide a tiny advantage for those seeking some ultimate goal.

On to the MKII version of the ugly aluminum finned rifle - thread the 1/4 inch thick donut hole shaped fins and screw them on to stepped barrels having matched threads; aluminum cylinders would separate the 1/4 inch thick fins.

Sure makes sense on button vs. hammer vs. cut. I can see that barrel expanding as the button is dragged through it and not having complete recovery. Shrinking by pounding the barrel to conform to some mandrel. Nice smooth cuts, no displacement.

 

[Bart B.]

If you would, please add more comments on the benefit of stress relieving a fluted barrel.

The only way in know of to totally minimize all stress in a barrel is to barely torque it into the squared up receiver, store it perfectly vertical and never shoot it.

Shoot it horizontally and stress from drooping and firing starts.

 

[Tim s]

Tim, notice I said most.

My post, Simple point of information.

 

[jdh47]

Ed Shilen said that they did tests on fluting their barrels and decided that for their button rifled barrels it could cause problems as the barrel heated up. He didn't get into anything about any heat treating and such. He said if you want to flute a barrel then get a cut rifled barrel.

If you like fluting then by all means do that. There are plenty of people that can do a good job of it. This has been argued and discussed a lot over the years. All I know is what I hear and I respect Ed Shilen. It does raise the cost of the barrel and it can be detrimental if done wrong. I have seen plenty of badly fluted barrels and I've seen some superbly done ones as well. I suppose the test is in the results. Some like them and some don't. I never could justify the extra cost.

 

[Bart B.]

By the way, Bart B., I can understand why some prefer to remain anonymous by not using their full name but I would appreciate an e-mail telling me a little more about yourself.

Check my profile.

 

[butchlambert]

Check my profile.

Bart, I think you are a pretty smart feller, but your profile says nothing. Not jumping you at all, but.

 

[butchlambert]

Check my profile.

Bart, I think you are a pretty smart feller, but your profile says nothing. Not jumping you at all, but.

 

[butchlambert]

Needed to post this of Skip's group with his fluted Shilen barrel.