weight saving by fluting barrel

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Any idea on (roughly) how much fluting will reduce barrel weight? I'm thinking about getting a .50 cal Knight muzzleloader done.

RC
 
It is entrely relative to the barrel size, diameter and weight. You do not save a great deal of weight generally. For your purposes, I suggest simply going as light as you can with the contour.
 
I have 5 or 6 fluted rifle barrels in various calibres and while I've heard that you can drop weight to the amount of one contour size,I'm inclined to believe that fluting is in most cases more for cosmetics than weight loss.All the fluted barrels I have are very accurate,including 1 factory Remington.The others are Gaillard and King barrels and would I think be accurate in any case! Mur
 
You can figure it up by finding; the average area of cut in sqare cm X lenght of cut in cm X number of flutes X 7,8 and the result will be in grams of metal saved b/c every cc equals 7,8 grams of steel. It's not that difficult really.
 
It depends on the size, depth, and length of the flutes. We did a heavy octagon muzzleloader barrel for a customer and it made a huge difference in weight, but with the octagon profile the fluting was removing more material than is would on a round barrel.

KAgraphics031.jpg
 
I think its generally going to be mostly a cosmetic thing for most people.

It might not take a lot of weight but it will make a considerable difference to the surface area and assist with cooling quite a bit. Similar to the fins on a Thompson SMG.
 
vagrantviking said:
I think its generally going to be mostly a cosmetic thing for most people.

It might not take a lot of weight but it will make a considerable difference to the surface area and assist with cooling quite a bit. Similar to the fins on a Thompson SMG.
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Actually, most fluting doesn't add enough surface area to make much of a difference as far as cooling goes. You'd need to make several deep and narrow grooves to get decent cooling. It can shave a lot of weight though, that octagon barrel lost just over a pound.
 
Fluting does not substantially affect cooling. You would be better served by parkerizing/mang-phos the barrel.

FYI, as a long range precision shooter I would never opt to flute anything but a good quality cut rifled barrel. I cringe and fluting buttoned or hammer forged barrels. For your application and considering the size, it would be less of a problem, but I personally never use fluted barrels.
 
Obtunded said:
FYI, as a long range precision shooter I would never opt to flute anything but a good quality cut rifled barrel. I cringe and fluting buttoned or hammer forged barrels.
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I couldn't agree more. Buttoned and hammer forged barrels have residual stress left in metal after rifling but cut rifled ones don't. Ask me how I know....I did flute couple of Mick's barrels (cut rifled) and after the process they stayed as straight as before, not even the hint of stress in them.
 
kingarmory said:
Actually, most fluting doesn't add enough surface area to make much of a difference as far as cooling goes. You'd need to make several deep and narrow grooves to get decent cooling. It can shave a lot of weight though, that octagon barrel lost just over a pound.
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That octagon barrel is a seriously strange application of fluting to my mind.

Wouldn't it be more cost effective to build another gun with a slimmer barrel to start with? If there is enough metal to flute like that a person could have started out with a barrel 1/8 inch (or maybe even more) narrower and saved at least as much weight.

I haven't calculated anything but I would have thought that the flutes would easily add 15-20% to surface area. The cooling effect isn't going to be a big concern for most of the guns that people like to flute anyway. I wonder if a fluted barrel would have very different vibration characteristics than a round barrel?
 
There is a barrel weight calculator at the Pac-Nor link below. Just do it once without flutes, and then again with flutes to see the difference.

http://pac-nor.com/cgi-bin/pnb/bweight.cgi

The theoretical benefit of fluting is that for the same weight a fluted barrel will be stiffer, and the vibration amplitude less. That said, I would suggest the effect is mostly cosmetic.

Some button rifle manufacturers like Shilen do not flute their barrels. Others like Hart do, but they do the final lapping after the flutes are cut. The reason is that fluting relieves some of the stress that button rifling creates, and can cause minor changes to the bore diameter. By doing the lapping last they can control final bore size even though the barrel has been fluted.
 
vagrantviking said:
That octagon barrel is a seriously strange application of fluting to my mind.

Wouldn't it be more cost effective to build another gun with a slimmer barrel to start with? If there is enough metal to flute like that a person could have started out with a barrel 1/8 inch (or maybe even more) narrower and saved at least as much weight.
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It was a custom barrel for a T/C Encore, the company that builds the barrels didn't have any other options on barrels that length. He brought it in and wanted it lightened since he was going to use it for hunting, obviously fluting was the only viable method. It made the barrel a LOT more manageable, but the machining time to cut flutes that deep on a 32" barrel was considerable. I think we only charged him $150 though, which isn't bad for the amount of machine time required.
 
It would be interesting to actually run the calculations on how much better the cooling actually is on a fluted barrel. Unfortunately, I slept through most of my thermodynamics class in university and sold the textbook to buy beer.

My understanding of the barrel harmonics is that an odd number of flutes would be better. It has to do with the moment of inertia of the cross sectional area of the rifle, an odd number of flutes should have a larger moment of inertia, and therefore its stiffness should be increased, when two barrels of equal cross sectional area (and therefore weight) are considered.

Keep in mind I'm not a gunsmith, and this is based upon pure theoretical material mechanics (which I am also a bit rusty on). And we all know theory and reality can be two totally different things.
 
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Ron AKA said:
The theoretical benefit of fluting is that for the same weight a fluted barrel will be stiffer, and the vibration amplitude less. That said, I would suggest the effect is mostly cosmetic.
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Those benefits are not theoretical and no cosmetic. Large number of deep and narrow fluting does stiffen the barrel, lessens the amplitude of vibration and accelerates the cooling of the barrel. I agree, those factory fluting like Rem & Sendero's are only cosmetic. The competiton shooters when having the weight limits on their riffles and shooting 10 shots as fast as they can pull the trigger (hot, hot barrels) often opt for fluting to have an advantage.
 
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