Fluted barrels - true purpose?

[Reverend Recoil]

"I still say fluting is a fad for most gun companies.  It makes the gun look cool and attractive with relatively little to be gained in weight reduction or barrel cooling for HUNTING rifles."

 
I agree.  Barrel cooling is also of no concern to high power rifle competition.  My AR15 service rifle barrels are heavy weight match grade and are not fluted.  I and many others shoot hundreds of ten-shot strings of rapid fire - 10 shots in 50-60 sec.  The barrel gets hot but this does no harm or increase the rate of throat erosion.  At 200 and 300yd the second string of fire is just as precise as the first.  Useful barrel life is 3000-4000 rounds regardless if fired slow or rapid.  At this round count I start to lose X’s at 600yd but can still clean the 200yd target.  The main reason I change barrels at 3000 shots is because I am still in the hunt for EIC leg points.
 
Barrel fluting is a waste of money.

[bilmac]

Rev,  So they are shooting the national match course with M16s now? When I did that we only shot the full 600 meter course with M-14s. We shot the 16 but only out to 400 m. and the target was a 5 point target.

I always thought the 16 had more potential than that but it seemed like the military wasn't interested in making it any better. 

[roper]

Here something from Krieger/lilja/Shaw/Score HI on their fluted barrels

http://www.kriegerbarrels.com/Fluting-c1246-wp3392.htm
http://www.riflebarrels.com/products/barrel_length_fluting.htm#flute
http://www.ershawbarrels.com/scb-fluted-barrels.php
http://www.scorehi.com/flute.htm

I'm sure their some here that have made rifle barrel and can comment on what Kreiger has posted.

Shilen has never like fluting here is there reason

http://www.shilen.com/faq.html#question8

[scootrd]

and another that states

Fluting and Barrel Stiffness: Fluting does not make a barrel stiffer. However, the weight reduction allowed by fluting permits you to start with a heavier barrel contour and end up at the same weight as an un-fluted barrel of a smaller diameter contour. This may result in slightly better rigidity, but extra stiffness is not something you can count on.

http://www.6mmbr.com/barrelfaq.html#24650

[roper]

and another that states

Fluting and Barrel Stiffness: Fluting does not make a barrel stiffer. However, the weight reduction allowed by fluting permits you to start with a heavier barrel contour and end up at the same weight as an un-fluted barrel of a smaller diameter contour. This may result in slightly better rigidity, but extra stiffness is not something you can count on.

http://www.6mmbr.com/barrelfaq.html#24650

I like the 6BR site and I post over there but what you have to look at is the guys who makes barrels vs someone option vs the guys who own 6BR and take money from Kreiger as a Sponsor.  I respect Shilen they have never fluted a barrel and it cost them money not offering it.  Thats kind of like McMillan when he  made barrels never heard a word from him about barrel break-in, after he sold the company he was  making  big deal about barrel break etc.

 

[SHOOTALL]

Try this image.  Picture the rim along the dial of a clock.  There is an arc on the rim between the number one and the number two.  Lets call that arc a positive arc.  Now go to the arc between two and three.  Invert the arc.  Do not change its radius at all, just turn it over. Let's call that "upside down arc" a negative arc.  Do that all around the clock.  Invert every other arc. 
Have you increased the exposed area along the rim of the clock dial?  No.  Have you decreased the greatest diameter of the rim of the clock.  No.  And since you did not actually modify any arc, you didn't change the circumference of the clock rim either.  You just changed the shape of the rim.
If you can picture this, now picture a rifle barrel as positive and negative arcs.  Since the negative arcs will require milling, the resulting barrel will be lighter, BUT, the surface area will not be changed at all. You have identical positive and negative arcs.
If you tacked on fins, or cut sharp groves like a spline, you could increase the surface area.  Flutes on rifle barrels are gentle rounded, shallow groves, mostly mirrowing the arc they were milled from.
Out of here - we have beaten this to death!  Wish I knew how to draw on my screen.  PM me with an email if you wish and I can scan a drawing and email it to you.  I'll attempt to take measurements from a Remington flutted 7-08 LVSF barrel.
Somebody on the forum explained it all to me a year or two ago.  Until then I thought the surface area was greatly increased too.

Anf if they were done that way it would look silly. Most start with a bbl and cut groves leaving flats , just saying...........the way decribed would leave a bbl that looked like a hippie flower from the muzzle end.

[mcwoodduck]

and another that states

Fluting and Barrel Stiffness: Fluting does not make a barrel stiffer. However, the weight reduction allowed by fluting permits you to start with a heavier barrel contour and end up at the same weight as an un-fluted barrel of a smaller diameter contour. This may result in slightly better rigidity, but extra stiffness is not something you can count on.

http://www.6mmbr.com/barrelfaq.html#24650

With the ridges would act as spines and add strength to the barrel over a standard barrel.  And I am not sure it would be weaker than the full bull barrel.
Much like an I beam is stronger than a thincker single peice of steel.

[Jay, Tx]

But an 8x8 I-Beam would not be any stiffer than an 8x8 piece of bar stock. it would weigh much less, thus the appeal.

Something that I was told many years ago by a very trusted machinist. He told me that the less machining one could do to a barrel after the bore was cut, the better the chance of the bore remaining more true. I was told, and it makes sense, since steel is grain oriented, it will have inconsistencies, and that machining relieves  any stresses present in the material if there are any present in the area being removed. The more one cuts out of a piece of material, the more they risk relieving these stress points. Now that doesn't sound too bad until you figure that the bore is already cut, and could be effected. Even if not when it's cold, after it's heated things could move even more than they originally would have.

For this reason, he would never have had a barrel fluted. I also so the point of a fluted barrel being no more rigid than a round barrel of an equal diameter. I do see how a fluted barrel of a larger OD could be more rigid, or just as rigid, as a smaller barrel while weighing close to the same. That makes sense.

as for the surface area thing. I have seen fluted barrels that no doubt gain some surface area. I see what the poster above is trying to relate, that if you merely dent a round object intermittently, then you really haven't changed the surface area any. But most flutes are cut a tad deeper, so some gain would be present. Enough to make a difference? I make no claims there.

[SHOOTALL]

a round pipe is stronger than the same size box tube all other aspects the same. Same could be true for sq tube vs H or I beams .

[evidrine]

If you have the patience to read all of this it may help add a little inisght.
 
http://www.varmintal.com/aflut.htm
 

[Keith L]

I have some of each, and they shoot well.  I really don't know which is best.

[SHOOTALL]

Two guns I have shot alot, one a 2506 rem 700 BDL w/ 24 inch thin bbl. straight from the factory no bedding or tuning . The other a 223 rem 700 BDL w/26 in bull bbl. The 25 has a wood stock ( the old one with ugly white spacers ) the 223 has a factory laminated stock as it left the factory.
The 25 will give one hole at 100 yards if I do my part. The 223 has never had as tight a pattern. The 223 has a 12X leo. scope and the 25 has a 3-9 VX2.
The 223 has been tried with everything from match to hand loads to hunting fact. loads. The 25 shoots 100 gr BT with 53 gr 4831 and BR primers in any case from win or rem. Some casesstarted life as 270 , 3006 or such and were sized for the 25.
 
 I think outside cosmetics of the bbl. are just that. Each rifle has to come together with all parts involved being near perfect to get an accurate rifle.