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View Full Version : And the stupid question for this week is....


Bullwinkle
05-06-2011, 12:30 PM
For you tactical/precision rifleman types:

Perhaps I'm overthinking this, but if a bull barrel is conducive to better accuracy (or is that a myth?), then wouldn't fluting it detract from the accuracy by taking away part of what makes a bull barrel a bull barrel? :confused: Or put another way, is the fluting simply a compromise between weight vs accuracy?

Just trying to figure out what I want to (eventually) put on my .308 AR build. I'm leaning toward a fluted barrel, but I'd rather carry the extra weight if the fluting is going to detract from accuracy. [Of course, quivering muscles from dragging a heavy weapon around isn't exactly conducive to accuracy, either. ;)]

Thanks, guys & gals.

thrillhouse700
05-06-2011, 12:38 PM
I don't think fluting detracts from accuracy. I have seen a few guys at the range with really awesome groups with fluted barrels. The way I see it the bull barrel has more rigidity and the flutes should not take away from that as long as its done right and still retains the ridges at full "bull" diameter.

Supposedly they cool faster due to increased surface area..........

I'm not an expert by any means that's just my logical take on it. Prob best to contact ar15 barrels and he could tell you for sure.

Vacaville
05-06-2011, 12:45 PM
I always thought the reasons for getting a bull barrel were to have added weight to reduce recoil so you can keep on target, and to take longer to heat up, which gives you more shots before your accuracy goes wonky.

I've been thinking the same thing - that fluting goes against the purposes of having a bull barrel. Why not just get a regular contour and save the money? But I'm no expert, and will be interested in what other people have to say.

goodlookin1
05-06-2011, 12:47 PM
Fluting is supposed to:

- Take off weight without losing any stiffness
- Create more surface area to cool down barrel faster
- Look cool

Whether they do much performance wise is beyond my knowledge and ability to test.

LeatherNuts
05-06-2011, 12:57 PM
I may be talking out of my @$$ here, but I would think a fluted barrel would behave like any other metal that has raised areas and be MORE rigid. If you take a flat peice of metal and try to bend it, it goes farely easy. Now bend the metal lengthwise at a 90 degree and try again, far harder. I would venture to guess that a fluted barrel would give you better accuracy like a bull, but with the benefits of being lighter, cooling quicker, etc.

rero360
05-06-2011, 1:11 PM
Having a bull barrel serves a number of purposes, a bull barrel will be more rigid than say a sporter/ hunting profile barrel of the same length. Additionally, because the bull barrel has more material for the same given length, it will take longer for the barrel to heat up to the point that any stresses in the barrel will cause it to start walking the shots or opening up the groups.

Conversely the bull barrel will also take longer to cool down.

Two barrels of the same length, and same contour, one fluted and the other not, the fluted one will be lighter and have a greater surface area. If the fluting was done right it won't induce any additional stress to the barrel so it should remain just as accurate as a non fluted barrel. The ability of the barrel to cool faster due to the increased surface area is still up to debate, some people believe it does, others don't. I'm personally in the camp that it does, but not enough to be actually beneficial. Basically a properly fluted barrel will be lighter than a normal bull barrel but will be more rigid than a skinny barrel.

Proper form, application of the shooting fundamentals and having the rifle fit you properly will do more for your accuracy and handling recoil than any barrel length or weight. But yes, a heavier rifle will have lower felt/ perceived recoil than a lighter rifle, all other variables being the same.

Basically, it all comes down to personal preference, what you plan to do with the rifle, your physical strength and abilities and how you want it to look.

killshot44
05-06-2011, 1:12 PM
Fluting just reduces weight and may aid in cooling.

Look at what the Benchrest guys shoot; thick barrels with little taper and no flutes.

wash
05-06-2011, 1:12 PM
Fluted barrels are not as stiff as the same profile without fluting. What makes them more accurate is that they are stiffer than a plain profile barrel of the same weight or in other words they are lighter than a plain barrel of equal stiffness.

With equal stiffness and lighter weight, the resonant frequency rises which means the barrel won't whip as much when a shot is fired. That is what makes a fluted barrel more accurate.

kozumasbullitt
05-06-2011, 1:15 PM
I may be talking out of my @$$ here, but I would think a fluted barrel would behave like any other metal that has raised areas and be MORE rigid. If you take a flat peice of metal and try to bend it, it goes farely easy. Now bend the metal lengthwise at a 90 degree and try again, far harder. I would venture to guess that a fluted barrel would give you better accuracy like a bull, but with the benefits of being lighter, cooling quicker, etc.

In your analogy you are doubling the actual mass of the material when in reallaity with fluting you are taking away mass. I am not sure if fluting reduces barrel strength or not but if I took 2 wodowries and fluted one and not the other, the fluted one would break with less force.

LeatherNuts
05-06-2011, 1:21 PM
In your analogy you are doubling the actual mass of the material when in reallaity with fluting you are taking away mass. I am not sure if fluting reduces barrel strength or not but if I took 2 wodowries and fluted one and not the other, the fluted one would break with less force.

I knew there had to be a reason my guidance counselor didnít push me towards being a structural engineer.:D

CK_32
05-06-2011, 1:45 PM
Bull barrels add weight for muzzle flip. And have more mass to heat up which makes it hold off heat longer for more shots...

And a fluted barrel is some what where the myths lye. it foes reduce some weight but hardly... And one myth is that it makes the barrel ribbed and gives it a structure and makes it firmer or stonger than a non fluted barrel.. Also it has been said it disperse heat better but that would only be because it has less mas to cool off but would also stand for it being able to heat up faster.

In all it reduces (some slight amount) of weight and just looks cool. Other than that I havnt seen any defenative difference of it increasing any performance or a rifle barrel other the same standard non flueted kind.


And for the weight your aiming for... You'll notice more weight difference in a different lighter stock or a smaller scope than you will with weight reducing from fluting. It's a few ounces at most varies by barrel length of course but with the standard 18 to 22" barrels it won't be much.

Just a cool factor.

chicoredneck
05-06-2011, 1:56 PM
Fluting is supposed to give all the benefits of a bull barrel while keeping it lighter. "Supposed to" being the key phrase.

Think of your barrel behaving smilar to a garden hose. The barrel sags under it's own weight, so when you shoot it is like turning the water on to your garden hose. The barrel straightens out under the imense pressure caused by firing.

A bull barrel has more rigidity so there is less sag.

A fluted bull barrel is supposed to have the same regidity with less weigh which equals even less sag.

Properly fluted barrels can be very accurate, but can be less consistent than an un-fluted barrel. The reason being is that an un-fluted barrel has very consistent barrel harmoniocs (the frequency of the vibration of the barrel caused by firing). The fluting process can cause the barrel harmonics to be more erratic, especially as the barrel heats up from firing, because of the incosistencies introduced to the barrel through the fluting process.

Overall, two barrels of equal contour and quality, one being fluted and one being non-fluted, the fluted barrel will be more accurate for single shots, but as the shooting continues and the barrels heat up the non-fluted barrel will be more consistent.

Another way to increase barrel rigidity is to shorten the length of your barrel as this reduces the amount of sag.
The general rule being that the longer your barrel the thicker it's profile must be to equal a shoter barrel of a more slender profile.


Spiral fluting causes reduced accuracy and reduced regidity. The sprials act like "hinges" that the barrel whips around during firing.

Some quick reading. There is a lot of information at the variouse BR websites that go into further detail.

http://www.rifle-accuracy.com/harmonics.htm
http://www.varmintal.com/aflut.htm

FeuerFrei
05-06-2011, 2:14 PM
This should help answer your questions... http://www.shilen.com/faq.html

chicoredneck
05-06-2011, 2:27 PM
This should help answer your questions... http://www.shilen.com/faq.html

Excellent link explaining the downfalls of fluting.
But there are positives too, especially if you are only shooting cold bore.

Uriah02
05-06-2011, 2:59 PM
This should help answer your questions... http://www.shilen.com/faq.html

From what I gathered of their reasons against fluting was the potential for performance in benchrest shooting being degraded, not necessarily the effect. I can understand not wanting to take chances on something as precise and static as benchrest but for almost all other applications I am curious of the level of risk and degradation fluting may cause.

chicoredneck
05-06-2011, 3:19 PM
For normal hunting practices fluting, when done properly, is a benefit and not a detractor.

The reason benchrest is mentioned is because of the amount of shooting. As stated before, if the barrel is properly fluted cold bore shooting can be just as accurate, if not more accurate (because straight fluted barrels are more rigid than non-fluted barrels of the same profile) but, after extended shooting the barrel heats up and thats when the inconsistencies become a factor as the barrel swells.

Fluting that has not been properly done can be a huge detractor.

IrishPirate
05-06-2011, 3:25 PM
I always thought the reasons for getting a bull barrel were to have added weight to reduce recoil so you can keep on target, and to take longer to heat up, which gives you more shots before your accuracy goes wonky.


^this^ +2 points and double word score for using "wonky"


depending on the style of fluting it will either add rigidity and help cool, or just help cool. Both things improve accuracy. If a barrel is thick enough you can have a fluted bull barrel. The extra weight will help keep it on target and take longer to heat up, the flutes will dissipate heat and possibly add rigidity. Sounds like a winning cocktail!

Fluting is used mostly when people want the increased accuracy but not the weight. bull barrels make their way onto "bench guns" most often (AFAIK). I personally like the look of the fluted barrel better and would rather have a gun that keeps cool longer....there are other devices to keep you on target.

IrishPirate
05-06-2011, 3:33 PM
From what I gathered of their reasons against fluting was the potential for performance in benchrest shooting being degraded, not necessarily the effect. I can understand not wanting to take chances on something as precise and static as benchrest but for almost all other applications I am curious of the level of risk and degradation fluting may cause.

from what i gathered, they were talking about having a normal barrel fluted, not getting a fluted barrel. I would agree that fluting a barrel not made to be fluted would probably be a bad thing. But factory made fluted barrels start out larger and are trimmed/fluted to the right size. That process would seem to be much safer and much more effective IMHO.

chicoredneck
05-06-2011, 3:42 PM
from what i gathered, they were talking about having a normal barrel fluted, not getting a fluted barrel. I would agree that fluting a barrel not made to be fluted would probably be a bad thing. But factory made fluted barrels start out larger and are trimmed/fluted to the right size. That process would seem to be much safer and much more effective IMHO.

All factory barrels (at least the last I heard) start out un-fluted and are made to a certain contour. The fluting is added afterward by either the barrel maker or the gunsmith. To my knowledge there are no barrels made specifically to be fluted.

rocknut
05-06-2011, 6:47 PM
A fluted barrel is less rigid than a non-fluted barrel of the same profile. The benefit of the fluted barrels is that they are more rigid than another barrel of the same weight. Its an accuracy vs. weight thing.

Bullwinkle
05-09-2011, 8:49 AM
Thank you, all.

Sounds like maybe this wasn't as stupid a question as I thought it was going to be... which makes me feel better. :)

FYI - I could care less about "cool factor" (guess I'm just too cool for that nonsense :coolgleamA:); I'm solely interested in performance. After reading your replies, I'm still leaning toward the fluted barrel, but not nearly as much as I was. I'll need to think about this a lot more. Might boil down to a cost/reward business decision... is the perceived advantage worth $65 more (based on DPMS list prices)? Or would that $65 be better spent elsewhere, like threading the barrel for a muzzle device or buying a better scope? Boy, I'm talking myself out of the fluted barrel more and more even as I type!

Again, thanks to everyone. All of life's decisions should be this difficult, huh? ;)