Pros and cons of fluting barrel

A couple of years ago for S&G I had a Remington factory barrel in 7SAUM fluted by a local smith.He did a first class job and the rifle shoots to the same POI as it did before fluting.I also have rifles with fluted barrels by Gaillard and Bevan King.They are extremely accurate.I can only speak for my own rifles but fluting on them has not been detrimental.It's a personal choice. My latest build is not fluted as it's a #2 contour barrel and I'd like it to have a bit of meat to it.:D Mur
 
remington jim said:
But it does not make a barrel less rigid from everything i can read about it ! That is a fact ! RJ :)
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Wrong. Fluting to remove weight leaves the barrel more rigid than turning it's diameter to achieve the same weight loss. The barrel does, however; come out less rigid than before it was turned or fluted. Fluting though is better to maintain rigidity than reducing the diameter.
NormB
 
I cut metal for a living and the answer AFAIK is if the machining is done in the proper order you will get the result you want. Lots of barrel makers make fluted barrels. What the smart folks at shilen were trying to say I think is that cutting flutes in one of their barrels after it is finished is a crap Idea. I would agree, stress in steel can make it do funny things. I have had ten inch rods come back from heat treat running out .040 . Far as rigidity goes; any time you take material off a piece it gets less rigid; there are no exceptions; all other things being equal. The myth of fluted barrels being more rigid than solid barrels of the same diameter come from a false statement made by a gunwriter a few years ago.
 
The factories that flute do so before heat treating? Does the average gunsmith redo the heat treat? And if he did, could he guarantee the barrel would still be straight? The notion of rigidity is a breakdown in nomenclature: the stiffness it provides is to control harmonics, like the boss muzzle thing, not the kind of stiffness for bending it over your knee. This was written about extensively in the 70's. Mr. Sorensen, do you remember those articles? Didn't Jim Carmichael cover flutes once?
 
What heat treating would that be?

Barrels are dead soft, else they would eat the very cutting tools that are supposed to be used to drill, ream, thread, turn to size, ream chambers,etc.

The few custom makers that heat treat at all, do so to normalize them, to take out any stresses that may have come about from working the material, or residual stresses left from the mill that produced the barstock.


Cheers
Trev
 
Lighter weight, rigidity, stresses, looks, like it, don't like it, added cost, changes in the bore, shoots as good, doesn't shoot as good... etc.

There will never be harmonious agreement to all of that...

One thing is certain though. it will never improve accuracy or all the short range center fire Benchrest shooters would be doing it... and it has the potential to negatively affect accuracy.

A match quality factory hand lapped barrel can be measured by those with the tools and knowledge before fluting and differences can be measured within the same bore after fluting... Any machining on the outside of a finished barrel will affect the bore dimensions.

And it will negatively affect accuracy very little with quality barrels and quality fluting. The potential accuracy loss will not be measurable in most cases as the rifle/cartridge/shooter combination isn't accurate enough to start with, to measure such small differences.
 
TrevJ: The treatment that would be is this. Steel barrels, typical chromoly jobs, are heat treated and stress relieved after machining and rifling. If they were "dead soft" the rifling wouldn't last anywhere near as long as it does. A mill spec M16/M4 or canadian C7 barrel is close to 30 Rockwell C scale. They are hardened but not to point of being really hard, stopping way before the formation of martensite. You can still cut and file them, but they are strong enough to handle the typical 50kpsi load, which ordinary steel won't handle, and even chromoly wouldn't without some kind of treatment. Just because you can hack away at it doesn't mean it isn't treated, and that happens after all else is done to it. The manufacturers allow for deformation from the process. There are diarrhea-inducing formulas for this, and if there is a red seal machinist on this board he could tell you all about them.(?) The original purpose for flutes was to control harmonics. Now it's just a cool factor/fashion statement.
 
Y'know that heat treated isn't the same as hardened, right?

The heat treating that all the barrels I have heard of, ended at normalizing for stress releif. The material hardness, if it is higher than a full anneal, is typically the state it arrived into the shop as bar stock.

Less magic in it than you seem to believe.

My money says that if the barrels you are using as an example, left the shop at RC30, then like as not, that was the hardness of the bar stock (ie: not very hard) when it came in, and the hardness testing would confirm that the machining processes would not have changed it.

Cheers
Trev
 
Annealing is a form of heat treating. Annealng, normalizing, hardening, tempering, are all forms of heat treating. 4150, as it comes from any supplier, is hot rolled and turns out in the nineties on the B scale, which compares to ten or twenty on the C scale, which gives it around 65k psi yield. Not tensile. So for a barrel to end up around 30, it has to have been treated somewhere along the line. Even 4140 at nearly 40 C is still very machineable. After treating, "annealing," barrels are softer than original state, but are still harder than "dead soft." After fluting, they should be treated. Sorry, annealed. Peace in the Middle East! http://www.riflebarrels.com/articles/barrel_making/details_of_accuracy.htm
 
As far as heat treatment goes, the kind of steel used, and the manufacturing process used are also factors. A lot of production barrels are hammer forged. Hammer forging creates great stresses in the barrel, and work hardens it. Going to be a very different critter than a one off custom stainless barrel. Some premium barrels are cryoprocessed for enhanced stress relief as part of the manufacturing cycle.
As far as the steel used in most civilian sporting barrels is concerned, the material is stress relieved prior to drilling, reaming and cut rifling. Button rifled barrels may be stress relieved before drilling and reaming, and will be stress relieved again after rifling.
 
For barrel makers, the best thing about fluting a pipe is the extra $150.00 they charge for doing a simple job.

Just ask Ted. LOL.
 
guntech said:
Lighter weight, rigidity, stresses, looks, like it, don't like it, added cost, changes in the bore, shoots as good, doesn't shoot as good... etc.

There will never be harmonious agreement to all of that...

One thing is certain though. it will never improve accuracy or all the short range center fire Benchrest shooters would be doing it... and it has the potential to negatively affect accuracy.

A match quality factory hand lapped barrel can be measured by those with the tools and knowledge before fluting and differences can be measured within the same bore after fluting... Any machining on the outside of a finished barrel will affect the bore dimensions.

And it will negatively affect accuracy very little with quality barrels and quality fluting. The potential accuracy loss will not be measurable in most cases as the rifle/cartridge/shooter combination isn't accurate enough to start with, to measure such small differences.
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Im not a gunsmith, so please take the following with a pound of salt.
TWK


If two barrels of the same weight one of which is fluted and one which is not fluted, are compared, the fluted one will have more rigidity? yes or no?
Will rigidity affect accuracy yes or no?

My point is, when you compare a larger barrel fluted down to the weight of a smaller barrel then the rigidity (which I would guess would affect accuracy for better or worse) will be increased.

However, if you take two barrels of the same diameter and flute one of them, the fluted barrel will lose rigidity, but also weight.

Therefore (the way I see it) is a fluted barrel of larger diameter but comparable weight has its beneifts in rigidity, and possibly accuracy, it woulds seem that way, as "bull barrels" seem to be used more with target/precision designed rifles.

And... the barrel of similar diameter, has the weight loss benefit for those interested in light rifles for long hikes.

I dont expect this will end the debate, but I dont see the light as to why fluting will become a thing of the past, unless it is in the interest of being unique (lets face it, the majority like the look of flutes)
 
fluting ?

cody c said:
Im not a gunsmith, so please take the following with a pound of salt.
TWK


If two barrels of the same weight one of which is fluted and one which is not fluted, are compared, the fluted one will have more rigidity? yes or no?
Will rigidity affect accuracy yes or no?

My point is, when you compare a larger barrel fluted down to the weight of a smaller barrel then the rigidity (which I would guess would affect accuracy for better or worse) will be increased.

However, if you take two barrels of the same diameter and flute one of them, the fluted barrel will lose rigidity, but also weight.

Therefore (the way I see it) is a fluted barrel of larger diameter but comparable weight has its beneifts in rigidity, and possibly accuracy, it woulds seem that way, as "bull barrels" seem to be used more with target/precision designed rifles.

And... the barrel of similar diameter, has the weight loss benefit for those interested in light rifles for long hikes.

I dont expect this will end the debate, but I dont see the light as to why fluting will become a thing of the past, unless it is in the interest of being unique (lets face it, the majority like the look of flutes)
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Well Hmmm !! :confused:
 
cody c said:
Im not a gunsmith, so please take the following with a pound of salt.
TWK


If two barrels of the same weight one of which is fluted and one which is not fluted, are compared, the fluted one will have more rigidity? yes or no?
Will rigidity affect accuracy yes or no?

My point is, when you compare a larger barrel fluted down to the weight of a smaller barrel then the rigidity (which I would guess would affect accuracy for better or worse) will be increased.

However, if you take two barrels of the same diameter and flute one of them, the fluted barrel will lose rigidity, but also weight.

Therefore (the way I see it) is a fluted barrel of larger diameter but comparable weight has its beneifts in rigidity, and possibly accuracy, it woulds seem that way, as "bull barrels" seem to be used more with target/precision designed rifles.

And... the barrel of similar diameter, has the weight loss benefit for those interested in light rifles for long hikes.

I dont expect this will end the debate, but I dont see the light as to why fluting will become a thing of the past, unless it is in the interest of being unique (lets face it, the majority like the look of flutes)
Click to expand...

Yes Cody you are right, and I can support that thread as a 35 years in the bussiness general machinist tradesman.
 
cody c said:
Im not a gunsmith, so please take the following with a pound of salt.
TWK


If two barrels of the same weight one of which is fluted and one which is not fluted, are compared, the fluted one will have more rigidity? yes or no?
Will rigidity affect accuracy yes or no?

My point is, when you compare a larger barrel fluted down to the weight of a smaller barrel then the rigidity (which I would guess would affect accuracy for better or worse) will be increased.

However, if you take two barrels of the same diameter and flute one of them, the fluted barrel will lose rigidity, but also weight.

Therefore (the way I see it) is a fluted barrel of larger diameter but comparable weight has its beneifts in rigidity, and possibly accuracy, it woulds seem that way, as "bull barrels" seem to be used more with target/precision designed rifles.

And... the barrel of similar diameter, has the weight loss benefit for those interested in light rifles for long hikes.

I dont expect this will end the debate, but I dont see the light as to why fluting will become a thing of the past, unless it is in the interest of being unique (lets face it, the majority like the look of flutes)
Click to expand...

I would say the barrels would have to be the same length and same caliber to compare rigidity.
 
Headcase said:
Annealing is a form of heat treating. Annealng, normalizing, hardening, tempering, are all forms of heat treating. 4150, as it comes from any supplier, is hot rolled and turns out in the nineties on the B scale, which compares to ten or twenty on the C scale, which gives it around 65k psi yield. Not tensile. So for a barrel to end up around 30, it has to have been treated somewhere along the line. Even 4140 at nearly 40 C is still very machineable. After treating, "annealing," barrels are softer than original state, but are still harder than "dead soft." After fluting, they should be treated. Sorry, annealed. Peace in the Middle East! http://www.riflebarrels.com/articles/barrel_making/details_of_accuracy.htm
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FWIW I have some barrel steel here that I ordered a few months ago and it is rifle barrel quality steel it comes at a hardness of 28-32 on the rockwell c scale is double stress releived and has gone through testing to make sure it is perfectly homogenous.
It is some kind of x-ray in a way where they check to make sure there are no laps or impurities .
As far as fluting this is done after the barells are rifled then stress releived then profiled and lapped, there is no stress releif done after fluting because at this point the barrel has already been stress releived.
Imo the only way that flutting might reintroduce stress is if you would use a dull cutter and fed it fast .
 
Coyote, I don't disagree. If nobody minds, getting back to the original question by ryanshaw, so far the most poignant observation is that benchrest shooters don't bother with it. They only deal in reality, and what works. They don't care if there's a scientific basis or not, nice if there is, but really only want results. They try everything, no matter how outlandish, and none seem to bother with flutes. If flutes really made a difference, they'd flute everything. Put the money into other things that are known to make a difference.
 
coyote said:
FWIW I have some barrel steel here that I ordered a few months ago and it is rifle barrel quality steel it comes at a hardness of 28-32 on the rockwell c scale is double stress releived and has gone through testing to make sure it is perfectly homogenous.
It is some kind of x-ray in a way where they check to make sure there are no laps or impurities .
As far as fluting this is done after the barells are rifled then stress releived then profiled and lapped, there is no stress releif done after fluting because at this point the barrel has already been stress releived.
Imo the only way that flutting might reintroduce stress is if you would use a dull cutter and fed it fast .
Click to expand...

All machining operations induce some stress you can minimise it but you can't eliminate it. BTW this is by far the most interesting thread I have read in a while.
 
Looking inside a fluted barrel with the borescope we see that the firecracking is worse in the area where the material is removed on a fluted barrel, where as it is more evenly distributed in a normal barrel.
This I believe is due to the fact that the thinner part of the barrel where material has been removed heats up faster than the non fluted portion.
The fluting proponents claim that a fluted barrel cools faster, but physics in immutable in the for every action their is an opposing reaction so by that logic it must also then heat up faster, but more importantly the barrel then would heat unevenly.

As for the 2 to 3 ounce of weight saving, if it is that critical someone needs more time at the gym.
 
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