Math, science, and barrel fluting

[Trevor60]

here is my understanding

Barrel's of the same weight fluted are stiffer
Barrel's of the same diameter non-fluted are stiffer

If you take your exampled of a tapered barrel and cut steel out to make the flutes you lose rigidity. However
If you took a straight tapered barrel and and removed steel to match the weight of your profile barrel
fluted barrel greatly improve the stiffness.

I think fluting has merits for all the reasons previously posted BUT cost is a real consideration.

Here is a discussion on here a couple years back.
http://forum.accurateshooter.com/threads/fluting-barrels.3967683/page-2

Cheers
Trevor

 

[mensajd]

Between finite element analysis and empirical cantilever beam analysis, why is this discussion even a thing? The truth is out there.

 

[skeeljc]

Most barrels are fluted AFTER they are drilled and rifled. If the barrel is not fully stress relieved the flutes can alter the straightness and possibly the precision.

 

[Hohn]

If I ever got a barrel fluted, it would actually be more like a golf ball dimple pattern. You know it makes it more aerodynamic.

Kidding aside, an isogrid just says "I'm an engineering nerd that knows what these are and also smart enough to know they aren't helping me at all and I'm doing it just to make an ironic statement." Sort of engineer meets hipster.

So I'd do an isogrid.

 

[Shrek]

OP calculated @4oz weight reduction. That’s a quarter pound. I don’t know how many here have hiked up and down the mountains for days but I have. A quarter pound here and a quarter pound there and pretty soon you just can’t make it up the mountain on day five. Everything is a trade off. I want a lighter rifle but want the velocity performance of a longer barrel. I flute mountain rifle barrels. Anyone who doesn’t think a quarter pound is a big deal hasn’t hunted mountains living from a backpack.

 

[jelenko]

Right. Depends on the application/use.

 

[INTJ]

This sounds contradictory, can you expand some on your meaning?

If you take perfectly straight fluted and non-fluted barrels of the same dimension, mount them horizontally and measure the droop at the muzzle, the fluted barrel would not sag as much since it is lighter while having the same shank.

However, if you put those same barrels under a bending moment, the non-fluted barrel would require more force for the same amount of bending movement as the fluted.

 

[46and2]

there has been some work done that showed the diameter of the bore changes when the barrel gets fluted or the diameter under the flutes is different from the rest of the bore. dont know if this is true or not but its enough reason for me to never want a fluted barrel. i

I have heard this before but no evidence was presented. I've thought about it many times since.
If the bore gives under the flutes would the same principle also make the bore of a pencil thin barrel give just the same.

 

[davidjoe]

Nearly all of my barrels are MTU style tapered. Neither fluted nor bull. The resonating frequency must change along the entire length if the diameter does.

There was an interesting piece in Firearms News this month. I copied only a fraction of it.






“The barrel features a heavy profile design with spiral flutes in three sections along its length. The spiral fluting both increases surface area while reducing the weight of the barrel. The spacing, thickness, and tapered height of the fluting were all optimized through testing. In addition, the fluting shaves .25 pounds off the barrel. The US Army claims the design allows firing at temperatures as high as 909.5 degrees F, provides a higher cook-off limit, prevents barrel droop, increases the barrel life, and allows an increased sustained rate of fire.

What is interesting is the US Army has been granted two patents on the design. They have received a 15-year design patent and a 20-year utility patent. The US Army states they believe the design may be useful on other weapon systems and is willing to license the design to commercial industry. Brian Metzger, a senior technology manager at TechLink, is facilitating licensing discussions for companies interested in producing the barrel. “The design patent reinforces the utility patent, makes it a complete package for a licensee,” Metzger stated on July 8th, 2020.”

 

[hoz53]

Nearly all of my barrels are MTU style tapered. Neither fluted nor bull. The resonating frequency must change along the entire length if the diameter does.

There was an interesting piece in Firearms News this month. I copied only a fraction of it.


View attachment 1190357



“The barrel features a heavy profile design with spiral flutes in three sections along its length. The spiral fluting both increases surface area while reducing the weight of the barrel. The spacing, thickness, and tapered height of the fluting were all optimized through testing. In addition, the fluting shaves .25 pounds off the barrel. The US Army claims the design allows firing at temperatures as high as 909.5 degrees F, provides a higher cook-off limit, prevents barrel droop, increases the barrel life, and allows an increased sustained rate of fire.

What is interesting is the US Army has been granted two patents on the design. They have received a 15-year design patent and a 20-year utility patent. The US Army states they believe the design may be useful on other weapon systems and is willing to license the design to commercial industry. Brian Metzger, a senior technology manager at TechLink, is facilitating licensing discussions for companies interested in producing the barrel. “The design patent reinforces the utility patent, makes it a complete package for a licensee,” Metzger stated on July 8th, 2020.”

thats interesting. We havent heard the last of the fluting issue for sure. If the barrel life deal proves to be true for what i need that mite be a game changer. i guess we shall see thanks

 

[mr45man]

fluted barrels are just Kool.

 

[hoz53]

I have heard this before but no evidence was presented. I've thought about it many times since.
If the bore gives under the flutes would the same principle also make the bore of a pencil thin barrel give just the same.

i dont know of any hard evidence either but i dont think ill do a test either and i bet i dont have enough skill to tell the difference, accuracy wise, between fluted and nonfluted so no reason paying or putting the effort in to get flutes.

 

[epc308]

Technically, aren’t flutes called lands...

Asking for a friend. [

5 or 10 years ago this forum was the precision shooting forum. The authority on precision shooting. All threads were full of serious knowledge. I learned a lot and mostly kept my mouth shut.

Now this forum is overrun with shooters of all kinds who think they know what they are doing. Different disciplines do not have the same accuracy expectations, reloading techniques, gun handling tecniques, cleaning methods in fact very little in common. Three people on a thread with completely different shooting styles what do you expect. I have thought about just signing off but i see so much bad information being offered to new shooters I stick around. Sometimes I get disgusted and don't come back for a few weeks but it seems I always come back.

The website is named Accurate Shooter, not Precision Shooter. I have no idea how or where it was 5-10 years ago, as I wasn't here.
Accuracy is in the mind of the individual shooter. For some it is stacking bullets, for some it is minute of beer can.
You are correct, there may be a wide range of experience, shooting style, and shooting ability in any given thread.
Sometimes that less experienced individual, without a preconceived notion, just might bring much needed insight to the subject.
I freely admit I don't know it all, but I like to read, and I like to learn. This forum helps with both.

 

[hoz53]

OP calculated @4oz weight reduction. That’s a quarter pound. I don’t know how many here have hiked up and down the mountains for days but I have. A quarter pound here and a quarter pound there and pretty soon you just can’t make it up the mountain on day five. Everything is a trade off. I want a lighter rifle but want the velocity performance of a longer barrel. I flute mountain rifle barrels. Anyone who doesn’t think a quarter pound is a big deal hasn’t hunted mountains living from a backpack.

i always thought if i cant carry a rifle the weight of an M1, which GIs humped many many miles, I didnt deserve to go. these days i prob dont deserve to go.

 

[CT10ring]

Being involved in agriculture for a number of years and custom spraying, one individual could not plant a straight row if his life depended on it. Makes it tough to spray. His comment was he got more seeds in a crooked row than a straight one.
I find the concept of the two about the same.

I don't know ya. but that's the best dam observation. My father planted crops and plowed in eastern NC 1930's with a mule. I asked how he was able to keep the furrows straight. said "we drove a post at the end of the field and lined it up between the mules ears like a gunsight". he was a pretty good shot.

 

[epc308]

Nearly all of my barrels are MTU style tapered. Neither fluted nor bull. The resonating frequency must change along the entire length if the diameter does.

There was an interesting piece in Firearms News this month. I copied only a fraction of it.


View attachment 1190357



“The barrel features a heavy profile design with spiral flutes in three sections along its length. The spiral fluting both increases surface area while reducing the weight of the barrel. The spacing, thickness, and tapered height of the fluting were all optimized through testing. In addition, the fluting shaves .25 pounds off the barrel. The US Army claims the design allows firing at temperatures as high as 909.5 degrees F, provides a higher cook-off limit, prevents barrel droop, increases the barrel life, and allows an increased sustained rate of fire.

What is interesting is the US Army has been granted two patents on the design. They have received a 15-year design patent and a 20-year utility patent. The US Army states they believe the design may be useful on other weapon systems and is willing to license the design to commercial industry. Brian Metzger, a senior technology manager at TechLink, is facilitating licensing discussions for companies interested in producing the barrel. “The design patent reinforces the utility patent, makes it a complete package for a licensee,” Metzger stated on July 8th, 2020.”

That's certainly a different take on fluting than what you see on the rack at Cabela's.
If the image is even close to true form, it's tough to imagine that style only reduces the weight by
1/4 lb.

 

[CT10ring]

Some day I’m going to get one of those “skip fluted” barrels. They just look cool!

I've come to the conclusion fluted vs non- don't make a dam bit of difference. cool look, tho. YHM 5.56 NATO. so sexy. shoots well, no kiddin. cause skip fluted

 

[CT10ring]

Nearly all of my barrels are MTU style tapered. Neither fluted nor bull. The resonating frequency must change along the entire length if the diameter does.

There was an interesting piece in Firearms News this month. I copied only a fraction of it.


View attachment 1190357



“The barrel features a heavy profile design with spiral flutes in three sections along its length. The spiral fluting both increases surface area while reducing the weight of the barrel. The spacing, thickness, and tapered height of the fluting were all optimized through testing. In addition, the fluting shaves .25 pounds off the barrel. The US Army claims the design allows firing at temperatures as high as 909.5 degrees F, provides a higher cook-off limit, prevents barrel droop, increases the barrel life, and allows an increased sustained rate of fire.

What is interesting is the US Army has been granted two patents on the design. They have received a 15-year design patent and a 20-year utility patent. The US Army states they believe the design may be useful on other weapon systems and is willing to license the design to commercial industry. Brian Metzger, a senior technology manager at TechLink, is facilitating licensing discussions for companies interested in producing the barrel. “The design patent reinforces the utility patent, makes it a complete package for a licensee,” Metzger stated on July 8th, 2020.”

MTU great contour, agreed. have a few. patent - surprising... on a bbl contour? live & learn.

 

[Alex Wheeler]

This is the lightest rifle I have built. 4lb 14oz. no flutes. And a couple groups that it's owner shot at 1000 yards off a bipod. I prefer to just order the contour that meets the weight requirement. An interesting side note, this one is set up with .300" firing pin fall. So much for lock time.

 

[Richard Coody]

here is my understanding

Barrel's of the same weight fluted are stiffer
Barrel's of the same diameter non-fluted are stiffer

If you take your exampled of a tapered barrel and cut steel out to make the flutes you lose rigidity. However
If you took a straight tapered barrel and and removed steel to match the weight of your profile barrel
fluted barrel greatly improve the stiffness.

I think fluting has merits for all the reasons previously posted BUT cost is a real consideration.

Here is a discussion on here a couple years back.
http://forum.accurateshooter.com/threads/fluting-barrels.3967683/page-2

Cheers
Trevor

Barrel before fluting was stiffer