Thread: Barrel Fluting - Best Practices?

To address the original question, you can do spiral fluting on any bridgeport mill via the X drive powering the rotation of the dividing head. Sure it's old school, but it was machining spiral pumps, cutters, etc. long before most of us were born. It's what I learned on in the 70's. I'm just not convinced that spiral fluting does anything other than look cooler compared to straight or dimpled fluting. That would take a lot of barrels and shooting to prove out one way or the other.

I believe some people like it because their taste is in their mouth. It can induce stress in your barrel. You can reduce the weight of your barrel fluting it. Most comical thing is the folks saying it makes them "stronger". Chuckle, chuckle.

Originally Posted by Butch Lambert

Most comical thing is the folks saying it makes them "stronger". Chuckle, chuckle.

I ran into that a lot when people would ask me to do it so their barrel was 'more rigid'.

It's because some advertise fluted barrels in a deceiving way, or people just misinterpret what people advertise. Yes, -ounce for ounce- a fluted barrel will be stronger than one not fluted. But if you take an existing barrel and flute it, all else isn't equal. You've removed material. A 24oz fluted barrel will be stronger than a 24oz straight barrel of the same weight... because for those conditions to be met, the fluted barrel with have a larger outside diameter. GENERALLY SPEAKING. Still more variables to it..

I often had to tell people that never, in anything I can think of, will the removal of material result in a STRONGER or STIFFER object. (obvious punchline setup is obvious)

To put it simply, fluting your barrel will not make it stiffer.

How often do barrels warp when fluted? Seems it would relieve sometmes-uneven internal stresses, maybe add some if the cutter is not very sharp.

Looks like straight flutes would raise the natural frequency of the barrel, dimples or helicals might lower it.

Other than lightening,(and coolmosity), what virtues are claimed?

Looks neat.

Fluting does accomplish a couple of things for you besides the "looks cool" factor.

Primarily, it allows you to decrease the weight of your rifle, while maintaining a stiffer barrel than what a like weighed "pencil profile" barrel would be. That also translates to being able to carry a longer barreled rifle that weighs less than it otherwise would have for hunting. Remember the goal is to carry a light rifle, but shoot a heavy one for accuracy and comfort. Fluting helps nudge you in that direction.

Secondary, it can assist with cooling the barrel if you're doing a lot of shooting. More surface area = a better radiator for helping to keep your barrel cooler than a non fluted barrel would be.

I've heard the argument that it can decrease the harmonics, but I've not seen a study that proves that.

As far as warpage goes, an uneven fluting on a non stress relived barrel can warp. Ditto an uneven fluted barrel once getting hotter from firing can cause your point of impact to drift, much like a warming rifle barrel that is making too much contact with the stock.

Originally Posted by magneticanomaly

How often do barrels warp when fluted? Seems it would relieve sometmes-uneven internal stresses, maybe add some if the cutter is not very sharp.

Looks like straight flutes would raise the natural frequency of the barrel, dimples or helicals might lower it.

Other than lightening,(and coolmosity), what virtues are claimed?

"Assist with cooling"

You removed mass so the barrel will heat up faster.

It doesn't dissipate heat faster because of increased surface area. The surface will actually heat up faster than a comparable bull barrel.

It dissipates heat faster because the fluting creates a thinner wall, allowing the heat from the bore to reach the outside faster and then radiate away. Same results, just a slight misconception that's very commonly repeated, as to why it does indeed cool a bit faster.

When you think about it, if you are shooting a lot you want more surface area since that transfers the heat to the air. If you are shooting intermittently you want more mass, since even though it will store the heat it will spread the heat around.

If you shoot a lot with too little surface area the barrel will get hotter and will stay hotter longer.

Originally Posted by dbsuthe

When you think about it, if you are shooting a lot you want more surface area since that transfers the heat to the air. If you are shooting intermittently you want more mass, since even though it will store the heat it will spread the heat around.

If you shoot a lot with too little surface area the barrel will get hotter and will stay hotter longer.

If you are shooting a lot, chances are you are putting far more heat into the barrel faster than even the surface area of the flutes coukd dissipate. I'm betting you would see negative affects from a fluted barrel getting hot before a round barrel.

I'm sticking with the main benefit of a fluted barrel is making your wallet lighter.

I make absolutely no pretense to expertise on the topic of fluting/heating/cooling/harmonics etc. Clearly one gets the benefits of a lighter rifle. But, beyond that...? Seems like it might be reasonable to say the net effect of fluting --good or bad-- is not really that great. Am I wrong?

Squire

Sent Using Tapatalk - Cherokee Nation of Oklahoma, Tahlequah OK

Originally Posted by 300sniper

If you are shooting a lot, chances are you are putting far more heat into the barrel faster than even the surface area of the flutes coukd dissipate. I'm betting you would see negative affects from a fluted barrel getting hot before a round barrel.

I'm sticking with the main benefit of a fluted barrel is making your wallet lighter.

And if one doesn't know for sure what the conclusion is, a real good indicator is to just show up to a decent long range match... sometimes "tradition" trumps fact in the gun world, but when it comes to the barrels of the long range 'accuracy assholes' (I say that endearingly) I'm confident that if everyone has features of a barrel pretty consistent... that's what a detective would call "a clue"

Originally Posted by OldSquier

I make absolutely no pretense to expertise on the topic of fluting/heating/cooling/harmonics etc. Clearly one gets the benefits of a lighter rifle. But, beyond that...? Seems like it might be reasonable to say the net effect of fluting --good or bad-- is not really that great. Am I wrong?

Squire

Sent Using Tapatalk - Cherokee Nation of Oklahoma, Tahlequah OK

See post #26 for my summary, lol.

Originally Posted by JNieman

See post #26 for my summary, lol.

LOL! That's the conclusion I was coming to!

Squire

Sent Using Tapatalk - Cherokee Nation of Oklahoma, Tahlequah OK

A fluted barrel is lighter barrel with the same stiffness: One would have to prove to me that a CBS is more likely with a fluted M40 contour than it is with a medium palma.

A fluted barrel cools faster than a non fluted. First, you'd have to explain to me what type of shooting you are doing where heat is causing issues. Next, you'd have to explain to me how a barrel that heats up faster but cools faster once you are done shooting is a benefit.

A fluted barrel looks cool, AKA, chicks dig it: OK, if that's your thing, and you are willing to admit it (and pay for it), I'm cool with that.

In my opinion, there are two honest reasons for a fluted barrel: you already have a finished rifle in possession and it is too heavy but are willing to pay for it (and potentially sacrifice accuracy), or you simply like the look. Any other reasons, you're kidding yourself.

And don't get me started on a fluted bolt body on a two lug action...

Originally Posted by 300sniper

And don't get me started on a fluted bolt body on a two lug action...

How else are you gonna get it to hang up on the feed lips when you're resting the rifle on the magazine?

An old thread to be sure, But....

I'm figur'n to 6 flute a .308 H-Bar
.25 radius, .065 and .045 deep on the two diameters.

Horizontal mill, barrel held in vee block adaptors in a Kurt vise.
Indexing will be by registration of a 5-C hex block restrained in a second vice on the mill table. The collet will "grip" a threaded muzzle cap (5/8-24) at 3/4" diameter.

Question??? I want to "blue" the fresh metal flutes to contrast the presently parkerized barrel finish. What happens when cold blue hits parkerized? A mess?

I'm not sure that I'll like the result, but it will be different. ;-) That's why they invented cerrocoat!

Originally Posted by CalG

An old thread to be sure, But....

I'm figur'n to 6 flute a .308 H-Bar
.25 radius, .065 and .045 deep on the two diameters.

Horizontal mill, barrel held in vee block adaptors in a Kurt vise.
Indexing will be by registration of a 5-C hex block restrained in a second vice on the mill table. The collet will "grip" a threaded muzzle cap (5/8-24) at 3/4" diameter.

Question??? I want to "blue" the fresh metal flutes to contrast the presently parkerized barrel finish. What happens when cold blue hits parkerized? A mess?

I'm not sure that I'll like the result, but it will be different. ;-) That's why they invented cerrocoat!

Parkerized? Is this a factory hammer forged barrel? If so, I'd personally avoid fluting it. The bore would almost certainly move on that.