Does fluting affect barrel accuracy?

[Mikecr]

For me
Button rifled= don't flute,

You must mean contouring, rather than fluting.
I would not allow anyone but the barrelmaker to contour his barrel(if button) -prior to lapping.
Fluting? I don't know that this would be a problem no matter when it's done.
Maybe if someone went crazy with it..

 

[winmag]

Hart Barrels are button rifled, & Hart offers Fluting them in a number if different patterns.
You wouldn't think a barrel manufacturer would offer this service if they thought it "hurt the accuracy" of thier barrels. Haven't hered too many negatives about them.
Usually folks mention Kreiger, Hart, & Lilja, as being in like company at the top of the pile. Many others are highly recomended too like Brux, Schillen, etc. Not all manufacturers offer fluting, but many of the top end manufacturers do. I doubt they would if it screwed up accuracy.
My 26" Hart is fluted. When Ted ("shortgrass") finishes my build ill letcha know how it shoots. I've got a hunch its gonna be fine.

 

[rscott5028]

Hart Barrels are button rifled, & Hart offers Fluting them in a number if different patterns.
You wouldn't think a barrel manufacturer would offer this service if they thought it "hurt the accuracy" of thier barrels. Haven't hered too many negatives about them.
Usually folks mention Kreiger, Hart, & Lilja, as being in like company at the top of the pile. Many others are highly recomended too like Brux, Schillen, etc. Not all manufacturers offer fluting, but many of the top end manufacturers do. I doubt they would if it screwed up accuracy.
My 26" Hart is fluted. When Ted ("shortgrass") finishes my build ill letcha know how it shoots. I've got a hunch its gonna be fine.

Congrats winmag. I bet it's a hummer too.

They do caution about contouring and fluting after it leaves their shop...
Hart Rifle Barrels

Like I said earlier... if you let the manufacturer handle it, they'll honor their warranty. Otherwise you may be alright, but you may run into finger pointing.

-- richard

 

[Joe King]

Personlly I would think that if you want a fluted barrel then get it from a top manf. They will take the necessary steps to insure that the barrel is stress relieved, but to have a barrel fluted after you recieve it is pretty much like shooting yourself in the foot.

As for stiffness, depends on how you look at it. for a given contour less material = decreased stiffness, given weight (equal length) = larger dia = stiffer

Cooling most manufactures don't feel that the added surface area is great enough to significantly aid in cooling, and less mass = heats up easier, Also a darker surface has been found to aid in cooling better than added surface area, but then again dark object s tend to absorb heat from outside sources more efficiently than lighter (more reflective surfaces, 6th grade science anyone).

BUT fluting sure does look cool
in the end though just like everything else it's just a trade off. To flute or not to flute? whats important to you? either way a good manf is most important.

 

[rscott5028]

for clarity...

I never said a 3rd party can't do a good fluting job.

But if you later have concerns about the quality/accuracy of the barrel, don't be too surprised if the barrel maker questions the fluting.

So, another approach might be to shoot first and then ask your chosen fluting smith if he'll stand behind his work and replace the barrel if the accuracy falls off.

I mention this because some after market guys have more fluting options than the barrel makers. And, some barrel makers are very conservative about the number, depth, styles that they'll do.

-- richard

 

[Greyfox]

Not too sure about all the theory but my fluted 6.5x284 Cooper and my buddy's Hart barreled 300 Weatherby will hold .5 MOA or better out to 1000 yards. I believe both are button rifled.

 

[calinb]

It is like the lottery.

It can and does occasionally effect accuracy.

It's mostly about dynamics and harmonics. Yes--they are the lottery!

 

[Bart B]

Several barrel makers I've asked about fluting all gave the same answers.

Fluting a finished barrel:

* if a button rifled one, it'll probably end up with larger bore and groove diameters under the flutes.

* hammer forged ones will probably end up with smaller bore and groove diameters under the flutes.

* those cut rifled ones typically change bore and groove diameters the least.

The all said any rifling method can be great in a fluted barrel, but only if the barrel's fluted before the gun drilled blank is reamed, rifled and lapped to tolerances.

All three also said there's no accuracy difference between fluted or solid ones with equal quality bore and groove dimensions; each one whips and vibrates at its own resonant frequency for each shot fired regardless of the cartridge or load used.

 

[Mikecr]

I agree Bart, lapping should be done following anything affecting a bore. But typical fluting is not re-contouring.
I think you'd have to go pretty crazy with fluting to actually have any affect on a barrel's performance potential. This, given that barrels to be fluted should be larger in contour.

 

[BountyHunter]

Several barrel makers I've asked about fluting all gave the same answers.

Fluting a finished barrel:

* if a button rifled one, it'll probably end up with larger bore and groove diameters under the flutes.

* hammer forged ones will probably end up with smaller bore and groove diameters under the flutes.

* those cut rifled ones typically change bore and groove diameters the least.

The all said any rifling method can be great in a fluted barrel, but only if the barrel's fluted before the gun drilled blank is reamed, rifled and lapped to tolerances.

All three also said there's no accuracy difference between fluted or solid ones with equal quality bore and groove dimensions; each one whips and vibrates at its own resonant frequency for each shot fired regardless of the cartridge or load used.

As Bart pointed out, the issue in reality is not fluting.

IT IS WHEN IT IS DONE AND TYPE RIFLING!

Button rifled barrels MUST be fluted before lapping or they will change internal dimensions. Tim North managed to flute one his barrels for me after it was rifled and get away with minor dimension changes (directly under the flutes) that he could lap out, but it still required cuttiong one inch off the muzzle.

Cut rifled, can be fluted after rifling and lapping.

Either way it is smart if you want fluting to order it directly from the mftr fluted as all will flute first, then rifle and lap.

Tons of records are shot all the time with fluted barrels so fluting by itself has zero effect on accuracy. It lightens the weight for a certain length and gives minimal more cooling effect. Actually bead blasting the barrel has more cooling effect than fluting and cheaper.

 

[durak]

Actually bead blasting the barrel has more cooling effect than fluting and cheaper.

What the H!? Where's the "article" on that theory?

 

[Bart B]

What the H!? Where's the "article" on that theory?

'Tis not a theory; it's reality.

Some years ago an article in a rifle magazine explained it. Bead blasting creates more surface area than fluting a barrel. May not seem that way, but those micro sized mountains and valleys actually transfer more heat off the barrel than fluting does. Only 10% or so, but enough to be measured. The coarser the beads are, the more surface area will be attained.

I'm not one to worry about barrels heating up. Even shooting 1 shot every 5 seconds putting 10 rounds down range doesn't change point of impact if the barrel's made and fit correctly. They've got to be properly stress relieved and fit to receivers whose face has been squared with the barrel tenon thread axis. Folks have put 20 to 40 shots downrange about 20 seconds apart starting with a cold barrel and easily put all under 1/2 MOA at 600 to 1000 yards. Lake City Army Ammo Plant shoots a couple hundred rounds of M118 match ammo for accuracy tests fired about 20 to 30 seconds apart and good lots of ammo would shoot about 1 MOA at 600 yards; at 100 yards it would shoot about 1/3 MOA.

Factory rifles rarely, if ever, have squared up receiver faces; their barrels have one hard contact point around the barrel shoulder and when they expand from heat, stress at that point tends to make the barrel bend more in that general direction while the bullet goes through it.

The only bad thing about hot barrels is if the chambered round stays in more than 20 seconds seconds before its shot, the powder has heated up and muzzle velocity will be a bit faster and bullets will strike a bit high.

Good site on barrel fluting: The Real Benefits of Barrel Fluting

The cooling effects of bead blasting can be found in several web sites; search for "bead blasting barrel cooling" and pick one that's related to rifle barrels.

 

[durak]

'Tis not a theory; it's reality.

Some years ago an article in a rifle magazine explained it. Bead blasting creates more surface area than fluting a barrel. May not seem that way, but those micro sized mountains and valleys actually transfer more heat off the barrel than fluting does. Only 10% or so, but enough to be measured. The coarser the beads are, the more surface area will be attained.

I'm not one to worry about barrels heating up. Even shooting 1 shot every 5 seconds putting 10 rounds down range doesn't change point of impact if the barrel's made and fit correctly. They've got to be properly stress relieved and fit to receivers whose face has been squared with the barrel tenon thread axis. Folks have put 20 to 40 shots downrange about 20 seconds apart starting with a cold barrel and easily put all under 1/2 MOA at 600 to 1000 yards. Lake City Army Ammo Plant shoots a couple hundred rounds of M118 match ammo for accuracy tests fired about 20 to 30 seconds apart and good lots of ammo would shoot about 1 MOA at 600 yards; at 100 yards it would shoot about 1/3 MOA.

Factory rifles rarely, if ever, have squared up receiver faces; their barrels have one hard contact point around the barrel shoulder and when they expand from heat, stress at that point tends to make the barrel bend more in that general direction while the bullet goes through it.

The only bad thing about hot barrels is if the chambered round stays in more than 20 seconds seconds before its shot, the powder has heated up and muzzle velocity will be a bit faster and bullets will strike a bit high.

Good site on barrel fluting: The Real Benefits of Barrel Fluting

The cooling effects of bead blasting can be found in several web sites; search for "bead blasting barrel cooling" and pick one that's related to rifle barrels.

Thanks Bart B

In my short 30 years a shooting in the military, hunting, sporting and some competition and living with a brother-in-law that has probably taken close to 5000 non-contoured and contoured barrels blanks from Shilen, Kreiger, Hart, Lilja, Bartlien, Douglas, and Wilson and turned them into some of the most accurate weapons on the planet, I believe I can make a few comments here.

1st - around 80% of the guns my bro-in-law builds are fluted - he flutes everyone of them himself - except mine, I do those. I have NEVER seen one shoot bad because of the fluting - in fact, in some cases I've seen barrels shoot better after they were fluted, most likely not because of the fluting but because the barrel was re-crowned and in some cases re-headspaced and trued.

2nd - Bart B - you hit it on the head - truing an action and the bolt is the key - I've seen 416 Rigby's, 505 Gibbs, and 375 H&H's shoot sub 1/2 MOA @ 200yards with Dangerous game ammo (Barnes and Woodleigh solids) and the main reason was truing the action. Those cartridges are not "supposed" to shoot that well....

3rd - In a close second to truing the action is the process in which the barrel is threaded, chambered, headspaced, and crowned. If any of these steps are done incorrectly you'll most likely have issues.

4th - I believe that handloading is to blame for most accurracy issues, especially in a custom rifle built by a competent Gunsmith.

After saying all of that, I believe that fluting has such a minimal effect on accurracy that it's not even worth discussing over other things that can seriously effect accurracy!

I know first hand one of the reasons that Shilen is anti-fluting - Law suits - I know of a Shilen barrel that was fluted by a wanna-be-gunsmith that came apart on a customer. The wanna-be-gunsmith fluted it to close to the bore and after the second shot it came apart. We all know what happened next - law suit against the builder and Shilen. How would you respond if you were Shilen?

For what it's worth.....

 

[RTK]

For what it's worth.....

Your have stated the most needed procedures to obtain a highly accurate rifle. Put everything together true and correct.

'Tis not a theory; it's reality.


Good site on barrel fluting: The Real Benefits of Barrel Fluting

The cooling effects of bead blasting can be found in several web sites; search for "bead blasting barrel cooling" and pick one that's related to rifle barrels.

Excellent article that should clear up some of the myths.