barrel fluting

[baldie]

Real world ?

 

Never noticed any accuracy difference between the two. Real accurate barrels in my own opinion are the big heavy parallel ones. They always seem better. I believe this to be the fact they take so long to warm up.

 

My own truflite has a very small section of tail off flutes. I personally would never cylindrically flute a barrel for exactly the same reason varmint Al says.

You are introducing weaker areas into the barrel to allow it to flex in an unnatural way.

 

Dont be influenced by the timberwolf. It has a worldwide reputation......and its not a good one.

[brown dog]

looks as if vermint al is a favour of fluted barrels then

 

Hi MATT 99.9% more consistant stiffer barrel for consistancey i dont know look at darrels record what he as just broke for benchrest with a fluted barrel just a thought

 

Barry, I can't have been clear - Darrel's barrel will have been stiffer than an unfluted barrel of the same weight. There's no contradiction in that; it's all good.

 

 

This was Varmint Als conclusion in the article you linked. It's exactly the same as what I said earlier

CONCLUSION ON BARREL FLUTING....

 

When comparing two barrels of equal weight, length, and material but one is solid and other is fluted, the fluted barrel will have:

 

A larger diameter

 

Greater stiffness (depending on how the extra diameter/weight is distributed)

 

Vibrate at a higher frequency (depending on how the extra diameter/ weight is distributed)

 

Less muzzle sag (depending on how the extra diameter/ weight is distributed)

 

Fluting a solid barrel will:

 

Reduce its weight

 

Reduce its stiffness

 

Increase its natural frequency of vibration

 

Decrease its muzzle sag.

 

Reducing the weight of a barrel by fluting makes a stiffer barrel than reducing the weight by decreasing its diameter.

 

A shorter barrel of the same section, solid or fluted, will sag less and vibrate at a higher frequency.

[ds1]

Out of choice I would only consider fluting on a cut rifled barrel as the fluting is done before the rifling. AFAIK it is only possible to flute button barrels and certainly hammer forged barrels after rifling - removing metal may affect internal bore dimensions.

 

Real world - what Dave said is spot on - fat, straight tube. The most consistently accurate barrel I have had was a Border cut rifled 28" 30mm diameter straight tube. To my mind the less you #### a barrel about the better....and its also cheaper but carrying the bugger soon got old quick.

 

David.

[Lee]

A direct quote from ER Shaw's custom barrel website - http://www.ershawbarrels.com/scb-fluted-barrels.php -

 

The unique appearance of our Helical Fluting provides the discriminating shooter with a barrel that not only looks great but is up to thirty percent more rigid than a similar barrel with Straight Fluting. Helical fluting provides additional surface area for improved cooling, improved barrel harmonics, and helps to counter act rotational torque, giving the shooter greater shot consistency.

 

what a load of crap.

 

"Harmonics?," I guess they will change but how does it improve?

"counter act rotational torque, giving the shooter greater shot consistency." what a freak!

 

 

if you want to remove weight by fluting and keep it stiff you need longitudinal flutes.

 

if you want to remove weight by fluting and perhaps make it look fancy but LOSE the stiffness then have spiral flutes.

Also as david said, fluting a barrel after could caus problems, best to have it done during manufacture.

[brown dog]

 

if you want to remove weight by fluting and keep it stiff you need longitudinal flutes.

 

if you want to remove weight by fluting and perhaps make it look fancy but LOSE the stiffness then have spiral flutes.

 

 

I think this qualifies as advice 'from the horse's mouth'!

[Finman]

Rigidity differences are actually significant:

 

I forget where I got these notes from so apologies to whoever I’m failing to acknowledge!

 

Rigidity is directly proportional to Moment of Inertia.

 

Fluted (OD 0.840”) versus Plain (OD 0.840”)

• Weight: 38% less

• Rigidity (as a function of Moment of Inertia): 43% less

 

The fluted barrel is much lighter, much less rigid, but has much more surface area than a solid barrel with the same overall outside diameter.

 

Fluted (OD 0.840”) versus Light Varmint (OD 0.700”)

• Weight: Same

• Stiffness (as a function of Moment Inertia): 25% more

 

The fluted barrel is much more rigid, and has much more surface area than a solid barrel of the same weight.

 

To illustrate the point, calculations of muzzle deflection based on the moment of inertia of various barrels loaded with a 500lb weight as cantilevers were given:

 

Heavy non-fluted deflection 4.4 inches.

Heavy fluted deflection 7.5 inches

Light Varmint deflection 9.5 inches.

 

Of course… that all relates to longitudinal flutes - I can't see how the same would hold true for a spiral cut.

 

 

Well, that's what I understood as well...A fluted barrel is more rigid than a non-fluted barrel of the SAME WEIGHT. So, there is no point in saying that 'I will flute the barrel of my rifle to make it more rigid', as the weight will reduce with the removal of the material for the fluting....The mind bogles...

 

Finman

[gunnery]

thanks for all your re-plys so it is looking it is possible the barrel would not shoot the same if spirel fluted is that right Lee i gather it is better to have the futing done when ordering a new barrel

[Lee]

thanks for all your re-plys so it is looking it is possible the barrel would not shoot the same if spirel fluted is that right Lee i gather it is better to have the futing done when ordering a new barrel

 

In a way yes mate, but I wouldn't go as far as saying spiral type fluting will cause accuracy problems,normal fluting could also. it all depends on who does it, when it's done and how it's done. You could have a perfect tact driver barrel one day, have it fluted but have it rendered useless because it was mounted on a machine and the crown got damaged.

 

There is a real risk like others have said of possible dimensional changes, especially on a factory barrel. If the flutes are only shallow and the barrel is pretty thick, then it may not be an issue but it really is a better idea to have it done when getting it made, if it don't shoot then you can at least send it back and have it made again. We always flute our cut rifle barrels before reaming and cut rifling, Our button barrels have to be rifled before fluting due to the manufacturing method but they get hand lapped after the fluting which is good because we can feel if things have changed.

[gunnery]

thanks for that Lee most usefull the barrel in question is a trueflight s/steel ultra match barrel i think that is a button barrel but not sure it shoots very accurately reason for all these question and trying to be sure if it should be done or not barrel size is from action end 950 to 892 end of barrel but i take your point about how it is held and damage to crown the company who is going to do the job as said he would test fire the rifle first and them when it as been fluted and gaureente the job for accuracy if i decide to have it done.

[brown dog]

Barry,

The crown is probably the least significant of potential drawbacks as it's easily remedied.

 

The big 'risk' that's been outlined is a stress change to the internal diameter of the barrel - don't know how significant that is - big for hammer forged I would suspect

 

- but manageable for button rifled would be my guess

 

[Lee, roughly how many Archer's get binned after fluting? Hardly any I suspect or it wouldn't be commercially viable to offer it as a service even at point of manufacture.]

 

The biggy, I would say, is that in terms of rigidity, a spiral flute is just a crazy concept, you may as well just turn the whole barrel down to a smaller diameter - if you're going to do it, do longitudinal.

[Lee]

 

[Lee, roughly how many Archer's get binned after fluting? Hardly any I suspect or it wouldn't be commercially viable to offer it as a service even at point of manufacture.]

 

your correct Mat, not many get binned. we have had the odd sporter barrel/light varmint feel very odd after fluting and so it has shown things can move, we put restrictions on depths of flutes to avoid problems.

 

Barry, I mentioned the crown just as another reason why a barrel that has been fluted may suddenly not shoot. Reason is that you need to put up a centre up the muzzle/crown for support which can damage the crown so may need to be re crowned again.

[devilishdave]

to create rigidity you need to move further from the neutral axis of the item so a fluted barrel would be no more rigid than a cylinder barrel of the same diameter and bore , which is more rigid a tube with a 5mm wall that is 50mm in diameter or 100mm in diameter? BUT a fluted barrel would be lighter , which i think is the main advantage ?

 

surely MG barrels would be fluted if it materialy improved cooling? i know some were in the past but nowadays i don't think they are very much?

 

they do look cool though........

 

 

The new GPMG Barrel is fluted but that was as part of project to reduce the weight the soldiers were having to lug about. A fluted barrel has a bigger surface area so it can't fail to help reduce heat just like a radiator with fins is better at giving of heat than one without.

 

Dave

[c18rch]

Machine gun barrels are not usually fluted because of the extra cost involved and given the avaerage life of a machine gun barrel they need to be cheap as chips.

[devilishdave]

Machine gun barrels are not usually fluted because of the extra cost involved and given the avaerage life of a machine gun barrel they need to be cheap as chips.

 

 

Not up to speed on the cost of a GPMG barrel but the standard hammer foged un fluted used to be £900 12 or so years ago so not what most of us would class as cheap as chips!!

 

Dave

[gunnery]

i have been convinced to leave the barrel alone it shoots very well as it is it was all to do with bling anyway but i would sooner have accuracy over bling anyday but it would have been nice i will just have the bolt fluted and make do with that not much else i can do to the barnard 07 any way thanks all you guys for your replys it was more than usefull

[brown dog]

we have had the odd sporter barrel/light varmint feel very odd after fluting and so it has shown things can move, we put restrictions on depths of flutes to avoid problems.

 

I have to say, every fluted Archer I've shot has been crazy accurate.

[c18rch]

Not up to speed on the cost of a GPMG barrel but the standard hammer foged un fluted used to be £900 12 or so years ago so not what most of us would class as cheap as chips!!

 

Dave

 

I'm not saying they're cheap by our standards but by fluting the barrel you would be adding more processes and therefore cost which is why they aren't usually fluted.