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Does fluting affect barrel accuracy?

 
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  #22  
Old 06-23-2012, 03:39 PM
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Re: Does fluting affect barrel accuracy?

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.
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  #23  
Old 06-23-2012, 06:23 PM
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Re: Does fluting affect barrel accuracy?

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.
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  #24  
Old 06-24-2012, 01:01 PM
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Re: Does fluting affect barrel accuracy?

Quote:
Originally Posted by Bart B View Post
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.
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  #25  
Old 06-24-2012, 04:40 PM
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Re: Does fluting affect barrel accuracy?

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Originally Posted by BountyHunter View Post
Actually bead blasting the barrel has more cooling effect than fluting and cheaper.
What the H!? Where's the "article" on that theory?
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  #26  
Old 06-24-2012, 05:19 PM
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Re: Does fluting affect barrel accuracy?

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Originally Posted by durak View Post
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.
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  #27  
Old 06-24-2012, 08:33 PM
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Re: Does fluting affect barrel accuracy?

Quote:
Originally Posted by Bart B View Post
'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.....
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  #28  
Old 06-24-2012, 09:54 PM
RTK RTK is offline
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Re: Does fluting affect barrel accuracy?

Quote:
Originally Posted by durak View Post
For what it's worth.....
Your have stated the most needed procedures to obtain a highly accurate rifle. Put everything together true and correct.


Quote:
Originally Posted by Bart B View Post
'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.
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