Long Range Flat shooter??????

[Curt]

[ QUOTE ]
The most accurate barrels I know of have 4 or 5 conventional grooves.

And none of 'em are fluted. Fluting a barrel changes its bore/groove diameters; moreso at the ends of the flutes than between the ends. A fluted barrel is less stiff than one of the same diameters and countours than a solid one because metal's been removed from its outside. A fluted barrel of the same weight and basic contour of a solid one is typically less than 5% stiffer; not enough to be critical.

And fluted barrels don't cool as fast as a coarse sand blasted one. If any barrel is properly stress relieved after rifling it won't bend when it gets hot.

If one must have a fluted barrel, I think it's best to have the unrifled blank fluted before it's rifled, then cut rifle the bore, then stress relieved and lapped to uniform bore and groove diameters. Krieger and Obermeyer do this better than anyone else.

[/ QUOTE ]

That is a very interesting point of view, every barrel maker that I've researched so far says that fluting not only makes a barrel much stiffer but also makes it cool faster, I do believe that you are right as far as fluting before the blank is rifled so as not to introduce stress after the fact. The info I've gathered here so far is really great, it has influenced a couple of factors for me at least. I think I'm going to spend some more time on barrel maker research, but I'm for sure going with the 280AI. Thanks again......Anymore suggestions?

 

[nighthunter264wm]

Most people are gonna tell ya whatcha wanna hear to make a sale. Basic physics tells me that the more meat a barrel has on it, the more rigid it is. Fluting looks cool. I bought a fluted barrel for my wife, but I don't want one. If you want one for the looks, get it. If you want it for anything else, save your money....

 

[Bart B]

Bearcat, check out John Krieger's web site: www.kriegerbarrels.com Go to the link/section on fluting. Note carefully what he says.

There is a lot of words (spoken and in print) saying that fluting a barrel makes it stiffer. But that's physically impossible. Here's why.

A barrel resists bending down by the force of gravity acting on it by how much material it has to resist bending. The thicker a barrel is for a given caliber and length the less it will bend. A 30-inch long 25 caliber barrel 1 inch in diameter held horizontally at one end will bend less than one of the same length and caliber only 3/8ths inch outside diameter. The reason the thicker barrel bends less is there is more material resisting compression (bottom of the barrel) and expansion (top of the barrel) in line with the force of gravity.

Holding a yardstick horizontally at one end demonstrates the same thing. With the yardstick's width vertical it won't bend much at all; hold the yardstick's width horizontal and it bends quite a bit. Again, it depends how much material resists compression and expansion in the bending force axis which is gravity. Take this yardstick and reduce its width to half, then retest. Retest again with its width reduced to equal its thickness and note how much it bends.

Anytime material is removed from the outside of a barrel there is less material left to resist bending. That's grade school physics. Any respectable mechanical engineer knows this. It doesn't matter if material is uniformly removed (reducing the outside diameter) or in lengthwise strips (fluting); there will be less material to resist bending after it's removed.

Those claiming that fluting a barrel will make it stiffer are wrong. When someone says fluting a barrel makes it stiffer, mention that some of the barrel material that resists bending has been removed. Then ask 'em why they think it would be stiffer as there's less material to resist bending.

As John Krieger says in his web site's section on fluting, a fluted barrel of the same caliber and weight per inch as a solid one a bit smaller in diameter will be stiffer. How much stiffer depends on how deep the flutes are and the outside diameters of both barrels.

A barrel with lots of deep flutes may cool a bit faster than a plain one. Someone did some tests years ago and found out a coarse bead blasted barrel cooled faster. What the cooling rate was didn't matter much as accuracy didn't suffer at all as long as the round didn't stay in the chamber more than 10 to 15 seconds before it was fired.

 

[Bart B]

Nighthunter264wm, I agree with what you said. Marketing hype exists in the shooting sports.

Some years ago, I asked a mechanical engineer to calculate the rigidity (stiffness) of two 30 caliber 1-inch diameter barrel sections; one plain and the other with eight 3/16ths inch wide flutes. The plain one was about 5% stiffer than the fluted one. Increasing the flute depth made the barrel even less rigid. Increasing the fluted barrel's diameter to equal the plain barrel's cross sectional area so the weight per inch of both barrels was the same showed the fluted one to be a little bit stiffer. About halfway between the original fluted barrel's diameter and its increased diameter, both barrels were equal in stiffness.

Besides, what difference does it make how stiff the barrel is as long as the bullet exits the muzzle at the same point in its vertical whip caused by recoil?

 

[Jon A]

The stiffness/weight ratio does matter to a lot of people though--especially those building carry rifles. In my case, a fluted #5 Lilja weighs about the same as a non-fluted #4. The first ought to be a little stiffer and cool a little faster. Probably not a huge difference but what the heck.

Good point on when it's done in the process. I don't know exactly when, but Dan does the fluting fairly early in the process exactly for those reasons.

 

[Dan B]

I will also recommend the .280AI. Mine is built on a Rem 700 action, has a 24" barrel w/ a .750" muzzle diameter. 168gr SMK's are moving just over 2900fps w/ RL-22 and will shoot .5 MOA to 500 yards (the longest range I have access to).

Sometime I'm going to try the 162gr Hornady A-Max's...I use the A-Max's in other cals and they are an awesome bullet.

 

[Curt]

OK fellas now that I've been gleaning all this great information, I was wondering if I could ask another question. I've heard some other people on the board talk about a list of very talented gunsmiths that attend this board but I've never been able to find the list. I've looked at the list on 6mmbr but some people have said these guys are good but very expensive. So I was wondering if you guys could clue me in on some places I could get a superb job of rebarreling a pre64 win to 280AI. Thanks again for all the great info!

 

[bjlooper]

Hi
Kevin Weaver builds some of the most accurate rifles out there and he is verey reasonable several of us have been trying to get him to go up on his prices. Check him out at

http://www.weaverrifles.com/

WEAVER RIFLES
16850 SAGE CREEK ROAD
PEYTON, COLO. 80831
719-683-3024
[email protected]

 

[lerch]

Now I may be wrong here, wouldnt be the first time, but I think the premis behind a fluted barrel being stiffer is that you can get a larger diameter barrel at a lighter wieght.

If you had two barrels of the same overall diameter and one was fluted and one wasnt then I guess the non fluted would be stiffer. The great thing about fluting is that you can go with the orignal large diameter barrel, have it fluted, and then you get the benefits of the large diameter barrel at the wieght of the smaller pipe.You stated basically everything I have said in your post but you seem to be talking about mostly shallow flutes. In the Lilja barrels I have been using the flutes are very deep. I would suspect that if you had a barrel of the same length as my fluted barrel but the diameter of the bottom of the flutes,

well I have a pretty good idea which one would be stiffer. /ubbthreads/images/graemlins/grin.gif


As for the barrel cooling I have always heard that the fluted barrel cools quicker because of the increased surface area, again in a barrel that has deep flutes the surface area would be even larger.

makes sense to me

take it easy
steve

 

[Bart B]

Lerch, you've made two conflcting statements:

1. "If you had two barrels of the same overall diameter and one was fluted and one wasnt then I guess the non fluted would be stiffer."

2. "The great thing about fluting is that you can go with the orignal large diameter barrel, have it fluted, and then you get the benefits of the large diameter barrel at the wieght of the smaller pipe."

Statement 1 is very true. But statement 2 contradicts it. You can't get the benefits of a large barrel (however rigid or stiff it is) and keep them after you've fluted it. Fluting it removes metal that helps makes it rigid as you said in statement 1. So the only thing you end up with is a lighter barrel that's less stiff than it was before fluting. But you will end up with barrel that's stiffer than a solid one for the same cartridge at the same weight per inch of the same length.

This subject is sometimes hard to talk and/or write about. I may hold the record for making the most contradicting statements in one paragraph about the physics of barrel fluting.

 

[lerch]

I cant see how my statment is contradictory

I do agree with you at how confusing this conversation can be though /ubbthreads/images/graemlins/grin.gif

A fluted barrel is not as stiff as a non fluted barrel of the same diameter. A fluted barrel is stiffer than a smaller diameter barrel of the same weight. I cant see how this can be contradictory.

I agree removing material from a barrel reduces its stiffness somewhat. However if you take a .900" bbl that has HEAVY flutes in it and compare it to a non fluted barrel of the SAME WEIGHT ---which one would be stiffer???

Notice that I said the same wieght, not the diameter

Confusing crap huh???????


steve

 

[dakor]

Get a 9 twist or you will regret it later.

 

[Bart B]

The part I thought was contradictory was; "you get the benefits of the large diameter barrel at the wieght of the smaller pipe."

By "benefits" that to me means rigidity and stiffness. Fluting that large diameter barrel takes away some of those "benefits." But I now understand what you mean.

Regarding: "... .900" bbl that has HEAVY flutes in it and compare it to a non fluted barrel of the SAME WEIGHT ---which one would be stiffer???"

The fluted one. The reason is there's more metal further away from bore center in the fluted one than the smaller diameter but equal weight one. It doesn't matter if the flutes are heavy (wider or deeper??) or light (narrow or shallow); fluted barrels are stiffer than a plain one of equal weight per inch. It has to to with the equations (some go to the fourth power) used to calculate stiffnes and how far the metal is away from the center of the barrel.

 

[257speed]

Bottom line, my 28" 4lb fluted barrel would be stiffer than your 28", 4lb non-fluted barrel.