To flute or not to flute

[Bart B]

Kreiger Barrels' web site has some good info on fluting.

Button rifled barrels finished and ready for use typically get larger bore and groove diameters after fluting. Hammer forged ones are just the opposite. Cut rifled barrels ready for use typically change internal diameters the least.

If you must have a fluted barrel, have the barrel maker flute it before rifling it, then rifle and lap the bore to make it uniform in diameters.

Fluted barrels are no more accurate than solid ones. It dosen't matter how stiff the barrel is. If it did, then those long, skinny Palma barrels would not shoot just as accurate as shorter, thick ones do in long range benchrest. It only matters that they whip the same for each shot. Besides, rifle barrels whip at only around 100 cycles per second, usually less. High power bullets are long gone before the barrel goes through one whip cycle. If you think they whip at frequencies 25 or more time greater (a very popular belief in the shooting sports), you need to get in touch with a mechanical vibration engineer you can trust to give you the straight scoop.

Fluting a finished rifle barrel makes it less rigid; you've removed some of the metal that made it as stiff as it was in the beginning.

 

[Mikecr]

It dosen't matter how stiff the barrel is. If it did, then those long, skinny Palma barrels would not shoot just as accurate as shorter, thick ones do in long range benchrest

That's some pretty weak reasoning there..
For one, long range benchrest has yet to consistently break 1/2moa due to many things beyond guns used. So yeah, a good & qualified shooter can use just about any ole thing(like a 30-06) in LR BR, and then discount all other efforts.
But I suspect this is very much a reason why LR BR is not advancing really(beyond components)..

Second, it is completely known that stiffer barrels offer better potential for precision shooting. With this, IBS point blank BR shooting has settled to ~22" straight taper barrels, over lighter contour or longer barrels. They didn't go there to make weight, or to raise muzzle pressures to the point of locking themselves into flat base bullet requirements. They went there for the stiffest barrels within rule that are easier to tune and hold tune.

Now Point blank BR shooters don't go fluted as they change barrels frequently, most of which are button rifled(like Shilens), and they already hit their limit taper. If it weren't for that limit, they could go fluted bull with a bit more length, same weight, same stiffness, same tuning quality, and lower muzzle pressures for cleaner release.

These are things LR shooters should consider beyond generalizations of higher drooping barrels being good enough in certain formats of competition.
Don't focus on what they're doing, but why they're doing it, and what they might do otherwise.
What you might do otherwise.

 

[CBS]

here are a couple of ideas that may or may not be true:

quote: "Fluting a finished rifle barrel makes it less rigid; you've removed some of the metal that made it as stiff as it was in the beginning. "

that may be true. but structurally you could make a case for fluting actually increasing rigidity. (i better qualify this idea by saying that i am not an engineer and this is a point of supposition only)

if you take a piece of paper and roll it up and apply presure across the formed tube the amount of pressure that it would take to disrupt the structural integrity of the "tube" would be less in comparison to taking a piece of paper and folding it back and forth into a "fan" and then applying pressure across the fan.

this shape O has less structural integrity than this shape /\/\/\/\/\ (i understand that fluting is not a V shape it's typically more of a U or LI shape.)

this is a very elementary comparison and is comparing very unlike materials but it kinda makes sense. anyone have the equipment and a couple of identical blanks they'd like to test my idea on?

this post should not be confused with other internet FACTS. i am not stating this as fact merely pointing out that there MAY be something to the structure providing rigidity.

also, if you compare 2 barrels: 1 fluted, one non-fluted of the same "weight" the fluted may be stronger due to the diameter being larger than the non because fluting a barrel reduces the weight so you would have to use a fluted barrel of a larger diameter to equal the weight of a non-fluted barrel. so.....you may get a stronger barrel for the amount of weight but maybe not a stronger barrel of the same diameter unless point #1 above proves true.

also, if you buy a gun for $100 and sell it to your buddy for $200. then buy it back from your buddy for $300 and sell it to your other buddy for $400 how much money did you make?

 

[Bart B]

That's some pretty weak reasoning there..For one, long range benchrest has yet to consistently break 1/2moa due to many things beyond guns used.

Actually, it's very strong. The accuracy limit of long range benchrest rifles and Palma rifles are still at best, all shots inside about 7 inches at 1000 yards when test fired the same way in excellent conditions. Sure, records are the smallest groups, but all the others are much larger.

Second, it is completely known that stiffer barrels offer better potential for precision shooting.

If it was, then Palma rifles would not shoot as accurate as long range benchrest rigs. Everyone in the long range shooting sports doesn't know/belive that, so it's not "completely" known.

They (short range benchresters) went there for the stiffest barrels within rule that are easier to tune and hold tune.

All barrels hold their "tune" regarding stiffness for all shots fired. The only way they'll change is to remove or add metal to them.

You might take a look at:

Varmint Al's Fluted Barrel Stiffness Analysis

Lots of interesting stuff on fluting. Especially the conclusions at the end.

 

[Bart B]

quote: "Fluting a finished rifle barrel makes it less rigid; you've removed some of the metal that made it as stiff as it was in the beginning. "

that may be true. but structurally you could make a case for fluting actually increasing rigidity. (i better qualify this idea by saying that i am not an engineer and this is a point of supposition only)

No mechanical engineer nor anyone else will prove me wrong.

Check out the info at:

http://www.snipercountry.com/articles/realbenefitsbarrelfluting.asp

 

[Mikecr]

Bart, I realize LR guns will shoot 1/2moa or better under perfect conditions, and that many really shoot a lot better still. But LR competition guns are no where near the most accurate of guns. Not even close.
A typical 30br or 6PPC, rest fired, could better Palma groups by 4 fold at 300yds.
Now, has someone proven that longer barrels are better for accuracy?
No, they haven't. They have done well to prove the opposite..
And LR guns don't arrive with longer barrels, bigger cartridges, that don't shoot as well, out of choice. There is no choice, they must hold the capacity, and be long enough for the bullets needed to shoot further than 300yds. So the question here is whether they could benefit from a planned fluting. Well, in competitive format and ruling, fluting may not be a choice either. But all this is departing from design factors, to format factors.

So as far as competition there may not be any question ,or basis of it, one way or another.
IMO, it's a bad standard of measure -for equipment design.

 

[Bart B]

A typical 30br or 6PPC, rest fired, could better Palma groups by 4 fold at 300yds.

Folks testing good medium and long range rifles from proper rests shoot under an inch at 300. That's what the benchresters get shooting mostly in the twos (under 1 inch) at 300 yards. To better them 4 fold, they would have to routinely shoot under 1/4th inch at 300 yards.

But I well know it's nye impossible for most folks to believe that anything other than a 22 or 24 caliber benchrest rifle fired in free recoil can be equalled by any other rifle. Truth is, it happens.

 

[Mikecr]

Both a typical 30br, or a 6PPC can be relied on to cut ragged holes at 300yds. They do it like it's automatic. A typical LR gun(that is competitive at distance) only provides wallet groups like this at 300yds.
Hell every gun in my safe will consistently hit a 1"bull at 300. But there is no way I could take on a co-worker's 30br at that range. He would slaughter me so obviously..

Long range equipment is a mix of compromises, that leaves much of the distant results to the skill of the shooter. They release vastly more energy, into tighter twists, causing way more gun and barrel movements, and 2-3times the muzzle pressures. This is not tolerated for the sake of accuracy in itself, but only to be 'competitive' at distance.

So I assign LR shooting credit more to the skill of shooters, rather than standards of equipment.

 

[Boss Hoss]

Was not going to post on this but ok----first accuracy wise stay off of Snipers Hide. In every egg shoot I have participated in have beat those camo wearing dudes with (black, sniper, counter sniper etc.) rifles like red headed step children LOL! Now to stay on point my smith flutes all of my tubes and they win for me. He even flutes his own and has set world records with them and shot himself into the BR HOF and almost has enough points for a couple of the NRA classifications as well. POINT here is if the Smith knows what he or she is doing then it works like a Rolex watch if not then you have a tomato stake period end of story.

The problem is that most Smiths do not know how to process them and what barrels should or should not be fluted in the first place. For example, to flute a factory barrel may work and it may not because there is only so much that folks like Big Green can do to a blank and sell the rifle for what they do. When you remove steel and if there is stress then you have a problem as well as you change the harmonics so pay your money and take your chances. My tubes are single point cut to start with but that does not mean that other types that have been properly stress relieved cannot be fluted. Lot more to this but this is the short of it.

Flame Suit On!!

 

[Boss Hoss]

Depends on your wallet. They look cool, they help drop some weight, cool faster. That's really about it. I've had lots of fluted barrels and they all seem to shoot pretty good to amazing. Just my expierence

This guy knows a little about this subject LOL!!! He is being modest.

 

[Bart B]

Was not going to post on this but ok----first accuracy wise stay off of Snipers Hide. In every egg shoot I have participated in have beat those camo wearing dudes with (black, sniper, counter sniper etc.) rifles like red headed step children LOL!_ _ _ _ _ _ _ _ _

Flame Suit On!!

I couldn't agree more; stay off Snipers Hide for accuracy stuff. The article on fluting has nothing to do with accuracy, but some folks may not be able to make that distinction. It has to do with simple, grade school physics and the structural properties of metals. Same stuff that folks designing I beams and other things intended to maintain rigidity for whatever purpose they're made for. The laws of physics, moments of inertia and modulus of elasticity have been around longer than rifled barrels.

Sorry, Boss, if you couldn't make that distinction. I've never said fluted barrels could not shoot accurately. My point is, one does not have to flute barrels for best accuracy. Too many people have shot too good winning and setting records with plain barrels. So button up the rear flap on your flame suit you forgot to close venting your dislike of Snipers Hide so someone won't burn your back side.

 

[Boss Hoss]

HAHA---Flame suit is secure. I sent Speedy this thread and I wish I had the email response on this computer-----will post it on Monday. I think Varmit Al has some good points in his article posted above.