Does Fluting a Barrel Make It Stiffer?

Just to toss a little gasoline on the discussion (and perhaps bait unclenick into the discussion since I highly value his wisdom), I have noticed when attaching a pressure trace to my rifle's barrels the characteristics of the trace vary significantly depending on where I put the gage--it appears that all other things being equal the thicker and more consistent (meaning distance from ID to OD is uniform) the metal is, the more consistent the modulus elasticity is. The molecular quality of the steel itself probably plays a big role. But this may be just fizzics speculation (or misunderstanding) on my part.;)
 
Last edited:
I don't care either way, if I order a fluted barrel it is trying to save some weight. Like the last barrel I ordered an 18" magnum contour Savage prefit, I had it fluted to try and make an overall weight goal of the rifle. I missed it by at least a pound over my goal weight, but I needed a heavier contour barrel to have enough muzzle diameter to thread for my suppressor.



I was hoping it would come in at 2.5 lbs, not 2 lbs 15 ounces (14.9oz). Easiest way to save weight when building a rifle is barrel and stock, I missed on both accounts because I didn't want to spend the money for a carbon fiber stock or custom contoured or carbon fiber barrel. To save that pound of weight would have cost me about $62.50 an ounce.

I look at it as a learning experience, and I'll shoot it and build a true custom if it works as well as I hope. I'll try to go from an 11 pound scoped rifle down to an 8 lb scoped rifle. That would sure make it more enjoyable to carry.
 
Engineering is great.
Till the first turn. :rolleyes:

Paper & real world experience end up being very different things.
Reduced weight be darned, people keep forgetting that when it comes to metals, form has it's own structural function.
 
If your sundeck is made with 2 x 6 boards vertical set against each other, will it be stiffer if every other one is replaced with a 2 x 4?
 
Bart B. said:
If your sundeck is made with 2 x 6 boards vertical set against each other, will it be stiffer if every other one is replaced with a 2 x 4?  
Click to expand...

Doesn't matter to me, I'm too cheap to build a deck that way! ;)

It has been my experience that a fluted barrel is still more accurate than most people pulling the trigger.
 
I agree. So are standard barrels.
Click to expand...

Bart seems to have a relatively low opinion of the shooting ability of “most shooters”. I don’t blame him - unless they “do their part” of course. :D




.
 
Compare a solid round steel bar to a hollow steel tube that has the same amount of material. The cross sectional areas of the bar and the tube are the same, but the cross sectional area of the tube is distributed at a larger radius from the center line than the cross sectional area of the bar. That makes the tube stiffer than the solid bar. If you remove material from the outside diameter of both the solid bar and the hollow tube by fluting, the cross sectional areas are reduced, and the radii to the centroid of the areas are also reduced. That makes the fliuted bar and cylinder less stiff than the unfluted versions.
 
TX Nimrod said:
Bart seems to have a relatively low opinion of the shooting ability of “most shooters”. I don’t blame him - unless they “do their part” of course. :D
.
Click to expand...
What percent of shooters can sight in their very accurate rifle without artificial support? Offhand or standing without a sling and only 3 shots.

"Most people" means any amount over half tested.
 
Last edited:
If anyone is really in doubt as to reducing weight NOT being a factor on stiffness, but FORM giving more stiffness, go to your nearest overpass.

I can't remember which edition it was, but a few years ago, Racecar Engineering had an in depth article regarding a wheel hub. They removed 1.5 lbs (no small feat for a racing hub!)
but made it 30% stiffer. Same material used, the holes were radioused differently, and ribs put in by removing material.

I've said it before, i'll keep saying it.
Form is a function when it comes to metal.
It's been proven for hundreds of years now.
 
If your sundeck is made with 2 x 6 boards vertical set against each other, will it be stiffer if every other one is replaced with a 2 x 4?
Click to expand...

I like your analogy. It is similar to barrels in a couple of ways.

1. It would be less stiff with 2x4s. But the average person walking on it wouldn't notice.

2. The stiffness is dependent on who does the work. If I assemble the deck with every other board being a 2x4, it will be stiffer than if the average office manager did it. I am a professional carpenter and I understand the principal's of woodworking. Likewise, if a barrel maker has lots of testing and practice fluting barrels, they will make a stiffer barrel than a newb. But neither of them will make it as stiff as a solid barrel. And the average shooter probably won't be able to tell the difference. ;)
 
It’s been a few years :) but we actually addressed this question in a “Solids and Materials” 300- level Engineering class for bending moments.
The math wasn’t simple but the summary answer was:

For the *same weight* of the same material in a linearly fluted and non fluted barrel, the fluted barrel is stronger. (Implies the OD of the fluted barrel is larger by the amount of fluting removed)

For the same outside diameter of fluted and non fluted barrel, the non fluted barrel is stronger.

Caveats:
There are some corner cases (such as the flutes are as deep as the barrel is thick) with opposite results.
 
TXAZ is right on, I was trying to figure out simple way to put it but I guess don’t get planer.
The mind bender for a lot of guys is the barrels in question are not the same diameter when you go by weight. I don’t know why they throw this in. When you are talking different diameters it is apples and oranges.
 
I get what Bart B. is trying to teach us. Think twice before you order that fluted barrel. However, I have three button rifled fluted barrels on factory on a M70 EW, one fluted by Twisted Barrel as an after thought to save some weight, and the one by X-Caliber pictured. The two that I'm shooting right now do extremely well, the third hasn't been properly installed yet.

I also used to have a Lilja that was fluted on a 03A3 in .338-06 and I was able fo find a sub MOA load with every bullet I tried. Some were easier than others, but the results were repeatable over several groups (yes some were only 3 shot groups, but many were 5 or more). I traded it to a buddy who makes custom knives, and he's reporting the same results.
 
You must log in or register to reply here.
Back
Top