Just read the following little bit about it.


http://precisionrifleblog.com/2014/11/18/rifle-barrels-what-the-pros-use/
"But an article written by Tom Beckstrand in the 2013 edition of SNIPER magazine summarizes some tests that Accuracy International performed to determine whether fluting a barrel affected accuracy. Here is an excerpt from that article:"

One design change that resulted from AI’s exhaustive accuracy testing and development of the PSR [Precision Sniper Rifle] is the removal of flutes from the barrels. Engineers at AI decided to isolate the barrel flutes to see what impact they had on accuracy. The engineers attached a laser to the rifle’s receiver, another to the barrel, and a third to the scope. All three dots were zeroed at the same point, then they started shooting the rifle. They discovered that, no matter which fluted barrel they used, the dots would diverge as the barrel heated. The dots from the devices mounted to the scope and the receiver would stay in place, but the barrel’s device would manifest a point-of-impact (POI) shift. The POI shift from the warming barrel greatly diminished when they used barrels without flutes.

Engineers determined that the flutes never heated evenly, causing the POI shift. I hope the results of this test gain wide circulation through the sniper and long-range shooting communities to help eliminate some of the ignorance that surrounds the perceived advantages of barrel flutes. Flutes are great for shaving weight, but this is the first test I’ve heard that provided empirical data detailing what happens when the barrel is fluted. This should be the death of the “they cool a barrel faster, so they’re more accurate” argument, listed among flutes’ virtues. Our goal is and should always be to mitigate the effects of heat; fluting exacerbates it.

I was always under the assumption that Flutes were good but didn't realize that it could cause the exact opposite of what you wanted.

But that would change other things, would it not?  Namely stiffness.  Don't the fluted and unfluted barrels of the same diameter have identical (or nearly so) stiffness characteristics?  You can match barrel weight, or barrel stiffness.  I would think the stiffness would be more critical for this test than weight.

Unless you mean they should have done the test with barrels of the same weight, in addition to, barrels of the same stiffness.

Okay.  That makes sense.  I was under the impression that for sniper rifles, weight is not a primary concern.  A concern, yes.  But not primary.  Accuracy and repeatability are paramount.

A quarter to a half pound is a big enough deal for people who are hunting while backpacking or going after mountain goats. I never do either of those things, but I do like to carry a rifle while hiking so less weight is nice.

But, none of those situations is likely to require a significant volume of fire either, so as long as the barrel will put a cold bore shot in the same place each time it's good enough. How it warps as it heats up is not a concern, so a very lightweight contour is probably fine.

Obviously in competition nobody is going to care much about carrying a few extra ounces from their trunk to the firing line, unless there are specific rules regarding weight.


So where would fluting be an advantage? What situation requires someone to carry a rifle a lot and requires them to do a lot of shooting with it in a short period of time? I don't know the answer. 

So where would fluting be an advantage? What situation requires someone to carry a rifle a lot and requires them to do a lot of shooting with it in a short period of time? I don't know the answer. 

Well, duh!  Where the cool factor is required!  Cause fluted is cool.  And spiral fluted is radically cool!   

Humor aside, in theory, I think the fluting is intended to give lighter weight compared to a non-fluted barrel of the same diameter, while at the same time keeping the barrel stiffer than a similar weight pencil barrel.  In theory.  This article seems to show that the flutings do not help accuracy as the barrel heats up.

Fluting would probably work as the theory if the flutes were held to very tight dimensional tolerances in terms of depth, width, length and orientation around the barrel.  And then stress relieved, maybe cryogenically.  But it would be a lot of work for questionable returns.

I don't question the reliability of the conclusion in the report.  I would, however, like to see the full written test protocol and the data.

If it is uneven heat dissipation due to fluting that causes the shift in POI, how many rounds were fired and over what period of time before the POI shift begins?  That would be really important to me, especially in a hunting rifle that needs to be stiff but light and will probably only be fired one time on the day of the shoot.  I would think the same thing would apply in a sniper rifle.   If it takes many rounds in rapid succession to produce the result, and the rifle is not to be shot but once or very slow rate of fire, the weight savings may be more important than protecting against a POI shift that will never happen in actual use.

It's in the data.

First off I don't care what I read so much as what I see when I shoot. I shoot a lot, it's my job. Every one of my rifles is fluted. 260, 7WSM,338LM and 308 are current loads I'm shooting a lot of. Chanlynn does make sure blank is fluted before rifled. Every one of them shoots awesome from 1st round to getting it to dam hot with a long string. 338LM is sub .5 MOA with the other three at .25 MOA hot or cold.
I think the best thing is weight savings. Makes rifle feel lighter where it counts when shooting in practical field conditions, out front. This lets you have a fatter profile which is sometimes needed for an adequate shoulder(for proper suppressor or brake mounting) while not having to carry the added weight.

But what the hell do I know

Welcome Ray.  Just noticed the link at the bottom of your post.  I'm expecting a Thunderbeast to come out of NFA jail in the next 4-6 weeks.

I don't shoot nearly as much you but whenever someone else more knowledgeable that I speaks, I listen, and the consider the facts.  At this point in time, I don't think I shoot enough to notice a difference.  And I don't think I have the skill to have repeatable shots, yet.  With that said, all of my rifles are fluted, except the AR.