What does this do (advantages) over a more traditional pattern?
I'm thinking it has practical disadvantages... Removing material linearly creates bridges the length of the barrel, essentially yielding a medium contour barrel with vanes the depth and length of a heavy barrel. Dimpling reduces weight without causing weak spots. Both allow reduction in weight and increased performance over using just a lighter barrel.
Now this fluting, it would seem to me, would cause the barrel to whip more, not less, due to all the weak spots, since the second pass at fluting actually serves to cut the "bridges" formed by the first pass. And the spiral fluting, well, I'm not so sure that is the best way either because when a barrel, any barrel, whips, it looks a lot like it is whipping straight up and down. A spiral would appear to either be less effective than straight fluting, may cause inaccuracy, OR it could increase strength AND accuracy if it were engineered to the nth degree and computer models were constructed... There is possibility there, but I doubt anyone is doing that, taking it that far.
This is just from looking at it, I'm obviously not gonna run the numbers on it, I'm not that interested in it and I don't have the programs, I'd have to do it by hand. Myself, I go with deep, wide fluting on heavy barrels, or dimpling on mediums if I can.
I suppose it may look cool, but I feel just from looking at it that it isn't practical or as practical as other ways, and it also looks like more weight could be removed while retaining more strength with traditional ways too. But whatever floats your boat, eh?
Good job, and kudos to Boltfluter, the maker, he made what he was asked to make and it looks quite nice indeed. Now fluting like this, the same diamond pattern on the bolt... I can see it being very useful in some cases, particularly if you are in an area where crap gets in there and makes tight fitting bolts not want to work.
I'm guessing you fluted a finished barrel. What do you think about cutting and fluting the exterior of the bar stock first, then boring and cut rifling that afterwards so as to reduce stress? To make it more accurate?