Fluted barrels look cool
Other than that they do not do much for you. As Dale pointed out they save a little weight, not much; a few ounces. I have read where people have stated that it makes the barrel "stiffer". That is hog wash. They are stiffer than a skinny barrel, but not stiffer than a full rounded barrel. You can not take material away and be stiffer, period. Then there is the cooling...more surface area. I do not think this makes much of a difference either. If the flutes are not cut correctly (that is the barrel is heated up during the machining) they can get residual stresses put in or taken out that will cause accuracy problems. You do not see serious bench rest shooters using fluted barrels. There is a reason for that. They are cool though . Did I mention they are cool?
I have a stainless steel fluted barrel on a Stevens 200 and it is great looking. I bought it on sale ($100 + barrel wrench), other wise I would not have gotten it.
