All else being equal, if you compare a fluted bull barrel to a non-fluted bull barrel, then you will notice a sizeable amount of weight reduction. The thinner the barrel contour, the less you will notice the weight savings. The deeper and wider the flutes, the greater the weight reduction.
As far as heat dissipation is concerned, I can give you some real world experience. I have a Sendero Stainless Fluted (SF) in .300 Win Mag. There was a guy at the range one day that had a Sendero, also in .300 Win Mag, but his did not have a stainless fluted barrel, instead it was just a black barrel with no flutes. Honestly, it's been so many years that I don't recall if that was a stock gun, or if he had it customized, but I do remember that it had the same HS Precision stock as mine, and it also had a 700 action (except his was also black, not stainless).
In any event, I was similarly very curious about this "heat dissipation" thing, so we both took the same amount of shots in the gun booths right next to each other. I was using Factory Ammo, and he was using his own handloaded ammo. He told me that his load were not "hotter," meaning that he did not put more, or hotter, powder into his cartridges.
So, after each shooting 5 shots during a warm Miami winter morning (around 84 degrees...and yes, during the dead of winter sometimes the temp is around the low 80s around 10am) within about the same time of each other, his barrel felt a little bit hotter to the touch than my barrel, and he came to the same conclusion. Now, was this some scientific project? No. Did we have any "heat-measuring devices?" No. All I can tell you is what I told you and, based on my own lay-person's real world experience, my fluted barrel was not as hot as his. Now, is there a difference between a stainless barrel and regular black barrel? I'm not a scientist...so I don't know.
Again, all I can do is give you these facts, and you can interpret them any way you like.
Hope this helps.
Zachary
