Bull barrels are around because of HEAT SOAK. That is why we have fluting. It makes the barrel a little lighter but that is not the reason. Fluting makes for more surface area, heat can only radiate so fast from so much surface area. The only way to get rid of more is increase the surface area.
Just look at any thing that has to dump a lot of heat real fast, like radiators. They don't have all those funny little frills at the front for the looks u know.

I just had to say this about bull barrels, its far easier to hold a rifle still if its heavier at the muzzle when using a by-pod or try-pod.
I do the same thing with the bow, its easier to shoot accurately with a weight stuck out on the ends of a stick than it is stock.