I am considereing rebarrreling an upper, and would like to go with a Hbar as the current thin barrel just gets too hot sometimes (used and abused at the plinking range on hot days!).  

I was considering getting the barrel fluted, as the increased surface area would seem to dump heat into the atmosphere quicker if I remeber my thermodynamics correctly.  Here is the question:  does anyone have any kind of actual data that shows that fluting would increase barrel cooling?  Or even better, data of barrel temp on a time scale after a mag dump or something similar, comparing light profile barrels, Hbar barrels, and fluted Hbars?  

I know, a lot to ask, but I can always hope...

Dawg

a finned aluminum heat sink is best.

RAS's help, fluting our current barrel will lighten weight but by lightening weight it might heat quicker and cool quicker, basically negating any effect, fluted HBAR's are nice, almost the weight of a standard barrel but cooling and heating like an HBAR.

When it gets hot, open the bolt and let air pass through the bore, it will cool quicker.

That's why the light barrel of the 249 SAW stays relatively cool in 200-400 rds of burst fire.  It's bolt is open whenever you stop firing and air cools the inside of the barrel quicker.