The biggest differences you'll see are weight. I shot an octo .25-35 barrel in IHMSA Production Class for years and hit 40x40 with it repeatedly so the accuracy was there, and recoil wasn't bad either since the small hole kept plenty of weight in the barrel. However, my .45LC octagonal is brutal in recoil with loads much above factory because the barrel weighs almost nothing. Both are with irons sights; the weight of a scope will help mitigate the recoil.
How fast a barrel heats up is due almost entirely to its mass, not shape. Two barrels with the same diameter, one with flutes the other without - the latter cools off faster, but its temperature will rise faster so it is often a wash.
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