Most of my "non-range shooting is on Prarie Dogs, and yes, we keep the ammo in a cooler until it is used...just to prevent wide swings in temperature between the temperature in the morning and what it may be after 10AM... Usually it is kept in the ranch house during the night and transferred to the vehicle when we start out..
I have a series of "neck coolers" that are soaked in water and they cool through evaporation, simply by turning them over...laying one along the barrel brings the temperature down reasonably quickly and they can be rotated in and out of the water easily...
My PD shooting bench is usually covered by a cheap beach umbrella for the same reason that I wear a long sleeved shirt when out in the plains...
