You can always get a cooler with those frozen gel packs so you don't get any moisture in the gun if your that worried. But you will get condensation in there. As for rounds cooking off, Go too the mythbusters site on youtube. They cooked loose round off at the bomb range in a fire, it takes awhile for the primer to boil in fire to cook off. Basice rule of thumb is if you can stand the heat odds are your ammo can as well, but don't quote me on that.