You can shoot in the heat. Just pay attention to the barrel. Grab it sometimes and if it is hot, it will let you know. I also shoot numerous rifles during the summer giving the others time to rest and cool down. I know one person that takes a cooler full of ice (and beverages) and towels. After he shoots he wraps that barrel in an ice cold towel to help cool it faster. He claims it does work. I've never done that extreme, but I will set them in the shade.

This is not such a severe problem when shooting roundball, although even they get effected. But sabots definitely show signs of barrel heating. Just make sure that before hunting season, you check the rifle and it might need a little adjustment. These guys as usual are right on the money with their advice.