All the above calibers are fine, but to spend a day at the range shooting to me says surplus ammo. From that standpoint, .308 is very economical. Much of the military brass is also heavier and reloadable and there is a huge selection of bullets and weights available for the reloader. I've got lots of military 7.62NATO brass and it is excellent. Most of the 6mm, 6.5mm or 7mm chamberings would be fine for hunting deer, but I see more match rifles in .308Win/7.62 NATO.