Cheapest most available ammo is and will remain, 308. It’s a better fit too if you might hunt hogs or black bear, though 6.5 could handle all. The 308 however will do it in stride, without the need for premium bullets. Personally I would feel underprepared (let’s call it) hunting elk with a 243, 6.5 or 7-08, withOUT also using the best possible premium bullet such as Nosler Partition, Accubond or similar. I would not feel that way with a box of Remington 308Win 180 grain PSPCL on an elk hunt.