The 243 is a dual purpose caliber
The 243 is wonderful it can be a Praire dog rifle or a fine Deer rifle. The thing that must be changed is the bullet weight and construction. You are looking for a light highly explosive bullet for varmits. A light bullet going at a high speed drops less over a given distance so the hold is easier on the small Animals. When hunting Deer you are looking for a bullet that stays together and will penetrate into the boiler room for a clean kill every time.
All the ammo companies make both types of ammo for the 243, the Deer loads start at 95grains unless they are special non lead core bullets. I am sure someone on the Forum owns one (huntingman) and can offer better first hand performance on this cartridge.