You get 1 gun for hunting deer. What would be your go to rifle?

What would be your go to rifle? Taking into consideration cost and availability of ammo as well. My dad's birthday is coming up and he has never been a big hunter. All he currently has is a .223 and shotgun and he mentioned getting a deer rifle if he decides to do some deer hunting at the camp. The previous owner of the camp had 3 food plots and stands already on property. He sort of figured that since everything was already set up, might as well take a deer a yr for some meat in the freezer.

Edited by Admin: you guys need to get better at your thread titles. It isn't that hard.