If this is his first hunting rifle, and you aren't planning to hunt anything bigger than "little deer", get the .243. It's the lightest recoiling of the three by a healthy margin making it much easier and more fun to shoot, and the deer aren't going to know the difference. As for the guy who said .308 ammo is easier to find and cheaper, I'd like to know where you shop. Every place I've ever been that sells ammo stocks .243's. And, I've never seen hunting rounds for .308 that were cheaper than comparable rounds for the .243. The only ammo I've seen that is cheaper for .308 is the military surplus stuff, and you can't hunt with that...