TWhy not let him know there's a rifle of his choice waiting if/when he wants to get serious about hunting?
Then let him get on with his life?
g
OP explained from the beginning that his son likes to hunt, but just isn't into thinking or caring a lot about what rifle he uses, other than making sure it's sighted in. Nothing wrong with that. Nothing wrong with dad getting him a new one, with which son can do with as he pleases.
Seriously, if he's bored with the one cool bolt rifle he owns, I would consider getting him an accurate semi-auto. That might light his fire in becoming more interested in rifles or not. But getting him another bolt gun that won't do anything that the one he already has will do, probably will get a yawn from him. Maybe get him some short-range compact big-bore or handgun cartridge lever action. I personally wouldn't ask him what he wants. Surprise is much of the benefit of getting a good gift.
