I wouldn't worry so much about the kid outgrowing the rifle and needing a different one down the road. Lot's cheaper to get him something he will enjoy and which will wet his appetite for more.
Getting him a rifle that he won't enjoy shooting...and won't shoot it much...is the worst investment.
"The whole problem with the world is that fools & fanatics are always so certain of themselves, and wiser people so full of doubt" Bertrand Russell
