i say it would depend on if he has shot a gun before and if he has ever deer hunted before. personally i started out with a 20 gauge single shot when i was 8 then i progressed to a winchester 1300 pump(3' shells 00 buck). i now use every gun bow under the sun, blackpowder, shotgun, rifle, bow. i dont know where u live but if in the woods or u hunt in the woods then i say let him use a shotgun for a beginners gun to learn the basics plus to he shoots at a deer with 15 pellets rather than 1 much more chance he will hit the deer. i dont know anything more dicouraging than a youngster for the first time shooting a deer and missing. but i will say if you hunt the midwest plains of lots of open area then yeh my vote for the .308 and pratice lots before you go out hunting so he gets that first deer with it and keeps on truckn to bigger and better things.