Regardless of caliber please do not get him a small mountain gun or youth model. Super light weapons will kick the snot outa you even in modest calibers. My buddy has a 308 mountain gun, really lightweight. Carries real nice obviously but kicks like a mule!! I am not one that is recoil sensitive, I own and enjoy shooting a 375 RUM. But don't ever ask me to shoot that 308 ever again. BTW my vote is for 7mm 08 or 308. It has to be fun to shoot at the range or he could get a flinch and never want to shoot the rifle properly.