As far as I'm concerned, I'd buy a .308, but from your choices, I'd get the .243, just because the .257's are rather difficult to find a good variety for...not to degrade the round by any means, just that ain't many guys shoot it much anymore, so while you'll always find ammo for it, you'll probably only find one maker with one bullet type at each store. The .243 would be cheaper to shoot, and give more ammo choices, let alone be a bit less of a kicker for a youngster.

How young are we talking about by the way?? Actually, never mind that, I hate reading everyone's posts reaming guys for giving young kids high powered rifles at what they consider too young, you know better than I whether the kid is ready or not, do what you will.

Screw the 10 ring, keep them in the zero!!!