Nothing wrong with a 6mm. I doubt I will ever be without a 243! That said a kid..or anybody..can burn up alot of ammo. Hard to get cheaper than a 223. And the more trigger time, the better.
Hell, i had my buddies kids maybe 13ish years old. Shooting a few rifles of mine across a canyon. I had a blast watching them learn how the drop chart, reticle and rangefinder all worked together. They shot the hell outta the 223 until they got to try my sendero 300rum in a krg chassis. Lil [bleep] burned through 50 rounds of 300 ammo pretty quick. They loved it, but I sure wouldn't wanna keep those kids stocked with that ammo
