I second the lighter load for practice and separate for hunting. My oldest two kids both practiced with a 22 until they pulled the trigger on a 243/270 on their first deer at 8. Since then, they've both went on to practice with a 243 and 270 without issues and have killed a few deer since. My youngest now 8 is practicing with a 243 w/o issue after watching the older ones.
My 11yo son drew a muzzy elk tag in NM this year so he's going to start getting some muzzy experience. I haven't worked up any loads just yet though, but may do some lighter for practice or just let him shoot standard loads from the lead sled.
