Can't recommend a brand, and it was buying factory ammo for the 7-08 that finally gave me the nudge needed to start loading, but your going to want something in 120grn or less.
The 150's still have a thump and I didn't find any that where near accurate enough for me. Settled on a factory 140 for Deer hunting. I'm currently loading Nosler ballistic tips in 120 for target/trigger control practice and even at max you can shoot those all day.
Get the 10yr old a shoulder padded vest and teach him to hold tight to the shoulder, If the Handi your getting has a padded butt plate good, if not, cut the stock and put one on. It's way worth the cost as opposed to getting a flincher, and replacing it with another longer stock as he grows is cheap,(35-50 on the stuff for sale forum).