Just to update everyone. The load I settled for my son is a reduced recoil load,published by Barnes, with a 120g Barnes 120g TTSX bullet and IMR 4895. This is a sweet shooting low recoil round that I am using in my gun as well.
Now we are getting somewhere! I got a 300BO AAC upper and suppressor is on order - collapsible stock is great for that age - the 7 yr old granddaughter really needs this!!!!Advanced Armament HandI Rifle 300 Blackout, $219
Protect his ears, put a suppressor on it.
http://grabagun.com/advanced-armament-corp-h-r-handi-rfl-300blk-16-threade.html