I started my 12 yo son at the range with 50gr of Triple 7, then worked up in 10gr increments-- 250gr FTX bullets. He was comfortable with 80gr at the range, and I loaded 100gr for elk season. The adrenaline knocks off a ton of perceived recoil, so he wouldn't even feel the difference at that...
I have this same rifle with a brake. It shoots 1/2 moa out to 300 yd... maybe further but my range only goes to 300. With a lightweight Swaro Z5, this is an excellent mountain gun. It's a really shame they stopped making these. GLWS!