For a 6 year old: I’d buy a rifle he could

- carry A LOT with fear of marring it up
- shoot A LOT without fear of developing a flinch (recoil and report)
- reasonably accurate

For $3k …. Goodness. I’d get a Ruger American shorter barrel/Compact in 6.5 Creedmore with a threaded barrel. Beat the crap out of it with no fear. Buy a threaded suppressor to decrease recoil and report. Buy electronic headphones on top of that. I’d get a scope with high eye relief and field of view. This translates to a large ocular size (which with a 60 degree throw on the ruger American works well). All the rest devote to practice ammo.

If yon have money left over, buy a .22 for target practice