That is great.
Congrats to you and your son on a job well done!!

Something you might want to consider is making a m/l specially for your kid. Most m/l are very much barrel heavy and to long for kids to handle well.

I bought a used T/C Black Diamond and cut/recrowned the barrel and cut the stock to fit him. Then I put several ounces of lead in the stock. Balances really nice in the wrist.

When loaded with 75 grains of 777 and a 250 grain Hornady XTP, it is a sure fire deer gitter. Shoots very well out to 100 yards. Since I don't let either of my boys, 8 and 10 this year, shoot further than that, the gun is ideal. In the past three years they have taken 3 deer and one coyote with it.

They also have a 20 gauge with a rifled, ported barrel. My youngest likes it while my oldest likes the Black Diamond. Actually, the m/l kicks much less than the 20 gauge. But now, they can hunt during regular gun season and m/l season.
Good luck
Hank