My son is in the process of applying for NROTC - Marine Option. Precision rifle has been great preparation.
My son had never shot an M-16, but managed to qualify as expert at USMC boot camp despite having rifle training cut short by bad weather. He got 5 in the black at 500 meters with iron sights.
I used to take the kids shooting out in the country. Mostly .22s but I did let them shoot an AK clone (MAK-90) or my SKS often. Ammo for that was so cheap way back when.