The AK-47 is chambered for a 7.62mm x 54mm round which definitely falls under that category. However, the AK is an assault rifle designed for high firepower, and not the kind of accuracy seen here. This is not to say that the shhoter isn't using something like a Dragunov sniper rifle, which is chambered for the same ammunition...
the infowarrior
The 7.62x39 used in AK 47s and SKSs is right at the same cartridge as a 30x30,not high power at all.
I started my kids out at about 8 years old with SKSs because of the very light recoil.