I have a Ruger Ranch Rifle (7.62X39mm) with a Leupold 2-7X Scope. I can reload but will use Hornady ammo for Whitetails in Central Texas.
Regarding the best ammo, Google & Youtube is your friend. There are lots of solid reviews with excellent ammo including Hornady and ammo using Barnes TSX bullets. Out to 200-300 yard or your ability, it will do fine.