RE: .308 ammo
.308 ammo? I agree with the suggestion on Federal Premium ammo. That's all I use with my Savage .308 bolt action. Everything from the cheap target rounds (American Eagle) to the best Nosler Ballistic Tip rounds.
You just have to see what flavor of .308 ammo your Ruger Frontier will like. Federal, Winchester, Remington, Hornady, etc...