Re: .308 vs bears
world wide millions of bears, black ,brown and white have fallen to similarly powered cartridges to the .308Winchester and including the .308 Winchester, and the majority of those long before recent new tough projectiles/bullets,
and for "novice shooters" such as yourself, a common caliber(.308 Win) is a VERY good choice as it more than adequate for all north American Big game( maybe not best for Kodiak Bears) , CHEAP/Commonly Available Ammo and LOTS of practice and familiarity with your rifle is WAYYY more important than a BAD CASE of MAGNUM-ITIS !
sit quietly by the river,,,,,,
eventually the bodies of your enemies will come floating by,,,,