Dude, for a first time handgunner, the 460 is probably too much to deal with. It will certainly do the job, but if you want to kill a Pa. Black bear, go with a 44 magnum and if you don't handload, then go with
Cor-Bon 320gr. bullets. Cor-Bon also makes a 305gr. 44 mag bullet that will do the job on bear.
For whitetail, anything 200gr. or better will get the job done. I handload and I've killed 'em with my "standard" whitetail load of a Hornady 200gr. XTP over 24.4gr. of Vihtavouri N-110 powder. Some guys use a 240gr. bullet for whitetail (which is fine) but I've not had one that hasn't dropped in it's tracks with the 200 grain.
Bullet placement is (like anything else) key. If you hit 'em in the arse with a bazooka, they aren't gonna die real quick. (Angle of entry too be considered!!)
Dave