RE: 180 gr or 200 gr for 300 Win Mag
I like Stubblejumper's reasoning on this. I've shot elk with both the 180gr and the 200gr Nosler partition in a .300 Wby Mag. They all died in their tracks.
If you think you need more, step up to a .338 Win Mag or .375 H&H.
Good Dogwork and Good Hunting