"....Okay, I'm about to buy a 300 win mag, but I want to make sure I am buying the right gun. I mainly want this gun to be used for bigger hunts in the future i.e. Moose, Elk, Black bear etc..
I already have a 30-30 for deer, and a 270 in the arsenal as well...."
God bless ya. 300WinMag is a great one. A 338WinMag or 338RUM would even be better but at least you are stepping up your level of play.
Thanks for recognizing the wisdom of upping your tools to more match your intended tasks.