For starters, I will be using this rifle for hunting mainly. I plan on using a savage action. I am wanting to use either a 7mm RUM or 300 RUM. I want to use it for all big game. I was wondering what barrel length and o.d. was thinking 28-30 inches in a 1" diamiter. Also so many great barrel companies out there, what one should I choose? Also what twist rate? Thanks in advance.