Re: New weapons are fun!
You need to figure out what you want to do with the rifle first, then go from there. Being in Colorado and wanting to use it to hunt big game, you're looking at a AR-10 or similar .308 platform. Keep in mind everything gets more expensive with this system, especially ammo, but they're worth it if long range performance on larger game is what you're looking for.
5.56 is great for varmit hunting, even at long range, and is much more cost effective. Being on a budget and in school, I would advise staying away from any of the other calibers unless you're reloading yourself as the cost considerably greater for ammunition.
Whatever AR you end up getting, focus on a getting or upgrading to a quality trigger and free floated barrel and it will be a shooter. Everything else can be baseline stock to keep the cost down, but don't go cheap on those.
Also, keep in mind the basis of Sniper's Hide is precision shooting. You'll get some info here and there on getting weapons for doing mag dumps for fun, but not really. Putting 200 rounds downrange in a single outing is a huge range session for most precision shooters, and a typical outing is <50 rounds just to build more data. We mostly fire one shot at a time, giving full and complete concentration to that shot to put it EXACTLY where we want it.