I agree with fiveinadime, read and learn from reloading manuals. I will try to start you in the right direction.
Bullet weight has very little to do with a given bullets accuracy. However a rifles twist rate will determine what bullets it will stabilize. Therefore it makes some bullet weights inaccurate in certain rifles. The heavier a bullet is, in a given caliber, the the more twist is needed to stabilize it. The 30-06 is usually rifled to a 1/10 twist rate. That means that the bullet rotates 1 time in 10 inches as it moves down the barrel. That will stabilize most 30 cal. bullets.
Heavier bullets tend to get more penetration. Needed for hunting larger animals. A heavier bullet will hold its velocity longer than a lighter bullet, if they are the same shape and caliber.
You will learn a lot more if you search the old posts with key words. Take some of the posts with a grain of salt, not everyone on here knows as much as they think they do. The general consensus is usually correct.
You can't fix stupid....however ignorance can be cured through education!