Re: I am shooting nosler 155 match and nosler 168\'s
I think if your barrel is not free floated, it could tend to throw bullets of different weights and/or speeds any which way, depending on the actual barrel time.
A barrel which is pressure bedded at the forearm tip, and not relieved along each side of the forearm channel, will at some point in its vibration cycle be pressed against one side of the forearm channel or the other. If the bullet exits during this period of time, the muzzle would be pushed to one side, and the bullet would of course go that way.
In a free floated barrel (which, in my opinion, is the best way to obtain good shot to shot consistency) there shouldn't be more than an MOA or two at most of lateral movement, just as Bart mentions.