Im sure you know most guns will change poi when hot some more so then others. You could check to see if the stock is free floated that may help. Still a 300wby is a pretty flat shooting round and i would try and shoot the rifle at further distances to see how bad the diffrence is at those ranges. Im guessing you plan to use it for hunting? How far do you typically harvest game? No animal will be able to tell the diffrence in 2" and most dont allow for many follow up shots.
Kill em all and let God sort em out! USAF